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تعداد آیتم قابل مشاهده باقیمانده : 3 مورد
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Labor and delivery: Management of the normal first stage

Labor and delivery: Management of the normal first stage
Authors:
Edmund F Funai, MD
Errol R Norwitz, MD, PhD, MBA
Section Editor:
Malavika Prabhu, MD
Deputy Editor:
Vanessa A Barss, MD, FACOG
Literature review current through: Oct 2022. | This topic last updated: Sep 09, 2022.

INTRODUCTION — Labor is defined as regular and painful uterine contractions that cause progressive dilation and effacement of the cervix. The World Health Organization (WHO) defined normal birth as "spontaneous in onset, low-risk at the start of labor and remaining so throughout labor and delivery. The infant is born spontaneously in the vertex position between 37 and 42 completed weeks of pregnancy. After birth, mother and infant are in good condition" [1].

This topic will present a paradigm for intrapartum management of the first stage of labor (ie, onset to full cervical dilation) in pregnant people who are expected to have a normal singleton vaginal cephalic birth. Many of the options for caring for these patients have not been studied in high-quality clinical trials and the available data are insufficient for making strong recommendations for a specific approach. Therefore, much of our approach is based upon our clinical experience, data from observational studies, and expert opinion.

Intrapartum care of these patients in the second and third stages of labor is discussed separately:

(See "Labor and delivery: Management of the normal second stage".)

(See "Labor and delivery: Management of the normal third stage after vaginal birth".)

Detailed discussion of specific subjects related to labor and birth and intrapartum care of complicated labor and birth are also reviewed separately in individual topic reviews on each subject (eg, abnormal progression, preterm labor, cervical ripening and induction, operative vaginal delivery, cesarean birth, malpresentation, analgesia and anesthesia, support, maternal medical/obstetric disorders, episiotomy, multiple gestation, postpartum hemorrhage).

Management of labor and delivery during the coronavirus disease 2019 (COVID-19) pandemic is reviewed separately. (See "COVID-19: Intrapartum and postpartum issues", section on 'Approach to infection control during the pandemic'.)

CREATING A SATISFACTORY CHILDBIRTH EXPERIENCE — Factors that are important in determining an individual's satisfaction with their childbirth experience include [2-6]:

Their personal expectations and ability to cope

The amount of support they receive

Their involvement in decision-making (ie, personal sense of empowerment and control)

The quality of the caregiver-patient relationship (eg, mutual trust and respect, good communication, continuity of care, understanding of and sensitivity to the patient's values and sociocultural context, sense of security)

Minimal use of interventions

Studies suggest that the severity of pain is not a critical determinant of maternal satisfaction, but the individual's expectations about labor pain and their ability to make decisions about utilization of various options for pain relief are very important [7]. (See 'Pain and pain management' below.)

Many of the factors discussed above are addressed in childbirth preparation classes. These classes inform pregnant people and their partners about what to expect during labor and birth and provide a foundation for developing personal plans for their birth experience. (See "Preparation for childbirth".)

Support by a doula is also helpful. A doula provides one-on-one continuous support during the birthing process and focuses on patient factors that have been associated with a positive childbirth experience. (See "Continuous labor support by a doula".)

SITE OF LABOR AND BIRTH — Hospitals and birth centers are considered safer locations for birth than the home because of the availability of physicians, blood transfusions, antibiotics, anesthesia, and other resources for intensive/emergency maternal and newborn care, if needed [8]. (See "Birth centers".)

However, a planned home birth with a registered midwife or appropriately trained physician in a well-integrated obstetric system can be a reasonable choice for persons with a low degree of risk where the birth is anticipated to be uncomplicated and neither the birthing parent nor the neonate will require resources beyond the local capacity [9]. This is especially true for patients with at least one prior vaginal birth. Home birth is less successful for nulliparas, resulting in transfer to a birth center in at least 30 percent of attempts based on data from the Netherlands. These data are reviewed separately. (See "Planned home birth".)

WHEN SHOULD THE LOW-RISK PARTURIENT BE ADMITTED? — There is consensus that patients in active labor should be admitted. The National Partnership for Maternal Safety suggests assessing the presence of all of the following factors in making the diagnosis of active labor [10]:

Regular contractions that require the individual's focus and attention

Significant cervical effacement (≥80 percent)

Cervical dilation at least 4 to 5 cm with documented cervical change, since most patients enter the active phase of labor at 4 to 6 cm

Given that patients cannot check their cervical dilation or effacement, many will present for a labor check before cervical dilation reaches 4 cm. If maternal and fetal well-being are confirmed, these patients can either be admitted to the Labor and Delivery Unit or discharged. Both approaches are reasonable. Although patients admitted at <4 cm cervical dilation are at higher risk for iatrogenic intervention, the maternal and perinatal consequences of sending these patients home have not been studied adequately.

At least two studies have provided data on this issue:

In Washington State, the Bree Collaborative Obstetrics Care Report attempted to influence clinical practice by recommending admission for spontaneously laboring patients at term with uncomplicated pregnancies only when cervical dilation was ≥4 cm [11]. The clinician determined whether the pregnancy was low risk, performed the assessment and reassessment, and provided appropriate counseling for patients who were not admitted. Adherence to the work group's recommendation was not mandatory.

After publication of this report, a retrospective cohort study of over 11,000 singleton, term deliveries in Washington State observed a 10 to 15 percent increase in hospital admissions at cervical dilation ≥4 cm [12]. Patients admitted with cervical dilation ≥4 cm were less likely to have epidural anesthesia, oxytocin augmentation, or a cesarean birth than those admitted with cervical dilation <4 cm. The authors were unable to identify patients evaluated for labor, sent home because of cervical dilation <4 cm, and subsequently admitted; thus, the safety and efficacy of the change in clinical practice could not be evaluated.

A study from Texas including over 6000 pregnancies reported that, after evaluation, discharging patients with "false labor" at term (n = 3949) was not associated with an increase in adverse outcome [13]. Criteria for discharge were intact membranes, cervical dilation <4 cm, no cervical change or contractions at the end of two hours observation, and normal fetal heart rate (FHR) tracing. Patients were excluded from the study if they had pregnancy complications or a previous cesarean birth.

HEALTH PROFESSIONAL — Most patients with low-risk pregnancies receive intrapartum care from either a midwife or physician. Ideally, the choice is based on the patient's values and preferences.

In a 2016 meta-analysis (15 trials, over 17,000 participants [most with low-risk pregnancies]), those who had midwife‐led continuity models of care were less likely to experience intervention, more likely to be satisfied with their care, and had at least comparable adverse outcomes to patients who received other models of care (eg, obstetrician, family medicine physician) [14]. The following examples illustrate outcomes for midwife-led versus other models:

Spontaneous vaginal birth: 69 versus 66 percent (risk ratio [RR] 1.05, 95% CI 1.03-1.07)

Cesarean birth: 14.3 versus 15.5 percent (RR 0.92, 95% CI 0.84-1.00)

Forceps- or vacuum-assisted birth: 12.9 versus 14.3 percent (RR 0.90, 95% CI 0.83-0.97)

Intact perineum: 27.9 versus 26.9 percent (RR 1.04, 95% CI 0.95-1.13)

Neuraxial anesthesia: 23 versus 27 percent (RR 0.85, 95% CI 0.78-0.92)

Amniotomy: 31 versus 42 percent (RR 0.80, 95% CI 0.66-0.98)

Augmentation with oxytocin: 24 versus 29 percent (RR 0.88, 95% CI 0.78-0.99)

Perineal laceration requiring suturing: 38 versus 34 percent (RR 1.02, 95% CI 0.96-1.10)

Episiotomy: 19 versus 23 percent (RR 0.84, 95% CI 0.77-0.92)

MANAGEMENT OF THE FIRST STAGE OF LABOR

Initial examination — The goals of the initial evaluation of the parturient are to:

Review the prenatal record for known medical or obstetric conditions that need to be addressed intrapartum.

