Cesarean birth: Preoperative planning and patient preparation

INTRODUCTION — Cesarean birth (also called cesarean section) is one of the most common major surgical procedures performed in an operating room in the United States. Cesarean births comprise almost one-third of births in the United States [1]. It is also a common procedure in many countries worldwide, and the rate is generally rising [2]. Concerns about the rising rate have prompted medical organizations to suggest potential interventions to reduce the rate of unnecessary procedures, such as education, standardization, better childbirth preparation, second opinion before/peer review after a cesarean, broader midwifery-led care, more trials of labor after a cesarean, continuous labor support, multifaceted toolkits, changes in current financial incentives/disincentives, and process measures with rapid feedback [3-6]. There is some evidence that implementation of a multifaceted approach to support vaginal birth can be effective in reducing cesarean births in nulliparous, term, singleton, vertex pregnancies [7].

This topic will review preoperative planning and patient preparation for cesarean birth. Surgical technique, postoperative issues, repeat cesarean birth, cesarean birth on maternal request, and trial of labor after cesarean birth are discussed separately:

●(See "Cesarean birth: Surgical technique".)

●(See "Cesarean birth: Postoperative care, complications, and long-term sequelae".)

●(See "Repeat cesarean birth".)

●(See "Cesarean birth on patient request".)

●(See "Choosing the route of delivery after cesarean birth".)

Our approach is generally consistent with other evidenced-based protocols. The Enhanced Recovery After Surgery (ERAS) Society has published guidelines for perioperative care of patients undergoing cesarean birth, the ERAS Cesarean Delivery Guidelines, which cover the time from decision to operate (starting with the 30 to 60 minutes before skin incision) to hospital discharge [8-10]. The American College of Obstetricians and Gynecologists has published a guideline for enhanced recovery after surgery [11]. Other organizations and many hospitals have also created such guidelines/pathways [12]. These approaches appear to reduce postoperative complications, reduce postoperative pain scores and opioid use, and shorten hospital stay without compromising readmission rates [13-15]. However, guidelines vary and their recommendations are often based on expert opinion and evidence from observational studies.

INDICATIONS — Cesarean birth is performed when the clinician and/or patient believe that abdominal birth is likely to provide a better maternal and/or fetal outcome than vaginal birth. Thus, indications for cesarean birth fall into two general categories:

●Medically/obstetrically indicated

●On maternal request

Approximately 70 percent of cesarean births in the United States are primary (first) cesareans. The three most common indications for primary cesarean birth in the United States account for almost 80 percent of these births [16]:

●Failure to progress during labor (35 percent)

●Nonreassuring fetal status (24 percent)

●Fetal malpresentation (19 percent)

Additionally, less common indications for primary cesarean birth include, but are not limited to:

●Abnormal placentation (eg, placenta previa, placenta accreta spectrum, vasa previa)

●Maternal infection with significant risk of perinatal transmission during vaginal birth

●Some fetal bleeding diatheses

●Funic (cord) presentation or cord prolapse

●Suspected macrosomia (typically 5000 grams in patients without diabetes, 4500 grams in patients with diabetes)

●Mechanical obstruction to vaginal birth (eg, large fibroid, severely displaced pelvic fracture, severe fetal hydrocephalus)

●Uterine rupture

●Prior extensive transmyometrial uterine surgery, such as some myomectomies and reconstructive surgeries used to repair congenital uterine anomalies

Although infrequent, cesarean birth is also indicated in patients who are at increased risk for complications/injury from cervical dilation, descent and expulsion of the fetus, or episiotomy. Some examples include patients with invasive cervical cancer, active perianal inflammatory bowel disease, or history of repair of a rectovaginal fistula or pelvic organ prolapse. (See "Cervical cancer in pregnancy" and "Fertility, pregnancy, and nursing in inflammatory bowel disease" and "Effect of pregnancy and childbirth on urinary incontinence and pelvic organ prolapse" and "Fecal and anal incontinence associated with pregnancy and childbirth: Counseling, evaluation, and management".)

Cesarean birth on maternal request is uncommon, and discussed separately. (See "Cesarean birth on patient request".)

Cesarean birth is not routinely indicated for low birth weight (see "Delivery of the low birth weight singleton cephalic fetus"), twin pregnancies (see "Twin pregnancy: Labor and delivery"), and most congenital anomalies. (Refer to topic reviews on individual anomalies.)

CONTRAINDICATIONS — There are no absolute contraindications to cesarean birth. In contrast to other types of surgery, the risks and benefits of the procedure are considered as they apply to two patients (mother and fetus). However, many pregnant individuals have a low tolerance for accepting any fetal risk from vaginal birth, irrespective of the maternal risks associated with cesarean birth [17,18].

PREOPERATIVE PLANNING

Patient education/consent — Good clinical practice involves counseling the patient about the procedure and the plan for their care before, during, and after the cesarean birth. A consent form for the procedure should be reviewed, including basic procedural information, risks, and benefits; all questions should be answered prior to signing. This information may diminish anxiety, help patients make well-informed choices relating to their care, and enhance postoperative recovery. (See "Informed consent in obstetrics".)

As part of patient education, implications for future pregnancies should be discussed. These issues are reviewed separately. (See "Repeat cesarean birth".)

Checklists — Checklists can be helpful in preoperative planning and are available from various organizations, such as the American College of Obstetricians and Gynecologists and Agency for Healthcare Research and Quality (AHRQ).

Postpartum contraception — Postpartum contraception plans should be discussed during prenatal care, and decisions made well before the intrapartum period. (See "Contraception: Postpartum counseling and methods".)

For patients who are certain that they desire permanent contraception, the procedure can be performed at the time of cesarean birth. (See "Overview of female permanent contraception" and "Postpartum permanent contraception: Procedures", section on 'Following cesarean birth'.)

Scheduling

●Medically or obstetrically indicated procedures — Medically/obstetrically indicated cesarean births are scheduled when clinically indicated. Indications for administration of a course of antenatal corticosteroids before preterm birth, if time permits, are reviewed separately. (See "Antenatal corticosteroid therapy for reduction of neonatal respiratory morbidity and mortality from preterm delivery", section on 'Candidates for a first ACS course by gestational age'.)