Determine whether new disorders have developed since the last prenatal visit.

Evaluate fetal status.

Confirm that the patient is in labor – This is sometimes difficult as painful uterine contractions alone are not sufficient to establish a diagnosis. Typically, the diagnosis is made in patients with uterine contractions that result in progressive cervical dilation and effacement over time; a recent history of membrane rupture or bloody show (vaginal discharge of a small amount of blood and mucus [ie, mucus plug]) supports the diagnosis. The diagnosis can also be made on initial examination in a patient who presents with contractions and advanced cervical dilation and effacement (≥6 cm).

The following assessments comprise the initial examination:

Admission vital signs include blood pressure; heart and respiratory rates; temperature; frequency, quality, and duration of uterine contractions; and fetal heart rate (FHR).

Physical examination – Digital examination is performed after placenta previa and prelabor rupture of membranes (PROM) have been excluded by history and physical, laboratory, and ultrasound examinations, as appropriate.

The purpose of the initial physical examination is to determine:

Whether fetal membranes are intact or ruptured – (See "Preterm prelabor rupture of membranes: Clinical manifestations and diagnosis" and "Prelabor rupture of membranes at term: Management".)

If the membranes have ruptured, the presence of meconium should be noted because of the possibility of meconium aspiration. (See "Meconium aspiration syndrome: Pathophysiology, clinical manifestations, and diagnosis".)

Whether uterine bleeding is present and excessive – Bleeding can be due to placenta previa, vasa previa, and/or placental abruption, and these disorders are potentially life-threatening to the mother and fetus. (See "Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality" and "Velamentous umbilical cord insertion and vasa previa" and "Acute placental abruption: Pathophysiology, clinical features, diagnosis, and consequences".)

Cervical status – Baseline cervical dilation and effacement should be documented so that subsequent progress (change in dilation and effacement over time) can be determined.

Station – Fetal station is expressed as the number of centimeters of the leading bony edge of the presenting part above or below the level of the ischial spines (figure 1); the maximum denominator is 5 (eg, 1 cm beyond the ischial spines corresponds to +1/5 cm). Effacement and station are shown in the figures (figure 2A-B).

Station should be documented so that subsequent progress (descent over time) can be determined.

If a cervical examination is not performed because of ruptured membranes or vaginal bleeding, engagement of the fetal head can be described in terms of fifths of the fetal head palpable above the symphysis pubis [15]. If the fetal head is not engaged (ie, three-fifths are palpable above the pelvic inlet) during labor, this should raise concerns about cephalopelvic disproportion.

Fetal lie, presentation, and position – Fetal lie, presentation, and position should also be documented. Lie refers to the long axis of the fetus relative to the longitudinal axis of the uterus; it can be longitudinal, transverse, or oblique.

Presentation refers to the fetal part that directly overlies the pelvic inlet; it is usually vertex (cephalic) or breech (figure 3A-C) but can be a shoulder, compound (eg, head and hand), or funic (umbilical cord).

Fetal position is the relationship of a nominated site of the presenting part to a denominating location on the maternal pelvis (eg, right occiput anterior). The fontanelles and suture lines of the fetal skull and their orientation according to fetal position are illustrated in the figures (figure 4 and figure 5A-C and figure 3D and figure 6). Ultrasound examination can be useful if findings on digital assessment are unclear, particularly for occiput posterior [16-18]. The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) has published practice guidelines for intrapartum ultrasound. (See "Occiput posterior position", section on 'Diagnosis'.)

Asynclitism refers to an oblique position of the fetal head where the head is tilted toward the shoulder and one of the parietal bones is the point of presentation.

Fetal size and pelvic capacity – The clinician should make an attempt to determine whether the fetus is macrosomic (usually defined as >4500 g) and may evaluate the pelvic type (figure 1); however, these assessments are poorly predictive of the newborn weight, course of labor, or success of attempted vaginal birth. (See "Shoulder dystocia: Risk factors and planning birth of high-risk pregnancies".)

Pelvimetry (ie, quantitative measurement of pelvic capacity) can be performed clinically or via imaging studies (radiography, computed tomography, magnetic resonance imaging (figure 7A-B) [19-21]). Average and critical limit values for the various parameters of the bony pelvis have been established but do not accurately predict patients at risk for cephalopelvic disproportion [22]. Routine clinical pelvimetry is not recommended [23]. Pelvimetry has been replaced, in large part, by clinical trial of the pelvis ("trial of labor").

Fetal and maternal well-being – Fetal status is assessed by the FHR pattern (see "Intrapartum fetal heart rate monitoring: Overview"). Maternal assessment is primarily directed toward identifying development of new pregnancy complications, such as preeclampsia, infection, or abruption. (See "Preeclampsia: Clinical features and diagnosis" and "Intraamniotic infection (clinical chorioamnionitis)" and "Acute placental abruption: Pathophysiology, clinical features, diagnosis, and consequences".)

Laboratory tests — Recent results from the following laboratory tests should be available. Intrapartum assessment is not always necessary if results from recent prenatal tests are available.

Hemoglobin/hematocrit – Although laboratory assessment of hemoglobin/hematocrit is commonly performed upon admission, there is no evidence that this practice is necessary in uncomplicated pregnancies. Relying on a normal hemoglobin result obtained at 26 to 28 weeks (ie, at the time of screening for gestational diabetes) appears to be a safe and acceptable approach if no major hemorrhages have occurred since the assessment [24,25].

Blood type and screen – Approximately 1 to 2 percent of patients receive a blood transfusion in the peripartum period [26,27]. There is consensus that patients at low risk of postpartum hemorrhage can be managed by holding a clot in the event that cross-matching and transfusion become necessary, patients at medium risk generally have a type and screen performed, and patients at high risk are cross-matched. In the United States, the Joint Commission recommends that hospitals use an evidence-based assessment tool for determining maternal hemorrhage risk on admission to the labor and delivery unit. Hospitals vary in the tools they use to assign a risk category. (See "Overview of postpartum hemorrhage", section on 'PPH risk assessment tools and risk-based preparation'.)

Human immunodeficiency virus (HIV) – Patients who have not had recommended HIV screening in pregnancy or whose HIV status is undocumented should have rapid HIV testing in labor if possible or, otherwise, in the immediate postpartum period, using an opt-out approach [28-32]. In the United States, some states require screening of all patients at delivery. (See "Prenatal care: Second and third trimesters", section on 'Screen for sexually transmitted infections'.)

If the rapid test is positive, then antiretroviral prophylaxis should be initiated while waiting for the results of confirmatory testing. (See "Prenatal evaluation of women with HIV in resource-rich settings" and "Antiretroviral selection and management in pregnant women with HIV in resource-rich settings".)

Hepatitis B and C – Patients who were not screened for hepatitis B surface antigen or hepatitis C virus (HCV) antibody prenatally, engage in behaviors that put them at high risk for infection (table 1), or have clinical hepatitis should be tested at hospital admission for delivery [32]. Some states require screening of all patients at delivery. (See "Prenatal care: Initial assessment", section on 'Hepatitis B' and "Prenatal care: Initial assessment", section on 'Hepatitis C'.)

If maternal hepatitis B surface antigen results are positive, the newborn is given immunoprophylaxis against hepatitis B. If maternal HCV antibody results are positive, testing for HCV antibody should be performed after 18 months of age because the results of this test in younger infants may reflect passive transfer of maternal antibody. Risks, diagnosis, and management of perinatal hepatitis infection are discussed in detail separately. (See "Hepatitis B and pregnancy" and "Vertical transmission of hepatitis C virus" and "Hepatitis C virus infection in children".)

Syphilis – Patients who engage in behaviors that put them at high risk for infection (table 1), have a fetal death after 20 weeks of gestation, or are previously untested should be screened at delivery [32]. Some states require screening of all patients at delivery. (See "Syphilis in pregnancy".)

Group B Streptococcus (GBS) – Patients with unknown GBS status can be tested with a nucleic acid amplification test (NAAT), such as polymerase chain reaction for GBS, where available. However, such testing is less reliable than routine GBS screening at 36+0 to 37+6 weeks. Chemoprophylaxis is indicated in patients with unknown GBS status if (1) NAAT is positive or (2) the patient has intrapartum risk factors for early-onset GBS infection (delivery at <37 weeks' gestation, temperature ≥100.4°F [≥38.0°C] or rupture of amniotic membranes ≥18 hours). (See "Prevention of early-onset group B streptococcal disease in neonates", section on 'Use of rapid diagnostic tests'.)

Patient preparation

Oral intake — Hydration is necessary to prevent hypovolemia, which adversely affects skeletal muscle performance and may be a factor contributing to longer duration of labor [33,34].

Patients with an adequate airway and at low risk of requiring a cesarean birth (eg, uncomplicated pregnancy, nonobese, fetal weight appropriate for gestational age, no previous cesarean, category 1 FHR tracing on admission) –We allow these patients to consume clear liquids ad libitum throughout labor, but restrict consumption of solid foods in accordance with guidelines by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia [35]. In a systematic review comparing less restrictive intrapartum oral intake policies (including solid food) with more restrictive oral intake policies (ice chips, water) in 10 randomized trials including nearly 4000 such patients, less restrictive policies resulted in a slightly shorter duration of labor (-7 to -25 minutes); however, a key outcome, aspiration rate, could not be assessed because no events occurred [36]. No other benefits or harms were noted and maternal satisfaction was not assessed.

We place a heparin lock in parturients not receiving intravenous fluids in case of an emergency necessitating parenteral medication, intravenous fluids, and/or blood transfusion.

Patients with a difficult airway or an increased risk of requiring a cesarean birth (eg, category 2 or 3 FHR tracing or other pregnancy complications) – We restrict all oral intake in these patients to reduce the risk of aspiration in the event of emergency cesarean birth under general anesthesia. Intravenous fluids are generally required to avoid hypovolemia.

Intravenous fluids — We provide maintenance intravenous fluids with 5 percent dextrose in 0.45 percent saline, normal saline, or Lactated Ringer solution [37,38]. Glucose requirements in labor are analogous to the requirement observed with sustained and vigorous exercise. Intrapartum administration of glucose avoids ketosis and also may be important for optimal myometrial function [39]. However, there is no high-quality evidence that the type and rate of intravenous infusion has a significant impact on labor duration.

Although a meta-analysis suggested that the duration of labor can be shortened by approximately one hour with administration of intravenous fluids at a rate of 250 mL/hour rather than 125 mL/hour (mean difference -64.38 minutes, 95% CI -121.88 to -6.88), the patients had unrestricted oral intake in two of the seven trials, thus data did not allow a clear conclusion as to whether beneficial effects of intravenous fluids at this rate were mitigated or eliminated in patients with unrestricted oral intake during labor [40]. In one of the only trials that compared length of labor in patients randomly assigned to 250 mL/hour of normal saline, 125 mL/hour of 5 percent dextrose in normal saline, or 250 mL/hour of 2.5 percent dextrose in normal saline with oral intake restricted to sips of water and ice chips, the length of labor was similar for all three groups [41].

Medication management

Usual daily medications – Patients can take their usual daily medications orally during labor; however, gastric absorption is unpredictable if labor is advanced. If this is a clinically important concern, a nonoral route of administration is preferable.

Glucocorticoids (other than antenatal corticosteroids for fetal lung maturation) – Patients who have been taking exogenous glucocorticoids of any dose for less than three weeks, morning prednisone (<5 mg daily or its equivalent) for any duration, or less than 10 mg of prednisone or its equivalent every other day, are unlikely to have a suppressed hypothalamic-pituitary-adrenal (HPA) axis. They should continue their usual regimen.

Patients who are currently taking prednisone >20 mg/day for three weeks or more and patients with a Cushingoid appearance are likely to have HPA axis suppression and should receive additional perioperative glucocorticoid coverage.

Patients with other doses of exogenous glucocorticoids or chronic use of inhaled or high-potency, topical glucocorticoids are more complicated. Management of these patients is described separately. (See "The management of the surgical patient taking glucocorticoids".)

GBS prophylaxis – Intrapartum chemoprophylaxis to prevent early-onset neonatal GBS infection is indicated for patients who meet standard criteria; the preferred drug is penicillin G (algorithm 1). Prevention of early-onset neonatal GBS infection, including patient selection (eg, maternal GBS colonization, previous newborn with early onset GBS disease) and antibiotic therapy are reviewed in detail separately. (See "Prevention of early-onset group B streptococcal disease in neonates".)

Interventions unlikely to be beneficial

Enemas and perineal shaving – Meta-analyses of randomized trials support avoidance of routine enemas and perineal shaving as these interventions are not beneficial and have bothersome or harmful side effects [42,43].

Bladder catheter – Patients can be encouraged to empty their bladder regularly; a urinary catheter can be uncomfortable and is unnecessary, even in patients with neuraxial anesthesia [44], unless the patient is unable to void. Available data suggest that bladder distention does not affect labor progress [45-47].

Antacids – We do not routinely administer sodium citrate to our laboring patients, but do give it to all patients before cesarean birth. Some authors have suggested universal intrapartum administration of a clear antacid (eg, 10 to 30 mL sodium citrate) since aspiration pneumonitis results from the acidity of the aspirated gastric contents; however, the utility of this approach in laboring patients has not been proven [48].

Antibiotics – Vaginal birth is not an indication for routine antibiotic prophylaxis for maternal benefit. In laboring patients at term with PROM just prior to the onset of labor or induction, antibiotics do not clearly reduce the rates of chorioamnionitis or endometritis, and may be administered at the time infection is diagnosed [49]. Antibiotic prophylaxis is not indicated in most patients with cardiac lesions, since the rate of bacteremia is low. Although two randomized trials of a single dose of oral azithromycin prophylaxis in laboring patients in Cameroon and the Gambia suggested a reduction in some maternal and infant infections compared with placebo [50,51], the data were not definitive and may not be generalizable to high-income countries. Furthermore, long-term outcomes such as changes in antibiotic resistance and effects on infant microbiomes were not assessed.