When a primary cesarean birth is indicated for maternal or fetal reasons, but preterm birth is not indicated, there is consensus that planned term cesarean birth should be scheduled in the 39^th week of gestation [19-21]. We caution against performing early term (in the 37^th or 38^th week of gestation) cesareans when the medical/obstetric indication for delivery is "soft," such as a history of fetal, maternal, or obstetric complication in a previous pregnancy that has not recurred.

In suboptimally dated pregnancies, scheduling should be based on the best clinical estimate of gestational age [22]. Performing an amniocentesis for assessment of fetal lung maturity is not recommended as a component of this decision and is rarely, if ever, clinically indicated.

This approach is based on data from large, observational studies and randomized trials that consistently show that neonatal respiratory morbidity and/or composite neonatal morbidity is higher after planned cesarean birth and decreases as gestational age increases from 37 to 40 weeks [23-31]. An example of the magnitude of these risks was provided by a study that evaluated adverse neonatal outcomes according to completed week of gestation in over 13,000 elective cesareans performed before the onset of labor [32]. Birth before 39 weeks of gestation was associated with a statistically higher risk of respiratory and other adverse neonatal outcomes compared with birth at or after 39 weeks of gestation:

•Rates of respiratory distress syndrome/transient tachypnea by gestational age were: 37 weeks (8.2 percent), 38 weeks (5.5 percent), 39 weeks (3.4 percent), 40 weeks (3 percent), and 41 weeks (5.2 percent)

•Rates of any adverse outcome/death by gestational were: 37 weeks (15.3 percent), 38 weeks (11 percent), 39 weeks (8 percent), 40 weeks (7.3 percent), and 41 weeks (11.3 percent)

●Planned repeat cesarean birth — Timing of planned repeat cesarean birth is based on the type of previous hysterotomy incision and is reviewed separately. (See "Repeat cesarean birth", section on 'Timing'.)

●Cesarean birth on maternal request — Cesarean birth on maternal request is planned for the 39^th week of gestation. (See "Cesarean birth on patient request".)

Natural, gentle, or family-centered cesarean — The "natural," "gentle," or "family-centered" cesarean birth approach was developed to improve the birth experience of patients having uncomplicated cesarean births. It attempts to replicate features of vaginal birth as much as possible to make cesarean surgery more family friendly. Components of this approach may include [33,34]:

●Reduction of extraneous noise (eg, conversation among staff) and playing background music of the parent(s)' choice during birth.

●Dimming lights, when safely possible.

●Using clear drapes or positioning the drapes to allow the parent(s) to watch the birth.

●Avoiding maternal sedation.

●Allowing the newborn to be born by a combination of natural uterine expulsion and active physician assistance to mimic expulsion from the vagina.

●Freeing the mother's dominant hand/arm and chest/breasts from lines and monitors, when possible, so they can hold and nurse the newborn.

●Promoting skin-to-skin contact and nursing immediately after birth.

Family-centered cesarean is preferred whenever feasible (ie, routinely unless an emergency cesarean needs to be performed). The parent(s) become an active part of the cesarean birth by directly observing the birth and by cutting the umbilical cord. In a randomized trial, family-centered cesarean was safe for both mother and newborn and led to a better birth experience, higher rate of breastfeeding, and improved early mother-infant interaction [35].

Intrapartum cesarean — Intrapartum cesarean births are sometimes classified by degree of urgency; for example: (1) an immediate threat to life of the mother or fetus is present, (2) signs of maternal or fetal compromise are present but are not immediately life threatening, or (3) delivery is needed, but there is no evidence of maternal or fetal compromise. Compared with planned cesarean birth, intrapartum cesarean is associated with increased risks of postpartum hemorrhage, anesthetic complications from rapid administration of general anesthesia, and accidental injury to the fetus or abdominopelvic organs.

Although, historically, facilities providing obstetric services were asked to be capable of beginning an intrapartum cesarean birth within 30 minutes of the decision to perform the operation, this threshold was based upon the practical constraints many hospitals faced in assembling the appropriate team of nurses, anesthetists, and surgeons. The threshold was not evidence-based, universally achievable, or ideal from the perspective of decreasing perinatal or maternal mortality and morbidity [36-45].

The ability to begin an intrapartum cesarean birth within 30 minutes of the decision to operate is a reasonable benchmark for monitoring the quality of labor and delivery units, but not a requirement that all cesarean births be performed within 30 minutes of the decision. In human and animal studies, sudden complete anoxia, such as occurs with a total abruption or complete cord occlusion, probably necessitates delivery within five minutes to avoid fetal hypoxia [46-48], although intact survivors have been reported after longer durations of severe hypoxia. Most pregnancies with less severe fetal or maternal compromise or partial or complete recovery of nonreassuring fetal heart rate tracings will have good outcomes despite intervals over 30 minutes before initiating surgery [45].

PREPROCEDURE MATERNAL PREPARATIONS

Skin self-cleansing — A Centers for Disease Control (CDC) guideline for the prevention of surgical site infection suggests that patients shower or bathe (full body) with soap (nonantimicrobial or antimicrobial) or an antiseptic agent on at least the night before the day of any surgery [49]. We do not advise patients to use any particular product to cleanse their skin before cesarean. A placebo-controlled randomized trial of pregnant individuals undergoing cesarean birth failed to show benefit with chlorhexidine [50]. Meta-analyses of randomized trials of preoperative bathing or showering with chlorhexidine or other products before a variety of other surgical procedures have also found no clear reduction in surgical site infection rates [51-54].

Skin preparation in the operating room is discussed below. (See 'Skin preparation' below.)

Fasting and aspiration prophylaxis — Preoperative fasting (eg, two-hour fast for clear liquids, six-hour fast for solids, eight-hour fast for fatty meals before surgery but encourage clear liquids up to two hours before surgery) and administration of pharmacologic prophylaxis are reviewed separately. (See "Anesthesia for cesarean delivery", section on 'Preparation for anesthesia'.)

Some guidelines suggest that the clear liquids contain carbohydrate (eg, apple juice, Gatorade) in patients without diabetes [12]. Encouraging fluids up to two hours prior to surgery and carbohydrate loading (45 grams is suggested) are thought to reduce preoperative anxiety, hypoglycemia, dehydration, thirst, and hunger. (See "Preoperative fasting in adults".)