However, as discussed above, maternal administration of antibiotic prophylaxis against GBS is indicated in pregnancies in which the newborn is at risk for early-onset GBS disease (see "Prevention of early-onset group B streptococcal disease in neonates"). Prophylaxis may also be used in patients who undergo repair of a third or fourth degree laceration or manual extraction of the placenta. (See "Repair of perineal lacerations associated with childbirth", section on 'Preoperative preparation' and "Retained placenta after vaginal birth", section on 'Perform manual extraction'.)

Vaginal antiseptic antibacterial agents – Available data provide no convincing evidence to support the practice of intrapartum chlorhexidine vaginal irrigation for reducing the risk of maternal and neonatal infection [52-54]. Likewise, there are no data on the efficacy of perineal disinfection just before birth, and disinfection with povidone iodine may have adverse newborn effects [55,56].

Antispasmodics – Antispasmodics are used by obstetrical providers in some parts of the world. A systematic review found low-quality evidence that antispasmodics (eg, valethamate bromide, drotaverine hydrochloride, hyoscine butyl bromide, rociverine, camylofin dihydrochloride) reduce the duration of first stage of labor, very low-quality evidence that antispasmodics reduce the total duration of labor, and moderate quality evidence that antispasmodics do not affect the rate of normal vertex deliveries (17 trials, 2617 participants) [57].

Position — Parturients should assume positions that are comfortable [58-60]. Data from randomized trials provide no strong evidence to discourage maternal preference for choosing position during labor. In complicated pregnancies, however, specific positions may be required for maternal or fetal monitoring or for in utero resuscitation.

In a meta-analysis including 25 trials (5218 participants), the duration of the first stage was more than one hour shorter in parturients randomly assigned to upright positions (standing, sitting, kneeling, walking around) than in those randomly assigned to recumbent positions or bed care (-1.36 hours, 95% CI -2.22 to -0.51 hours) and those in upright positions had a modest reduction in cesarean birth (risk ratio [RR] 0.71, 95% CI 0.54-0.94), but there were no statistical differences in use of oxytocin augmentation (RR 0.89, 95% CI 0.76-1.05), maternal pain requiring analgesia (RR 0.95, 95% CI 0.84-1.08), or duration of the second stage (-3.71 minutes, 95% CI -9.37 to 1.94 minutes) [58]. Some serious limitations of these trials include risk of bias since blinding was not possible and the wide variation in the patients' positions and time spent in various positions.

Physical activity — Maternal preferences can guide physical activity, but parturients should be encouraged to move and ambulate freely during early labor unless there is a specific contraindication. In the largest randomized trial of walking versus staying in bed during labor (>1000 patients), walking during the first stage did not enhance or impair labor progress and had no harmful effects; however, many patients assigned to the walking group did not actually do so [61]. The meta-analysis described above (see 'Position' above) evaluated walking along with other upright positions and suggested a benefit compared with remaining in bed (eg, potentially clinically important reductions in the duration of the first stage and cesarean births) [58]. However, blinding was not possible and wide variations existed in time spent ambulating.

Pain and pain management — The first stage of labor causes visceral pain, arising from distention and ischemia of uterine and cervical tissues. Somatic pain occurs in addition to visceral pain during the second stage of labor, as the vagina, perineum, pelvic floor, and ligaments are stretched.

Labor pain produces physiologic effects, including hyperventilation and increased catecholamine levels. Such effects are usually well tolerated by healthy parturients with normal pregnancies, but may be problematic for parturients with medical comorbidities (eg, some cardiac lesions).

Continuous support — A nurturing, supportive companion during labor has obvious psychological benefits, and almost all pregnant people feel that frequent or continuous support during labor helps them cope with its challenges. Pregnant people who had a doula during labor consistently report that the doula had positive effects on their ability to cope with their childbirth and postpartum experiences and enhanced their sense of self-worth and achievement. Continuous support can also improve obstetric outcomes, as shown in the table (table 2). (See "Continuous labor support by a doula".)

Nonpharmacologic, pharmacologic, and anesthetic options — Patients should be provided with information about pain management options, ideally prior to the onset of labor, so they can make informed decisions about the choices for labor analgesia. Multiple nonpharmacologic, pharmacologic, and anesthetic options are available to help manage pain. The choice depends on patient values and preferences, unless there are medical contraindications to the method.

Nonpharmacologic approaches to labor pain management do not make pain of labor disappear, but do help the parturient better cope with the pain and maintain a sense of personal control over the birth process. (See "Nonpharmacologic approaches to management of labor pain".)

Systemic opioids can provide some pain relief, with moderate maternal satisfaction; however, side effects include nausea, vomiting, drowsiness, and rarely respiratory depression. Opioids cross the placenta and can cause decreased FHR variability and neonatal respiratory depression. As such, they are best avoided if birth is imminent.

Nitrous oxide is a nonopioid option but its efficacy for relieving labor pain is variable and less effective than neuraxial analgesia. The most common side effects are nausea and vomiting. Patients who use nitrous oxide must be monitored for respiratory depression, especially when it is administered in combination with opioids. (See "Pharmacologic management of pain during labor and delivery".)

Neuraxial analgesia is the most effective therapy for pain relief during labor and delivery. Epidural, combined spinal-epidural, and other central neuraxial techniques, including dural puncture epidural, single-shot spinal, and continuous spinal analgesia, are among the many options available to alleviate the pain of childbirth. In most cases, these techniques provide excellent analgesia with minimal risk to both mother and fetus. There is no cervical dilation that precludes administering neuraxial analgesia. (See "Neuraxial analgesia for labor and delivery (including instrumented delivery)".)

Potential side effects include hypotension, pruritus, and fever. The second stage of labor may be prolonged and there is a risk of postpartum postdural puncture headache.  

Role of amniotomy — We do not perform amniotomy routinely as there is no convincing evidence of benefit in spontaneously laboring patients with normal labor progress. Potential harms of membrane rupture include an increased risk of ascending infection and cord prolapse. Although amniotomy allows assessment of meconium passage, this information alone has poor prognostic value and does not significantly affect labor management [62,63].

In a meta-analysis of randomized trials of patients in spontaneous labor, routine amniotomy did not shorten the first or second stage or reduce the rate of cesarean birth compared with planned preservation of intact membranes (15 trials, >5500 participants) [64]. A limitation of this analysis was the lack of consistency in the timing of amniotomy with respect to cervical dilation and substantial crossover: 20 to 60 percent of patients assigned to the control group underwent amniotomy at some stage in their labor.

On the other hand, patients undergoing augmentation or induction of labor may benefit from the combination of oxytocin administration and amniotomy [65,66]. In a randomized trial not included in the meta-analysis described above, early amniotomy within one hour of the diagnosis of labor by strict criteria and oxytocin augmentation if cervical dilation was <1 cm per hour reduced the median duration of labor by 2.7 hours (from 8.9 to 6.2 hours) [65]. Amniotomy during induction is reviewed separately. (See "Induction of labor with oxytocin", section on 'Amniotomy'.)

Procedure – Amniotomy is performed transvaginally, usually with a small surgical hook or a gloved finger with a hook on it. Scratching the surface of the amniotic sac ruptures the membrane. Cord prolapse is a potential complication of membrane rupture. To reduce this risk, the head should be well-applied to the cervix before rupture, suprapubic or fundal pressure can be applied during the procedure to help maintain it there, and some clinicians perform the procedure during a contraction.

If amniotomy is performed in a patient with polyhydramnios or an unengaged or poorly applied presenting part, we suggest using a small gauge needle (rather than a hook) to puncture the fetal membranes in one or more places and performing the procedure in an operating room. This "controlled amniotomy" minimizes the risk of gushing amniotic fluid and permits emergency cesarean birth in the event of cord prolapse. A cephalic presentation should be confirmed prior to the amniotomy. (See "Umbilical cord prolapse".)

The position of the fetus and the FHR should be checked after amniotomy. With loss of the intact membrane, the fetus is more vulnerable to infection from microorganisms that may ascend from the vagina. Although rare, rupture of an unrecognized vasa previa is a potential complication.

Contraindications – Amniotomy should be avoided, if possible, in patients with active hepatitis B, hepatitis C, or HIV infection to minimize exposing the fetus to ascending infection.

Positive GBS carrier status is not a contraindication to amniotomy, if indicated. Ideally, amniotomy and other invasive procedures are performed at least four hours after intrapartum antibiotic prophylaxis has been initiated because the nadir in GBS colony counts in the amniotic and vaginal fluid is not reached until approximately three hours after the first antibiotic dose; however, these procedures should not be delayed to achieve an optimal antibiotic concentration when there is a medically or obstetrically urgent need for them. (See "Prevention of early-onset group B streptococcal disease in neonates".)

Monitoring

How often do intrapartum complications occur among low-risk parturients? — Frequent maternal-fetal assessment is important as intrapartum complications can arise rapidly even in low-risk parturients: 20 to 25 percent of all perinatal morbidity and mortality occurs in pregnancies with no underlying risk factors for adverse outcome [67] and a study of 10 million birth certificates in the United States found that 29 percent of low-risk pregnancies had at least one unexpected complication that would require nonroutine obstetric or neonatal care [68]. The lowest risk for an uncomplicated birth appears to be in multiparous parturients without a previous cesarean birth or other risk factors for complications; the risk for a complicated birth in this group was 8 to 9 percent in one large English study [69].

Fetal heart rate monitoring

Overview — Although controversial, intrapartum electronic FHR monitoring has become the most common obstetric procedure in the United States because patients and clinicians are reassured by normal results and believe there is some value in detecting abnormal FHR patterns. The benefits and harms of intrapartum FHR monitoring and the procedure for continuous and intermittent monitoring are reviewed in detail separately. (See "Intrapartum fetal heart rate monitoring: Overview".)

Continuous versus intermittent FHR monitoring – We monitor low-risk pregnancies continuously because it is more practical than intermittent monitoring in terms of nursing staff resources, but we are not rigid about this if resources permit and the patient understands the risks and benefits of intermittent monitoring and has an uncomplicated pregnancy, normal FHR tracing, and is not resting in bed. In pregnancies at increased risk of fetal compromise during labor (eg, suspected fetal growth restriction, preeclampsia, abruption, type 1 diabetes), continuous electronic FHR monitoring is standard practice [70].

Frequency of provider assessment – Ongoing clinical assessment of the FHR tracing is required. At a minimum, the American College of Obstetricians and Gynecologists (ACOG) suggests review of FHR tracings in low-risk pregnancies every 30 minutes in the first stage of labor [70].

For higher-risk pregnancies, ACOG suggests reviewing the tracing every 15 minutes in the first stage. Closer assessment and intervention may be indicated when abnormalities are identified. (See "Intrapartum category I, II, and III fetal heart rate tracings: Management".)

Documentation – The health care provider's interpretation of the tracing should be documented in the patient's medical record and should include:

Baseline FHR rate

Baseline FHR variability

Presence or absence of accelerations

Presence or absence of periodic decelerations (ie, those with contractions) or episodic decelerations (ie, those unrelated to contractions)

Changes in the FHR over time

Normal and abnormal FHR patterns — Standard definitions of FHR baseline, variability, accelerations, decelerations, and sinusoidal pattern (table 3) have been developed by the National Institute of Child Health and Human Development (NICHD) [71,72]. They are used clinically throughout the United States, and have been endorsed by ACOG [70]. The International Federation of Gynecology and Obstetrics (FIGO) published a similar consensus guideline in 2015 (FIGO2015) (table 4), which is used in many other countries [73]. (See "Intrapartum fetal heart rate monitoring: Overview", section on 'NICHD classification of FHR patterns'.)

The NICHD also introduced a three-tier FHR classification system (table 5), in which category I represents a normal tracing (predictive of normal fetal acid-base status at the time of observation), category II represents an indeterminate tracing, and category III represents an abnormal tracing (associated with an increased risk of abnormal fetal acid-base status at the time of observation) [72].

Use of the NICHD standardized approach to pattern recognition coupled with a standardized package of therapeutic interventions (table 6) can improve newborn outcome [74]. These interventions are reviewed separately. (See "Intrapartum category I, II, and III fetal heart rate tracings: Management".)

Uterine contraction monitoring — The frequency of contractions is documented as the number of contractions over a 30-minute period divided by three to give the number of contractions per 10 minutes. If this number is not a whole number, it may be rounded.

External tocodynamometry is a noninvasive means for recording contraction frequency and duration, and provides adequate information for most labors. If the tracing is inadequate, an internal pressure catheter can be placed within the uterus to measure contraction frequency, duration, and strength. (See "Use of intrauterine pressure catheters".)

Information about contraction frequency, duration, and strength can help the clinician determine the cause of abnormal labor progression and interpret abnormal FHR patterns. (See "Labor: Overview of normal and abnormal progression" and "Intrapartum category I, II, and III fetal heart rate tracings: Management".)

Normal and abnormal uterine contraction patterns

Normal contractions are regular and painful, cause progressive dilation and effacement of the cervix, and descent and eventual expulsion of the fetus.

Hypocontractile uterine activity is the most common risk factor for protraction and/or arrest disorders in the first stage of labor. The uterine activity is either not sufficiently frequent and/or strong or not appropriately coordinated to dilate the cervix and expel the fetus. (See "Labor: Overview of normal and abnormal progression", section on 'Hypocontractile uterine activity'.)

Tachysystole is defined as >5 contractions over 10 minutes averaged over 30 minutes; any number greater than 5 (eg, 5.2) should be interpreted as tachysystole. When associated with administration of oxytocin, FHR abnormalities are the most common potential consequence of tachysystole; uterine rupture is a rare complication. Management is reviewed separately. (See "Induction of labor with oxytocin", section on 'Tachysystole'.)

Monitoring the progress of labor

Frequency — Few randomized trials have evaluated the optimal frequency and timing of intrapartum vaginal examination of the cervix, fetal position, and fetal descent [75]. Furthermore, few trials have evaluated whether vaginal examination (at specific intervals or as indicated by external physical and behavioral cues) or intrapartum ultrasound examination is more useful for monitoring labor progress.

In most patients in the first stage of labor, we perform and document vaginal examinations:

On admission

At two- to four-hour intervals

Prior to administering analgesia/anesthesia (to ensure that the cervix is not fully dilated)

When the parturient feels the urge to push (to determine whether the cervix is fully dilated)

If FHR abnormalities occur (eg, to check for cord prolapse or a change in station due to uterine rupture)

The number of examinations should be kept to a minimum for patient comfort and to minimize iatrogenic infection due to exposing intrauterine contents to vaginal flora. (See "Intraamniotic infection (clinical chorioamnionitis)", section on 'Risk factors'.)