Anesthesia consultation — As with any surgical procedure, patients undergoing cesarean birth should have a preoperative consultation with the anesthesia team. Those whose procedure-related risks are above baseline should have a preadmission consultation, if possible. Characteristics that place the patient at increased risk may include, but are not limited to, those listed in the table (table 1).

The choice of regional or general anesthesia is influenced by factors such as the urgency of the procedure, maternal status and comorbid conditions, and physician and patient preference. Issues related to anesthesia for cesarean birth, including preanesthetic medications (eg, antacids, histamine H2 receptor antagonists) and oral intake, are discussed in detail separately. (See "Anesthesia for cesarean delivery".)

Laboratory testing — A baseline hemoglobin or hematocrit measurement is recommended for patients who are undergoing major surgery, such as cesarean birth, that is expected to result in significant blood loss. A value in the normal range obtained within one month of surgery probably does not need to be repeated preoperatively in uncomplicated pregnancies. (See "Preoperative medical evaluation of the healthy adult patient".)

In the United States, The Joint Commission requires use of an evidence-based tool for determining maternal hemorrhage risk on admission to labor and delivery [55]. Based on assessment of low, medium, or high risk of hemorrhage, blood is sent to the blood bank for holding in readiness, type and screen, or crossmatch, respectively. Methods of risk assessment and preparation for postpartum hemorrhage, a relatively common life-threatening emergency, are integral components of intrapartum care and reviewed separately. (See "Overview of postpartum hemorrhage".)

Antibiotic prophylaxis

Regimen — For all patients not already on antibiotics and undergoing cesarean birth, we administer:

●Cefazolin in the 60 minutes before making the skin incision [56]:

•<120 kg – 2 g intravenously (IV)

•≥120 kg – 3 g IV

●PLUS a single dose of azithromycin 500 mg intravenously for patients in labor or with ruptured membranes [57].

●PLUS antiseptic abdominal and vaginal cleansing preparation. (See 'Skin preparation' below and 'Vaginal preparation' below.)

The American College of Obstetricians and Gynecologists (ACOG) also recommends a single dose of a first-generation cephalosporin, but dosing is different (cefazolin 1 g IV for patients <80 kg, 2 to 3 g IV for patients ≥80 kg) [58]. ACOG states that azithromycin may be considered in unplanned cesareans.

Evidence

●Benefits – In the absence of antimicrobial prophylaxis, patients undergoing cesarean birth have a 5- to 20-fold greater risk for infection compared with those who give birth vaginally [59]. The benefit of antibiotic prophylaxis before cesarean birth was illustrated in a systematic review of randomized trials that compared maternal outcomes "with" versus "without" use of prophylactic antibiotics and found that antibiotic prophylaxis reduced the risk of endometritis by approximately 60 percent in both antepartum and intrapartum cesarean births (95 trials, >15,000 participants) [59]. The risks of wound infection, urinary tract infection, and serious maternal infectious complications were also reduced. In a smaller systematic review that evaluated neonatal outcomes (12 trials, >5000 participants), nonstatistically significant reductions in neonatal sepsis (risk ratio [RR] 0.76, 95% CI 0.51-1.13) and neonatal infection with antimicrobial-resistant bacteria (RR 0.70, 95% CI 0.32-4.14) were reported, and would be clinically important if proven true when more robust data become available [60].

Although the relative risk reduction in maternal infection is statistically significant and similar for both antepartum and intrapartum procedures, the absolute risk of maternal infection is quite low in antepartum cases: In a large observational study, postpartum endometritis occurred in 2 percent of patients with antibiotic prophylaxis versus 2.6 percent without antibiotic prophylaxis; wound infection occurred in 0.52 percent of patients with antibiotic prophylaxis versus 0.96 percent without antibiotic prophylaxis [61]. Thus, 1000 patients undergoing antepartum cesarean birth would receive antibiotics to prevent 6 cases of endometritis and 4.4 cases of abdominal wound infection. The low risk of maternal infection in these cases and uncertainty about long-term effects in offspring have prompted a call for more research on potential long-term risks of exposure to antibiotic prophylaxis and strategies for risk stratification to identify the best candidates for antibiotic prophylaxis [62]. Until these data are available, we administer antibiotics before all cesarean births, in accordance with ACOG guidelines [58].

●Timing – Antimicrobial therapy should be administered within 60 minutes before making the skin incision to ensure adequate drug tissue levels [58]. This recommendation is supported by a meta-analysis of randomized trials that compared infection rates in pregnant patients assigned to a single pre-incision dose of antibiotic prophylaxis versus those assigned to administration after cord clamping [60]. Pre-incision prophylaxis was significantly more effective than delayed administration for prevention of endometritis (RR 0.54, 95% CI 0.36-0.79) and was not associated with an increase in proven neonatal sepsis, sepsis work-ups, or admission to the neonatal intensive care unit, although the trials had limited power to detect adverse neonatal effects. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Timing'.)

●Drug choice and dose – Comparative trials do not provide strong evidence on which to base a recommendation for the optimal drug and dose.

•Broad spectrum single antibiotics – Based on expert opinion from infectious disease experts, we administer cefazolin, with dosing based on weight [56]. The higher dose for patients with obesity is based on pharmacokinetic data rather than surgical site infection rates, and these data have been inconsistent [63-67]. Cefazolin has a longer half-life than ampicillin (1.8 versus 0.7 to 1.5 hours in adults with normal renal function [68]), which is an advantage in long surgeries. In a 2021 systematic review of randomized trials, first- and second-generation cephalosporins (eg, cefazolin, cefoxitin) and broad-spectrum penicillins plus betalactamase inhibitors (eg, amoxicillin plus clavulanic acid, ampicillin plus sulbactam) appeared to be similarly effective for preventing postoperative maternal infection (endometritis, wound infection) after cesarean birth; use of adjunctive azithromycin to target Ureaplasma and Mycoplasma species was not evaluated [69]. Other systematic reviews of randomized trials have noted that a single dose of antibiotics is as effective as multiple doses [70,71].