Although useful for visualizing labor progress, routine use of a partogram has not been proven to significantly improve obstetric outcome, and no partogram has been proven to be superior to others in comparative trials [76-78]. (See "Labor: Overview of normal and abnormal progression", section on 'Partogram'.)

Normal and abnormal progress — Assessing whether labor is progressing normally is a key component of intrapartum care; however, determining the onset of labor, measuring its progress, and evaluating the factors (power, passenger, pelvis) that affect its course is an inexact science. The typical duration of the first and second stage is shown in the table (table 7).

Protraction and arrest disorders are common. Approximately 20 percent of all labors ending in a live birth involve a protraction and/or arrest disorder [79]. Abnormal progress of spontaneously initiated labor may be related to uterine factors, fetal factors, the bony pelvis, or a combination of these factors (table 8) [80]. A genetic component has been purported to account for 28 percent of the susceptibility to protracted and difficult labor [81]. The risk for protraction and arrest disorders is highest in nulliparous patients with term pregnancies. Criteria for normal and abnormal progress and diagnosis and management of protracted or arrested first stage of labor are discussed in detail separately. (See "Labor: Overview of normal and abnormal progression" and "Labor: Diagnosis and management of an abnormal first stage".)

Precipitate or precipitous labor and delivery refers to a rapid labor and delivery of the fetus, variously defined as expulsion of the fetus within two to three hours of commencement of contractions. It is rare and not well studied.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Labor" and "Society guideline links: Delivery".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

Basics topics (see "Patient education: Labor and delivery (childbirth) (The Basics)" and "Patient education: How to tell when labor starts (The Basics)" and "Patient education: Managing pain during labor and delivery (The Basics)")

SUMMARY AND RECOMMENDATIONS

Creating a positive childbirth experience – Factors that are important in determining an individual's satisfaction with their childbirth experience include:

Their personal expectations and ability to cope

The amount of support they receive

The quality of the caregiver-patient relationship

Their involvement in decision-making

Minimal intervention

Childbirth education classes and the presence of a doula during labor address many of these factors. (See 'Creating a satisfactory childbirth experience' above.)

Timing of admission to the birth site – Most patients should be admitted when they enter the active phase of labor, as determined by (see 'When should the low-risk parturient be admitted?' above):

Regular contractions that require the patient's focus and attention

Significant effacement (≥80 percent)

Cervical dilation 4 to 5 cm with documented cervical change

Initial evaluation – The initial evaluation includes reviewing the prenatal record for medical or obstetric conditions that need to be addressed intrapartum, assessing development of new disorders since the last prenatal visit (eg, preeclampsia, bleeding, membrane rupture), establishing baseline cervical status so that subsequent progress can be determined, and evaluating fetal status (eg, heart rate pattern (table 3 and table 5), presentation (figure 3A-D), station (figure 2B)). (See 'Initial examination' above.)

Laboratory tests – Results from the following laboratory tests should be available at delivery: hemoglobin/hematocrit, blood type and screen, HIV, hepatitis B antigen, hepatitis C antibody, syphilis, group B Streptococcus (GBS, rectovaginal culture). (See 'Laboratory tests' above.)

Patient preparation

Fluids and oral intake – We allow patients at low risk of cesarean birth and with an adequate airway to have clear liquids ad libitum and place a heparin lock. For other patients, we provide maintenance fluids with a glucose containing crystalloid solution. There is no high-quality evidence that the type and rate of intravenous infusion has a significant impact on labor duration. (See 'Oral intake' above and 'Intravenous fluids' above.)

Activity and position – Maternal preferences should guide maternal activity and position, unless restricted by specific requirements dictated by maternal-fetal status and need for close monitoring. (See 'Physical activity' above and 'Position' above.)

Medications

-Intrapartum chemoprophylaxis to prevent early-onset neonatal GBS infection is required for patients who meet standard criteria (algorithm 1). (See "Prevention of early-onset group B streptococcal disease in neonates".)

-Usual daily medications can be taken orally; a nonoral route is preferable if delayed gastric absorption is a concern. Patients chronically receiving glucocorticoids may need a dose adjustment. (See 'Medication management' above.)

Interventions to avoid – The following interventions are not beneficial: routine enema, shaving, bladder catheter, antacids, antibiotics, vaginal antisepsis, or antispasmodics. (See 'Interventions unlikely to be beneficial' above.)

Pain management – Continuous labor support by a doula helps parturients cope with childbirth. Multiple nonpharmacologic, pharmacologic, and anesthesia options are available to help parturients manage pain during labor. (See 'Pain and pain management' above.)

Role of amniotomy – In patients in spontaneous labor, we suggest not performing amniotomy routinely (Grade 2C). There is no convincing evidence of benefit in the setting of normal labor progress, and rupture of membranes increases the risk of ascending infection and cord prolapse. In contrast, patients undergoing augmentation or induction of labor may benefit from the combination of oxytocin administration and amniotomy. (See 'Role of amniotomy' above.)

Monitoring – Intrapartum monitoring is important because complications occur in 20 to 30 percent of initially low-risk pregnancies, and can arise rapidly even in low-risk parturients.

Fetal heart rate – Intrapartum electronic fetal heart rate (FHR) monitoring is the most common obstetric procedure in the United States because patients and clinicians are reassured by normal results and believe there is some value in detecting abnormal FHR patterns.

In low-risk pregnancies, the American College of Obstetricians and Gynecologists (ACOG) suggests review and documentation of the assessment of FHR tracings every 30 minutes in the first stage of labor, at a minimum. For higher-risk pregnancies, ACOG suggests reviewing the tracing every 15 minutes in the first stage. Closer assessment and intervention (table 6) may be indicated when abnormalities are identified. (See 'Fetal heart rate monitoring' above.)

Labor progress – The number of examinations to monitor changes in cervical dilation, effacement, and fetal descent is kept to a minimum for patient comfort and to minimize iatrogenically exposing the intrauterine contents to vaginal flora.

The typical duration of the first stage is shown in the table (table 7). Approximately 20 percent of all labors ending in a live birth involve a protraction and/or arrest disorder. Abnormal progress of spontaneously initiated labor may be related to uterine factors, fetal factors, the bony pelvis, or a combination of these factors (table 8). (See 'Uterine contraction monitoring' above and 'Monitoring the progress of labor' above.)