•Extended-spectrum antibiotic combinations – Additional data from randomized trials support use of extended-spectrum antibiotic combinations (eg, cefazolin plus azithromycin, cefazolin plus metronidazole) for women at high risk of post-cesarean infection [72]. In a seminal placebo-controlled multicenter randomized trial including over 2000 pregnant patients, administration of azithromycin 500 mg intravenously before skin incision in addition to preoperative cefazolin resulted in a 50 percent reduction in the composite outcome of endometritis, wound infection, or other infection (endometritis 3.8 versus 6.1 percent, wound infection 2.4 versus 6.6 percent; composite RR 0.51, 95% CI 0.38-0.68), without impacting the frequency of adverse neonatal outcomes [57]. The authors also found that adjunctive azithromycin prophylaxis was cost-effective [73]. Of note, only patients who had a cesarean birth during labor or at least four hours after rupture of membranes were included, so these data do not apply to other cesarean births (eg, antepartum cesarean births with intact membranes). Specific tests for Ureaplasma or Mycoplasma species were not routinely performed, thus it is not known whether coverage against Ureaplasma and Mycoplasma species provided by the extended antibiotic regimen accounted for the reduction in postoperative infection.

Ideally, azithromycin is infused within the 60 minutes before making the skin incision, but this may not be possible intrapartum. In the trial discussed above, the drug appeared to be effective regardless of timing of administration; 83 percent of patients received azithromycin 0 to 60 minutes before the skin incision, 5 percent received it >60 minutes before the incision, and 12 percent received it after the incision was made [57]. In a secondary analysis of these data, azithromycin administration was associated with a reduced risk of maternal postcesarean infection when administered within 60 minutes before skin incision and when administered after (median 3 minutes, range 0–229 minutes) skin incision [74]. 

Observational studies evaluating the use of azithromycin prophylaxis of prelabor cesarean births in patients with intact membranes have reported discordant results [75,76]. No adequately powered randomized trial has evaluated adding azithromycin to cefazolin in this setting. Therefore, we continue to only use cefazolin for prophylaxis in patients with intact membranes not in labor.

●Duration – Traditionally, prophylaxis has not been continued postpartum because studies in general surgical populations showed no benefit from postoperative antimicrobial prophylaxis. However, one trial in patients with obesity undergoing cesarean birth reported a benefit of antibiotic prophylaxis for 48 hours following the cesarean when given in addition to preoperative prophylaxis. These data are discussed in detail separately. (See "Cesarean birth: Overview of issues for patients with obesity", section on 'Antibiotic prophylaxis'.)

Special populations

Patients with penicillin allergy — These patients fall into two groups: those with previous serious reactions and those at low risk for a serious reaction.

●For patients with a history of serious forms of penicillin allergy, we suggest a single dose of combination therapy [56,58]

Antepartum cesarean with intact membranes:

•Clindamycin 900 mg IV plus

•Gentamicin 5 mg/kg IV

Intrapartum cesarean or after rupture of membranes:

•Add azithromycin 500 mg IV to the combination above

Serious forms of penicillin allergy include immediate reactions (ie, anaphylactic) (table 2), as well several types of delayed reactions (Stevens-Johnson syndrome [SJS], toxic epidermal necrolysis [TEN], drug rash eosinophilia systemic symptoms [DRESS], drug-induced liver or other organ injury, and drug-induced cytopenias).

When gentamicin is used for prophylaxis in combination with a parenteral antimicrobial with activity against anaerobic agents, we advise 4.5 to 5 mg/kg of gentamicin as a single dose as many studies support the safety and efficacy of this dose when used as a single dose for prophylaxis in patients without renal insufficiency. In addition, a trial of antibiotic prophylaxis in colorectal surgery reported that this dose may be more effective than multiple standard doses of 1.5 mg/kg during prolonged surgeries [77]. However, cesarean birth typically takes less than an hour; thus, a lower dose of gentamicin may be adequate; there are no comparative dosing trials in this population. Single daily dose gentamicin dosing does not appear be associated with more neonatal nephrotoxicity or auditory toxicity than multiple daily doses [78].

●For patients at low risk of a serious immediate allergic reaction, cefazolin can be administered, as described above (see 'Regimen' above). The risk of a penicillin-allergic patient reacting to a cephalosporin may be assessed based upon the results of penicillin skin testing (ideally performed prenatally), the clinical features of the penicillin reaction, and the time elapsed since the last reaction to penicillin (algorithm 1). If cesarean is performed intrapartum or after rupture of membranes, we add azithromycin 500 mg intravenously. (See "Allergy evaluation for immediate penicillin allergy: Skin test-based diagnostic strategies and cross-reactivity with other beta-lactam antibiotics" and "Penicillin allergy: Immediate reactions".)

Patients already on antibiotics — There are no randomized trials assessing efficacy of antibiotic regimens in these clinical scenarios.

●Patients receiving GBS prophylaxis – When cesarean birth is performed in a patient in labor or with ruptured membranes receiving penicillin G for neonatal Group B Streptococcus (GBS) prophylaxis, we do not add a cephalosporin or switch to ampicillin for surgical prophylaxis, but we add a 500 mg dose of azithromycin. Alternatively, some clinicians add a single dose of a narrow-spectrum antibiotic (eg, cefazolin) as well as a dose of azithromycin to the penicillin G protocol for GBS prophylaxis.

●Patients with chorioamnionitis – Ampicillin plus gentamicin is a common regimen for treatment of chorioamnionitis. For patients already on this regimen, we also administer either one dose of clindamycin 900 mg or metronidazole 500 mg before beginning the cesarean. We do not administer azithromycin to these patients.

Postpartum, it is reasonable to either continue ampicillin plus gentamicin or switch to ampicillin-sulbactam until the patient is afebrile for at least 24 hours. Bacteroides resistance to clindamycin is increasing, thus, in areas of high resistance, ampicillin-sulbactam is preferable. (See "Clinical chorioamnionitis", section on 'Postpartum care'.)

Prolonged surgery or excessive blood loss — Antibiotic levels fall over time and with blood loss. Although redosing is the standard of care in other surgeries, there are no specific data for cesarean birth [79]. A second dose of cefazolin is reasonable in patients with postpartum hemorrhage >1500 mL [58]. A second dose of cefazolin is also appropriate for the rare complicated cesarean birth that extends beyond four hours since the half-lives of cefazolin and azithromycin are approximately 1.8 and 68 hours, respectively.

A joint guideline of the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the Surgical Infection Society, and the Society for Healthcare Epidemiology of America suggests consideration of additional intraoperative doses in patients with excessive blood loss (>1500 mL) or extended surgery (duration exceeding two half-lives of the drug) [56,80].

Nasal colonization with methicillin-resistant S. aureus — Routine screening for MRSA is not indicated. Management of patients known to be colonized (eg, addition of a single dose of vancomycin) is discussed separately. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Role of vancomycin'.)

Thromboembolism prophylaxis

Risk of venous thromboembolism and pulmonary embolism — Pulmonary embolism is a common cause of maternal mortality [81] and over 80 percent of fatal puerperal pulmonary embolism occurs after cesarean birth [82]; however, the absolute level of risk for clinically important events is low and similar to that seen in very low-risk surgical patients, in whom routine thromboprophylaxis is not recommended (other than early ambulation). The incidence of postpartum thrombotic events is described separately. (See "Cesarean birth: Postoperative care, complications, and long-term sequelae", section on 'Venous thromboembolism'.)

Our approach — The value of thromboprophylaxis for cesarean birth has not been studied in adequately powered, randomized trials that have assessed and quantified both benefits (prevention of venous thrombosis and/or pulmonary embolism) and harms (wound or bleeding complications, including unplanned surgical procedures and blood transfusions) [83-85]. International guidelines for thromboprophylaxis after cesarean differ markedly in selection of patients for thromboprophylaxis because both the optimal threshold for initiating pharmacologic thromboprophylaxis and optimal duration of therapy are unclear [86]. Furthermore, no easy-to-use, validated tool is available for accurately determining absolute risk of postpartum VTE in an individual patient, although pilot studies of such tools have been published [87,88]. Clinical validation is difficult given the relatively low incidence of VTE.

This is our approach, which is generally consistent with ACOG recommendations [89]:

●Low-risk patients

•We place a pneumatic compression device on all patients before cesarean birth

•We encourage early ambulation after cesarean birth, as soon as eight hours postoperatively

We continue pneumatic compression until the patient is fully ambulatory [90]. Pneumatic compression devices may be removed while the patient is ambulating but should be put back on when they return to a seated or supine position. Observational studies of pregnant patients suggest that pneumatic compression devices, as well as graduated compression stockings, are safe and effective [91,92].

●High-risk patients

•We use both mechanical and pharmacologic thromboprophylaxis in patients at high risk of VTE undergoing cesarean birth

•We encourage early ambulation after cesarean birth, as soon as eight hours postoperatively

Criteria for selecting patients at high risk are challenging as high-quality data are not available [93]. We consider any of the following reasonable criteria for mechanical plus pharmacologic prophylaxis:

•Previous VTE.

•Any thrombophilia (inherited or acquired).

•Body mass index (BMI) >35 kg/m².

•≥2 less prominent risk factors for VTE – Numerous less prominent risk factors for VTE are described in the literature (eg, postpartum hemorrhage or infection, medical factors or pregnancy complications such as obesity, hypertension, autoimmune disease, heart disease, sickle cell disease, multiple gestation, preeclampsia); ACCP and RCOG risk factors are described below [94-105] (see 'ACCP recommendations' below and 'RCOG recommendations' below).

The type and number of less prominent risk factors that meet the threshold for administering pharmacologic prophylaxis is decided on a case-by-case basis.

●Timing of initiation of pharmacologic therapy – Pharmacologic prophylaxis is generally begun 6 to 12 hours after cesarean birth to minimize bleeding complications, unless there is significant bleeding or risk for significant bleeding [89].

The following timing considerations apply to patients who underwent a neuraxial procedure (see "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication"):

•The American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines [106]:

-Prophylactic dose low molecular weight heparin (LMWH) – Wait 6 to 12 hours after birth and no sooner than 4 hours after epidural catheter removal (whichever is later).

-Therapeutic dose LMWH – Wait 24 hours after birth, as long as hemostasis is ensured and epidural placement was not bloody or traumatic. Intravenous heparin can be used as a bridge if therapeutic anticoagulation is desired <24 hours after birth.  

•The Society for Obstetric Anesthesia and Perinatology Consensus Statement on the Anesthetic Management of Pregnant and Postpartum Women Receiving Thromboprophylaxis or Higher Dose Anticoagulants [107]:

-Prophylactic dose subcutaneous unfractionated heparin (UFH) – Wait ≥1 hour after a neuraxial block and ≥1 hour after epidural catheter removal.

-Prophylactic dose LMWH – Wait ≥12 hours after a neuraxial block and ≥4 hours after epidural catheter removal.

-Therapeutic dose LMWH – Consider waiting ≥24 hours after a neuraxial block and ≥4 hours after epidural catheter removal. In select circumstances, UFH can be used as a bridge because it can be restarted sooner than LMWH.

●Heparin dosing – UFH or LMWH (eg, enoxaparin) can be used. In the absence of an indication for therapeutic-dose anticoagulation (eg, higher-risk thrombophilia), we generally prefer a LWMH at a low dose given once a day based on evidence from a large trial that it is as effective as intermediate dosing in VTE prevention [108]. For example:

•Body weight <100 kg

-Enoxaparin 40 mg (4000 units) or dalteparin 5000 units subcutaneously once daily [108]

-Alternatively, if LMWH is unavailable or contraindicated, UFH 5000 units subcutaneously every 12 hours

•Body weight ≥100 kg

-Enoxaparin 60 mg (6000 units) or dalteparin 7500 units subcutaneously daily [108]

-Alternatively, if LMWH is unavailable or contraindicated, UFH 5000 units subcutaneously every eight hours

Patients who require prolonged anticoagulation can be switched to an oral agent (eg, warfarin [can be used during lactation] or a direct oral anticoagulant [should not be used during lactation]). (See "Use of anticoagulants during pregnancy and postpartum", section on 'Postpartum and breastfeeding'.)