  1. Care in normal birth: a practical guide. Technical Working Group, World Health Organization. Birth 1997; 24:121.
  2. Taheri M, Takian A, Taghizadeh Z, et al. Creating a positive perception of childbirth experience: systematic review and meta-analysis of prenatal and intrapartum interventions. Reprod Health 2018; 15:73.
  3. Chabbert M, Panagiotou D, Wendland J. Predictive factors of women's subjective perception of childbirth experience: a systematic review of the literature. J Reprod Infant Psychol 2021; 39:43.
  4. Srivastava A, Avan BI, Rajbangshi P, Bhattacharyya S. Determinants of women's satisfaction with maternal health care: a review of literature from developing countries. BMC Pregnancy Childbirth 2015; 15:97.
  5. Anderson G, Zega M, D'Agostino F, et al. Meta-Synthesis of the Needs of Women Cared for by Midwives During Childbirth in Hospitals. J Obstet Gynecol Neonatal Nurs 2021; 50:6.
  6. Vedeler C, Nilsen A, Blix E, et al. What women emphasise as important aspects of care in childbirth - an online survey. BJOG 2022; 129:647.
  7. Christiaens W, Bracke P. Assessment of social psychological determinants of satisfaction with childbirth in a cross-national perspective. BMC Pregnancy Childbirth 2007; 7:26.
  8. The American College of Obstetricians and Gynecologists Committee Opinion No. 697: Planned home birth. Available at: https://www.acog.org/-/media/Committee-Opinions/Committee-on-Obstetric-Practice/co697.pdf?dmc=1&ts=20170506T1034060833 (Accessed on March 21, 2018). Reaffirmed 2018.
  9. Campbell K, Carson G, Azzam H, Hutton E. No. 372-Statement on Planned Homebirth. J Obstet Gynaecol Can 2019; 41:223.
  10. Lagrew DC, Low LK, Brennan R, et al. National Partnership for Maternal Safety: Consensus Bundle on Safe Reduction of Primary Cesarean Births-Supporting Intended Vaginal Births. Obstet Gynecol 2018; 131:503.
  11. Obstetrics Care Workgroup. Obstetrics care topic report and recommendations. In: Quinn R, editor. Seattle (WA): Dr. Robert Bree Collaborative; 2012.
  12. Kauffman E, Souter VL, Katon JG, Sitcov K. Cervical Dilation on Admission in Term Spontaneous Labor and Maternal and Newborn Outcomes. Obstet Gynecol 2016; 127:481.
  13. Nelson DB, McIntire DD, Leveno KJ. False Labor at Term in Singleton Pregnancies: Discharge After a Standardized Assessment and Perinatal Outcomes. Obstet Gynecol 2017; 130:139.
  14. Sandall J, Soltani H, Gates S, et al. Midwife-led continuity models versus other models of care for childbearing women. Cochrane Database Syst Rev 2016; 4:CD004667.
  15. Department of Reproductive Health and Research. Managing complications in pregnancy and childbirth: a guide for midwives and doctors. World Health Organization, Geneva, reprinted 2007.
  16. Chou MR, Kreiser D, Taslimi MM, et al. Vaginal versus ultrasound examination of fetal occiput position during the second stage of labor. Am J Obstet Gynecol 2004; 191:521.
  17. Kreiser D, Schiff E, Lipitz S, et al. Determination of fetal occiput position by ultrasound during the second stage of labor. J Matern Fetal Med 2001; 10:283.
  18. Youssef A, Ghi T, Pilu G. How to perform ultrasound in labor: assessment of fetal occiput position. Ultrasound Obstet Gynecol 2013; 41:476.
  19. van Loon AJ, Mantingh A, Serlier EK, et al. Randomised controlled trial of magnetic-resonance pelvimetry in breech presentation at term. Lancet 1997; 350:1799.
  20. Raman S, Samuel D, Suresh K. A comparative study of X-ray pelvimetry and CT pelvimetry. Aust N Z J Obstet Gynaecol 1991; 31:217.
  21. Zaretsky MV, Alexander JM, McIntire DD, et al. Magnetic resonance imaging pelvimetry and the prediction of labor dystocia. Obstet Gynecol 2005; 106:919.
  22. Pattinson RC, Cuthbert A, Vannevel V. Pelvimetry for fetal cephalic presentations at or near term for deciding on mode of delivery. Cochrane Database Syst Rev 2017; 3:CD000161.
  23. WHO recommendations: intrapartum care for a positive childbirth experience. Geneva: World Health Organization; 2018. Licence: CC BY-NC-SA 3.0 IGO.
  24. Sherard GB 3rd, Newton ER. Is routine hemoglobin and hematocrit testing on admission to labor and delivery needed? Obstet Gynecol 2001; 98:1038.
  25. Ries LT, Kopelman JN, Macri CI. Evaluation of routine antepartum and postpartum blood counts. J Reprod Med 1998; 43:581.
  26. Trends and Disparities in Delivery Hospitalizations Involving Severe Maternal Morbidity, 2006-2015. Healthcare Cost and Utilization Project (HCUP). Available at: http://www.hcup-us.ahrq.gov/reports/statbriefs/sb243-Severe-Maternal-Morbidity-Delivery-Trends-Disparities.jsp (Accessed on October 03, 2018).
  27. Patterson JA, Nippita T, Randall DA, et al. Outcomes of subsequent pregnancy following obstetric transfusion in a first birth. PLoS One 2018; 13:e0203195.
  28. ACOG Committee Opinion No. 751: Labor and Delivery Management of Women With Human Immunodeficiency Virus Infection. Obstet Gynecol 2018; 132:e131.
  29. ACOG Committee Opinion No. 752: Prenatal and Perinatal Human Immunodeficiency Virus Testing. Obstet Gynecol 2018; 132:e138.
  30. US Preventive Services Task Force, Owens DK, Davidson KW, et al. Screening for HIV Infection: US Preventive Services Task Force Recommendation Statement. JAMA 2019; 321:2326.
  31. Selph SS, Bougatsos C, Dana T, et al. Screening for HIV Infection in Pregnant Women: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA 2019; 321:2349.
  32. Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep 2021; 70:1.
  33. Maughan RJ, Bethell LR, Leiper JB. Effects of ingested fluids on exercise capacity and on cardiovascular and metabolic responses to prolonged exercise in man. Exp Physiol 1996; 81:847.
  34. Montain SJ, Coyle EF. Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. J Appl Physiol (1985) 1992; 73:1340.
  35. Practice Guidelines for Obstetric Anesthesia: An Updated Report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2016; 124:270.
  36. Ciardulli A, Saccone G, Anastasio H, Berghella V. Less-Restrictive Food Intake During Labor in Low-Risk Singleton Pregnancies: A Systematic Review and Meta-analysis. Obstet Gynecol 2017; 129:473.
  37. Shrivastava VK, Garite TJ, Jenkins SM, et al. A randomized, double-blinded, controlled trial comparing parenteral normal saline with and without dextrose on the course of labor in nulliparas. Am J Obstet Gynecol 2009; 200:379.e1.
  38. Jamal A, Choobak N, Tabassomi F. Intrapartum maternal glucose infusion and fetal acid-base status. Int J Gynaecol Obstet 2007; 97:187.
  39. Riegel M, Quist-Nelson J, Saccone G, et al. Dextrose intravenous fluid therapy in labor reduces the length of the first stage of labor. Eur J Obstet Gynecol Reprod Biol 2018; 228:284.
  40. Ehsanipoor RM, Saccone G, Seligman NS, et al. Intravenous fluid rate for reduction of cesarean delivery rate in nulliparous women: a systematic review and meta-analysis. Acta Obstet Gynecol Scand 2017; 96:804.
  41. Fong A, Serra AE, Caballero D, et al. A randomized, double-blinded, controlled trial of the effects of fluid rate and/or presence of dextrose in intravenous fluids on the labor course of nulliparas. Am J Obstet Gynecol 2017; 217:208.e1.