●Duration of mechanical and pharmacologic prophylaxis – Pneumatic compression devices should be left in place until pharmacologic prophylaxis has been started. We generally continue the device until the patient is discharged as it may offer additive benefit to surgical patients on heparin. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

Pharmacologic prophylaxis is continued until the patient is fully ambulating, except for those with significant risk factors for postpartum VTE. Patients with a prior VTE should receive at least six weeks of thromboprophylaxis. Those with a VTE during the index pregnancy are treated for at least three months and this duration should include the remainder of pregnancy and at least six weeks postpartum. Those with a high risk thrombophilia may require an indefinite period of anticoagulation. (See "Use of anticoagulants during pregnancy and postpartum", section on 'Duration of postpartum anticoagulation' and "Selecting adult patients with lower extremity deep venous thrombosis and pulmonary embolism for indefinite anticoagulation" and "Antiphospholipid syndrome: Obstetric implications and management in pregnancy" and "Inherited thrombophilias in pregnancy" and "Venous thromboembolism in pregnancy and postpartum: Treatment".)

Recommendations of others

ACCP recommendations — This is a partial synopsis of 2012 ACCP guidelines for antithrombotic therapy and prevention of thrombosis in pregnancy [94]:

●For patients whose only risk factors for VTE are pregnancy and cesarean birth, the ACCP recommends only early ambulation postpartum.

●For patients undergoing cesarean birth with one additional major risk factor for VTE or at least two additional minor risk factors for VTE, the ACCP recommends pharmacologic thromboprophylaxis while in the hospital following birth. If anticoagulants are contraindicated, graduated compression stockings or a pneumatic compression device is recommended.

●For patients undergoing cesarean birth who are very high risk for VTE and have multiple additional risk factors for VTE that persist in the puerperium, the ACCP recommends pharmacologic thromboprophylaxis PLUS graduated compression stockings and/or pneumatic compression devices while in the hospital following birth.

●For selected high-risk patients in whom significant risk factors persist after giving birth, the ACCP suggests extended pharmacologic prophylaxis for up to 6 weeks following discharge from the hospital.

In 2016, several of the ACCP authors slightly revised the original risk factor criteria [109]. Their most recent guidance for prevention of VTE after cesarean birth states:

Prophylaxis should be provided after cesarean birth to patients with the following risk factors:

●One or more of: prior VTE, history of antepartum immobilization (strict bedrest for at least 1 week), significant postpartum infection, postpartum hemorrhage ≥1000 mL requiring reoperation, preeclampsia with growth restriction, significant medical co-morbidities (systemic lupus erythematosus, heart disease, or sickle cell disease), or a known thrombophilia.

●Two or more of (or one or more in the setting of emergency cesarean birth): postpartum hemorrhage ≥1000 mL not requiring reoperation, BMI >30 kg/m², fetal growth restriction, preeclampsia, multiple pregnancy, and tobacco use during pregnancy (≥10 cigarettes/day).

RCOG recommendations — The Royal College of Obstetricians and Gynaecologists (RCOG) stated that "all women who have had caesarean sections should be considered for thromboprophylaxis with LMWH for 10 days after delivery, apart from those having an elective caesarean section who should be considered for thromboprophylaxis with LMWH for 10 days after delivery if they have any additional risk factors. Thromboprophylaxis should be continued for six weeks in high-risk women and for 10 days in intermediate-risk women" [105].

The RCOG considers the following risk factors for VTE (refer to RCOG guideline for detailed description of risk assessment): previous VTE, thrombophilia, some medical comorbidities (eg, cancer; heart failure; active SLE, inflammatory polyarthropathy, or bowel disease; nephrotic syndrome; type I diabetes mellitus with nephropathy; sickle cell disease; current intravenous drug user), age >35 years, BMI ≥30 kg/m², parity ≥3, gross varicose veins (symptomatic or above knee or with associated phlebitis, edema/skin changes), paraplegia, multiple pregnancy, preeclampsia, preterm birth, postpartum hemorrhage >1 L/requiring transfusion, admission/immobility ≥3 days, current systemic infection [105].

However, RCOG criteria for thromboprophylaxis after cesarean birth would apply to half of United States cesarean birth patients (1.2 million a year), and the drugs alone could cost up to USD $52 million for a 4-day course and USD $130 million for a 10-day course [93].

Postpartum hemorrhage prophylaxis — An evidence-based tool should be used to determine maternal hemorrhage risk and, in turn, appropriate preparations for the specific individual's degree of risk. (See "Overview of postpartum hemorrhage", section on 'Institutional planning and preparation'.)

We often administer tranexamic acid before making the skin incision and then administer routine uterotonic drug prophylaxis (eg, oxytocin, carbetocin) after delivery of the anterior shoulder. This is an increasingly common approach for prophylaxis against postpartum hemorrhage, even in low-risk patients, and reviewed separately. (See "Management of the third stage of labor: Prophylactic pharmacotherapy to minimize hemorrhage".)

Prevention of nausea and vomiting — Nausea with or without vomiting occurs commonly during cesarean with neuraxial anesthesia. Prophylaxis for intraoperative and postoperative nausea and vomiting is routine. (See "Anesthesia for cesarean delivery", section on 'Preventing nausea and vomiting'.)

Other issues to consider

●Bowel preparation (oral and/or mechanical) is not beneficial and is not recommended [8,110].

●Surgery in patients with severe obesity presents additional challenges that are discussed separately. (See "Cesarean birth: Overview of issues for patients with obesity".)

FETOPLACENTAL ASSESSMENT

Fetal heart rate monitoring — For patients waiting to undergo a planned cesarean birth, the value of continuous or intermittent fetal heart rate monitoring following admission is unclear [111], no randomized trials examining this issue have been performed. At a minimum, the fetal heart rate should be documented upon admission, similar to other vital signs. If the patient has been undergoing antepartum fetal testing, it is reasonable to perform an admission nonstress test and discontinue monitoring if the tracing is reactive. If there is an excessive delay between anesthetic placement and abdominal preparation for surgery, it is appropriate to recheck the fetal heart rate during this interval.

For laboring patients, fetal heart rate monitoring should continue after transfer to the operating room, to the extent possible. External monitors are removed when the abdominal preparation is begun; internal monitors may be removed when the abdominal preparation is completed, although in some cases surgeons may elect to continue monitoring until birth, especially if the incision to delivery interval may be prolonged because of adhesions or other factors.

Fetal presentation and placental location — An ultrasound for assessment of placental location and fetal presentation (or abdominal examination to assess fetal presentation) may be useful before surgery, but is not routinely required. This information is helpful in selected patients. For example, it may help the surgeon avoid disturbing an anterior placenta or fibroid at hysterotomy and may help with plan the delivery of a fetus in nonvertex presentation.

INTRAOPERATIVE MATERNAL PREPARATION

Room temperature — Normothermia should be maintained during anesthesia and surgery. Patients receiving neuraxial anesthesia become hypothermic to a degree that is similar to those having general anesthesia. (See "Perioperative temperature management".)

Music — In patients undergoing a cesarean birth, music was associated with decreased intraoperative anxiety in a meta-analysis of randomized trials [112]. Therefore, we suggest asking patients their preference for having or not having music, and what kind of music they would like during the cesarean.

Supplemental oxygen — There is no benefit in maternal or perinatal clinical outcomes from routine administration of extra oxygen during cesarean birth [113].

Bladder catheterization — There is no high-quality evidence that routine placement of an indwelling catheter is advantageous [114,115]. As an alternative, patients at low risk of intraoperative complications can be asked to void shortly before entering the operating room. If subsequently required, an indwelling catheter can be inserted intraoperatively or postoperatively, and removed as soon as possible [116-119].

Nevertheless, many clinicians insert a urethral catheter at the start of the case to maintain bladder drainage and thereby improve visualization during surgery and minimize bladder injury. The catheter is also useful for instilling dye if a cystotomy is suspected and for monitoring urine output. Potential harms include an increased risk of urinary tract infection, urethral pain, voiding difficulties after removal of the catheter, delayed ambulation, and longer hospital stay [115]. If inserted, the catheter should be removed soon after the end of the cesarean [120].

Hair removal — Meta-analyses of randomized trials in nonpregnant patients report no difference in the rate of surgical site infection (SSI) in those who had hair removed prior to surgery versus those who did not [121,122]. No randomized trials assessing this intervention specifically before cesarean birth have been performed.

If hair needs to be removed, it should be clipped rather than shaved as patients who are shaved are more likely to develop SSI. Use of a depilatory cream is also preferable to shaving. Clipping should be performed just before surgery. (See "Overview of control measures for prevention of surgical site infection in adults", section on 'Hair removal'.)

Skin preparation — We prepare the abdominal surgical site with a chlorhexidine-alcohol scrub before cesarean birth based on data from three randomized trials that reported a reduction in SSI or positive bacterial wound cultures compared with iodine-alcohol skin preparation; two trials were in patients undergoing cesarean birth [123,124] and the other in adults undergoing clean-contaminated surgery [125].

However, use of iodine-alcohol, povidone-iodine, or chlorhexidine soap is also reasonable. Alcohol-based surgical prep solutions contain approximately 70 to 75 percent isopropyl alcohol and serve as fuels if not allowed to dry sufficiently before use of an ignition source; at least three minutes are required. Therefore, preparation with povidone-iodine or chlorhexidine soap (eg, Hibiclens) is advantageous when surgery cannot be delayed, as these solutions are not flammable.

A 2020 meta-analysis of randomized trials evaluating skin preparation techniques concluded there was insufficient evidence overall for determining the most effective skin preparation technique for preventing post-cesarean SSI or for reducing other undesirable outcomes [126]. Of note, in the subanalysis comparing chlorhexidine-alcohol versus povidone-iodine, chlorhexidine-alcohol was more effective in reducing SSI (risk ratio [RR] 0.72, 95% CI 0.58-0.91, eight trials, 4323 patients), but the difference was attenuated when four trials at high risk of bias were removed. The American College of Obstetricians and Gynecologists and the Enhanced Recovery After Surgery (ERAS) Society guideline for intraoperative care in cesarean birth recommend use of an alcohol-based mixed solution, such as chlorhexidine-alcohol [9,58].

Vaginal preparation — For patients in labor and patients with ruptured membranes, the author of this topic performs a 4% chlorhexidine gluconate vaginal scrub with a sponge stick for 30 seconds with three passes to lower SSI risk, particularly endometritis. Povidone-iodine is a reasonable alternative but was less effective in one of the largest randomized trials comparing these two options [127]. Importantly, preparations with a high alcohol content (chlorhexidine gluconate with 70% alcohol used for skin preparation) should be avoided in the vagina because alcohol irritates mucous membranes [58].

In a 2020 meta-analysis of randomized trials of vaginal cleansing (povidone-iodine or chlorhexidine) versus placebo/no intervention before cesarean birth, vaginal cleansing resulted in reductions in endometritis (3 versus 7.2 percent, RR 0.41, 95% CI 0.29-0.58), postoperative fever (RR 0.64, 95% CI 0.50-0.82), and wound infection (3.8 versus 6.1 percent, RR 0.62, 95% CI 0.50-0.77) [128]. Neither cleansing agent resulted in adverse effects. In subgroup analysis, the benefits were present whether iodine-based or chlorhexidine-based solutions were used and greatest in patients in labor or with ruptured membranes before the cesarean. However, a subsequent randomized trial specifically comparing precesarean abdominal plus vaginal cleansing (povidone-iodine) in patients in labor, with rupture of membranes, or with cervical dilation >4 cm found no significant difference in postoperative infectious morbidity compared with abdominal cleansing alone (11.8 versus 11.5 percent; RR 1.0, 95% CI 0.7-1.6) [129]. 

A network meta-analysis of randomized trials confirmed that all antiseptic formulations (povidone-iodine, chlorhexidine, metronidazole gel, cetrimide) decreased the rate of endometritis compared with placebo (5.2 versus 9.1 percent, odds ratio [OR] 0.48, 95% CI 0.35-0.65); povidone-iodine had the highest probability of reducing the risk of endometritis, postoperative wound infections, and fever [130]. In the only trial that compared wound infection rates in patients assigned to chlorhexidine versus povidone-iodine before cesarean birth, the rate was lower in the chlorhexidine arm (0.6 versus 2 percent, OR 0.28, 95% CI 0.08-0.98) [127], which is the basis for the author’s preference for chlorhexidine. Endometritis rates were low and similar in both arms (0.4 and 0.5 percent).