  42. Reveiz L, Gaitán HG, Cuervo LG. Enemas during labour. Cochrane Database Syst Rev 2013; :CD000330.
  43. Basevi V, Lavender T. Routine perineal shaving on admission in labour. Cochrane Database Syst Rev 2014; :CD001236.
  44. Dempsey A, Krening C, Vorgic L. Multisite Randomized Controlled Trial of Bladder Management in Labor With Epidural Analgesia/Anesthesia. J Obstet Gynecol Neonatal Nurs 2020; 49:564.
  45. Kerr-Wilson RH, Parham GP, Orr JW Jr. The effect of a full bladder on labor. Obstet Gynecol 1983; 62:319.
  46. Read JA, Miller FC, Yeh S, Platt LD. Urinary bladder distention: effect on labor and uterine activity. Obstet Gynecol 1980; 56:565.
  47. Evron S, Dimitrochenko V, Khazin V, et al. The effect of intermittent versus continuous bladder catheterization on labor duration and postpartum urinary retention and infection: a randomized trial. J Clin Anesth 2008; 20:567.
  48. Gyte GM, Richens Y. Routine prophylactic drugs in normal labour for reducing gastric aspiration and its effects. Cochrane Database Syst Rev 2006; :CD005298.
  49. Saccone G, Berghella V. Antibiotic prophylaxis for term or near-term premature rupture of membranes: metaanalysis of randomized trials. Am J Obstet Gynecol 2015; 212:627.e1.
  50. Subramaniam A, Ye Y, Mbah R, et al. Single Dose of Oral Azithromycin With or Without Amoxicillin to Prevent Peripartum Infection in Laboring, High-Risk Women in Cameroon: A Randomized Controlled Trial. Obstet Gynecol 2021; 138:703.
  51. Oluwalana C, Camara B, Bottomley C, et al. Azithromycin in Labor Lowers Clinical Infections in Mothers and Newborns: A Double-Blind Trial. Pediatrics 2017; 139.
  52. Lumbiganon P, Thinkhamrop J, Thinkhamrop B, Tolosa JE. Vaginal chlorhexidine during labour for preventing maternal and neonatal infections (excluding Group B Streptococcal and HIV). Cochrane Database Syst Rev 2014; :CD004070.
  53. Ohlsson A, Shah VS, Stade BC. Vaginal chlorhexidine during labour to prevent early-onset neonatal group B streptococcal infection. Cochrane Database Syst Rev 2014; :CD003520.
  54. Wiysonge CS, Shey MS, Shang JD, et al. Vaginal disinfection for preventing mother-to-child transmission of HIV infection. Cochrane Database Syst Rev 2005; :CD003651.
  55. Li H, Chen S, Wu L, et al. The effects of perineal disinfection on infant's oral microflora after transvaginal examination during delivery. BMC Pregnancy Childbirth 2019; 19:213.
  56. Arena Ansotegui J, Emparanza Knörr JI, San Millán Vege MJ, et al. [Iodine overload in newborn infants caused by the use of PVP-iodine for perineal preparation of the mother in vaginal delivery]. An Esp Pediatr 1989; 30:23.
  57. Rohwer AC, Khondowe O, Young T. Antispasmodics for labour. Cochrane Database Syst Rev 2013; :CD009243.
  58. Lawrence A, Lewis L, Hofmeyr GJ, Styles C. Maternal positions and mobility during first stage labour. Cochrane Database Syst Rev 2013; :CD003934.
  59. Gupta JK, Sood A, Hofmeyr GJ, Vogel JP. Position in the second stage of labour for women without epidural anaesthesia. Cochrane Database Syst Rev 2017; 5:CD002006.
  60. Walker KF, Kibuka M, Thornton JG, Jones NW. Maternal position in the second stage of labour for women with epidural anaesthesia. Cochrane Database Syst Rev 2018; 11:CD008070.
  61. Bloom SL, McIntire DD, Kelly MA, et al. Lack of effect of walking on labor and delivery. N Engl J Med 1998; 339:76.
  62. Locatelli A, Regalia AL, Patregnani C, et al. Prognostic value of change in amniotic fluid color during labor. Fetal Diagn Ther 2005; 20:5.
  63. Greenwood C, Lalchandani S, MacQuillan K, et al. Meconium passed in labor: how reassuring is clear amniotic fluid? Obstet Gynecol 2003; 102:89.
  64. Smyth RM, Markham C, Dowswell T. Amniotomy for shortening spontaneous labour. Cochrane Database Syst Rev 2013; :CD006167.
  65. Frigoletto FD Jr, Lieberman E, Lang JM, et al. A clinical trial of active management of labor. N Engl J Med 1995; 333:745.
  66. De Vivo V, Carbone L, Saccone G, et al. Early amniotomy after cervical ripening for induction of labor: a systematic review and meta-analysis of randomized controlled trials. Am J Obstet Gynecol 2020; 222:320.
  67. Zapata-Vázquez RE, Rodríguez-Carvajal LA, Sierra-Basto G, et al. Discriminant function of perinatal risk that predicts early neonatal morbidity: its validity and reliability. Arch Med Res 2003; 34:214.
  68. Danilack VA, Nunes AP, Phipps MG. Unexpected complications of low-risk pregnancies in the United States. Am J Obstet Gynecol 2015; 212:809.e1.
  69. Jardine J, Blotkamp A, Gurol-Urganci I, et al. Risk of complicated birth at term in nulliparous and multiparous women using routinely collected maternity data in England: cohort study. BMJ 2020; 371:m3377.
  70. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 106: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. Obstet Gynecol 2009; 114:192. Reaffirmed 2021.
  71. Electronic fetal heart rate monitoring: research guidelines for interpretation. National Institute of Child Health and Human Development Research Planning Workshop. Am J Obstet Gynecol 1997; 177:1385.
  72. Macones GA, Hankins GD, Spong CY, et al. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines. Obstet Gynecol 2008; 112:661.
  73. Ayres-de-Campos D, Spong CY, Chandraharan E, FIGO Intrapartum Fetal Monitoring Expert Consensus Panel. FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography. Int J Gynaecol Obstet 2015; 131:13.
  74. Clark SL, Meyers JA, Frye DK, et al. Recognition and response to electronic fetal heart rate patterns: impact on newborn outcomes and primary cesarean delivery rate in women undergoing induction of labor. Am J Obstet Gynecol 2015; 212:494.e1.
  75. Moncrieff G, Gyte GM, Dahlen HG, et al. Routine vaginal examinations compared to other methods for assessing progress of labour to improve outcomes for women and babies at term. Cochrane Database Syst Rev 2022; 3:CD010088.
  76. Lavender T, Cuthbert A, Smyth RM. Effect of partograph use on outcomes for women in spontaneous labour at term and their babies. Cochrane Database Syst Rev 2018; 8:CD005461.
  77. Bonet M, Oladapo OT, Souza JP, Gülmezoglu AM. Diagnostic accuracy of the partograph alert and action lines to predict adverse birth outcomes: a systematic review. BJOG 2019; 126:1524.
  78. Myers ER, Sanders GD, Coeytaux RR, et al. Labor Dystocia. Comparative Effectiveness Review No. 226. (Prepared by the Duke Evidence-based Practice Center under Contract No. 290-2015-00004-I.) AHRQ Publication No. 29-EHC007. Rockville, MD: Agency for Healthcare Research and Quality; May 2020. DOI: https://doi.org/10.23970/AHRQEPCCER226.
  79. Zhu BP, Grigorescu V, Le T, et al. Labor dystocia and its association with interpregnancy interval. Am J Obstet Gynecol 2006; 195:121.
  80. Myles TD, Santolaya J. Maternal and neonatal outcomes in patients with a prolonged second stage of labor. Obstet Gynecol 2003; 102:52.
  81. Algovik M, Nilsson E, Cnattingius S, et al. Genetic influence on dystocia. Acta Obstet Gynecol Scand 2004; 83:832.
Topic 4445 Version 211.0

References