Nonadhesive drapes — The surgical site is draped with nonadhesive drapes as a meta-analysis of two randomized trials in patients undergoing cesarean birth found that nonadhesive drapes resulted in a statistically significant reduction in the rate of wound infection compared with adhesive drapes (10.7 versus 13.8 percent) [131].

Uterine displacement — The uterus is typically displaced at least 15 degrees to the left to reduce aortocaval compression (supine hypotensive syndrome), which can occur in the supine position when the uterus is at or above the umbilicus [132-136]. A foam or wood wedge, pillow, or rolled blanket may be used, or the table can be tilted, or the uterus can be manually displaced. A systematic review was not able to determine the optimum method or maternal position [137]. (See "Anesthesia for cesarean delivery", section on 'Intraoperative positioning'.)

Perioperative management of medication — Perioperative medication management is similar to that for other surgical procedures, and discussed separately. (See "Perioperative medication management".)

Hemodynamic management — Preoperative and intraoperative euvolemia are desirable to avoid maternal and fetal complications of hypotension or fluid overload. The anesthesia team aims to maintain blood pressure within 10 to 20 percent of baseline blood pressure unless the patient has severe hypertension. Crystalloid solutions are used more commonly than colloid solutions. Glucose-free solutions should be used to prevent neonatal hypoglycemia. Vasopressors may be administered prophylactically and as needed. (See "Anesthesia for cesarean delivery", section on 'Hemodynamic management'.)

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: Cesarean birth".)

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 5^th to 6^th 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 10^th to 12^th 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: Cesarean birth (The Basics)")

●Beyond the Basics topics (see "Patient education: C-section (cesarean delivery) (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Indications – Cesarean birth is performed when the clinician and patient believe that abdominal delivery is likely to provide a better maternal or fetal outcome than vaginal delivery. A wide variety of conditions fulfill these criteria. (See 'Indications' above.)

●Scheduling planned cesareans – Planned primary cesarean birth at term should be performed in the 39^th week of gestation rather than in the 37^th or 38^th week. Medically/obstetrically indicated cesarean births are performed when clinically indicated. (See 'Scheduling' above.)

Timing of planned repeat cesarean birth is based on the type of previous hysterotomy incision and is reviewed separately. (See "Repeat cesarean birth", section on 'Timing'.)

●Postpartum hemorrhage prophylaxis – An evidence-based tool should be used for determining maternal hemorrhage risk on admission to labor and delivery. Based on assessment of low, medium, or high risk of hemorrhage, blood is sent to the blood bank for holding in readiness, type and screen, or crossmatch, respectively. (See 'Laboratory testing' above and 'Postpartum hemorrhage prophylaxis' above.)

●Antibiotic prophylaxis

•Routine prophylaxis – For all patients undergoing cesarean birth, we recommend preoperative antibiotic prophylaxis rather than no prophylaxis or prophylaxis after cord clamping (Grade 1A).

-We administer a single intravenous dose of a narrow-spectrum antibiotic, such as cefazolin (2 grams for patients <120 kg and 3 grams for patients ≥120 kg) up to 60 minutes before making the incision.

-If the cesarean birth is performed intrapartum or after rupture of membranes, we add a single dose of azithromycin 500 mg intravenously. (See 'Regimen' above and 'Prolonged surgery or excessive blood loss' above.)

•Patients with penicillin allergy – For patients with a history of serious forms of penicillin allergy (algorithm 1), we substitute clindamycin and gentamicin for cefazolin. Patients at low risk of a serious immediate allergic reaction can receive cefazolin. If the cesarean birth is performed intrapartum or after rupture of membranes, we add a dose of azithromycin 500 mg intravenously. (See 'Patients with penicillin allergy' above.)

•For patients already receiving penicillin G for prophylaxis of neonatal Group B Streptococcus (GBS) infection, we do not add cefazolin or switch to ampicillin for surgical prophylaxis. If the cesarean birth is performed intrapartum or after rupture of membranes, we add a dose of azithromycin 500 mg intravenously. (See 'Patients already on antibiotics' above.)

•For patients receiving ampicillin and gentamicin for chorioamnionitis, we add either one dose of clindamycin 900 mg or metronidazole 500 mg before making the incision, and continue ampicillin and gentamicin or switch to ampicillin-sulbactam postpartum until the patient is afebrile for at least 24 hours. Bacteroides resistance to clindamycin is increasing; in areas of high resistance, ampicillin-sulbactam is preferable. We do not administer pre-incision prophylactic azithromycin in this setting. (See 'Patients already on antibiotics' above.)

●Skin preparation – We use a chlorhexidine-based antiseptic agent rather than an iodine-based antiseptic agent for skin preparation, but either approach is reasonable. Chlorhexidine-alcohol solutions should be allowed to dry for at least three minutes before using an ignition source, otherwise a nonflammable preparation (povidone-iodine or chlorhexidine soap) should be used. (See 'Skin preparation' above.)

●Vaginal preparation – For patients in labor and patients with ruptured membranes, we suggest vaginal cleansing before cesarean birth rather than no vaginal cleansing (Grade 2C). We use a 4% chlorhexidine gluconate vaginal scrub, but povidone-iodine is also reasonable. (See 'Vaginal preparation' above.)

●Thromboprophylaxis

•For all patients undergoing cesarean birth, we suggest mechanical thromboprophylaxis (Grade 2C).

•For patients undergoing cesarean birth at high risk of venous thromboembolism (VTE), we suggest mechanical thromboprophylaxis plus pharmacologic thromboprophylaxis (Grade 2C).

Low-dose pharmacologic prophylaxis is typically started 6 to 12 hours after surgery, in the absence of specific concerns about hemorrhage. Mechanical and pharmacologic prophylaxis are continued until the patient is fully ambulating, except for those with significant risk factors for postpartum VTE. Patients with a prior VTE receive at least six weeks of thromboprophylaxis. Those with a VTE during the index pregnancy are treated for at least three months and this duration should include the remainder of pregnancy and at least six weeks postpartum. Those with a high risk of thrombophilia may require an indefinite period of anticoagulation. (See 'Thromboembolism prophylaxis' above.)