What's new in obstetrics and gynecology

The following represent additions to UpToDate from the past six months that were considered by the editors and authors to be of particular interest. The most recent What's New entries are at the top of each subsection.

PRENATAL OBSTETRICS

Fetoplacental GDF15 linked to nausea and vomiting of pregnancy (February 2024)

Almost all pregnant people experience nausea with or without vomiting in early pregnancy; however, the pathogenesis of the disorder has been unclear. Previous studies have shown that GDF15 is expressed in a wide variety of cells, with the highest expression in placental trophoblast, and that its protein (GDF15) appears to regulate appetite. A recent study confirmed the fetoplacental unit as a major source of GDF15 and also found that higher GDF15 levels correlated with more severe nausea and vomiting of pregnancy [1]. In the future, drugs targeting the production or action of GDF15 are a potential novel pathway for treating nausea and vomiting of pregnancy, if safety and efficacy are established. (See "Nausea and vomiting of pregnancy: Clinical findings and evaluation", section on 'Pathogenesis'.)

Use of cerebroplacental ratio at term does not reduce perinatal mortality (February 2024)

Cerebral blood flow may increase in chronically hypoxemic fetuses to compensate for the decrease in available oxygen and can be assessed by the cerebroplacental ratio (CPR; middle cerebral artery pulsatility index divided by the umbilical artery pulsatility index). However, increasing evidence indicates that use of the CPR does not reduce perinatal mortality in low-risk pregnancies. In a randomized trial comparing fetal growth assessment plus revealed versus concealed CPR in over 11,000 low-risk pregnancies at term, knowledge of CPR combined with a recommendation for delivery if the CPR was <5th percentile did not reduce perinatal mortality compared with usual care (concealed group) [2]. We do not perform umbilical artery Doppler surveillance, including the CPR, in low-risk pregnancies. (See "Doppler ultrasound of the umbilical artery for fetal surveillance in singleton pregnancies", section on 'Low-risk and unselected pregnancies'.)

Low- versus high-dose calcium supplements and risk of preeclampsia (January 2024)

In populations with low baseline dietary calcium intake, the World Health Organization recommends 1500 to 2000 mg/day calcium supplementation for pregnant individuals to reduce their risk of developing preeclampsia. However, a recent randomized trial that evaluated low (500 mg) versus high (1500 mg) calcium supplementation in over 20,000 nulliparous pregnant people residing in two countries with low dietary calcium intake found low and similar rates of preeclampsia in both groups [3]. These findings suggest that a 500 mg supplement is sufficient to reduce the risk of preeclampsia in these populations. For pregnant adults in the United States, we prescribe 1000 mg/day calcium supplementation, which is the recommended daily allowance to support maternal calcium demands without bone resorption. (See "Preeclampsia: Prevention", section on 'Calcium supplementation'.)

Respectful maternity care (January 2024)

Respectful maternity care is variably defined but broadly involves both absence of disrespectful conduct and promotion of respectful conduct toward pregnant individuals. A systematic review found that validated tools to measure respectful maternity care were available, but the optimal tool was unclear and high quality studies were lacking on the effectiveness of respectful maternity care for improving any maternal or infant health outcome [4]. Respectful maternal care is a basic human right, but how to best implement and monitor it and assess outcomes requires further study. (See "Prenatal care: Initial assessment", section on 'Effectiveness'.)

Outcome of a multifaceted intervention in patients with a prior cesarean birth (January 2024)

Patients with a pregnancy after a previous cesarean birth must choose between a trial of labor (TOLAC) and a planned repeat cesarean. The optimal care of such patients is unclear. In a multicenter, cluster-randomized trial including over 20,000 patients with one prior cesarean birth, a multifaceted intervention (patient decision support, use of a calculator to assess chances of a vaginal birth after cesarean [VBAC], sonographic measurement of myometrial thickness, clinician training in best intrapartum practices during TOLAC) reduced perinatal and major maternal morbidity composite outcomes compared with usual care [5]. VBAC and uterine rupture rates were similar for both groups. Further study is needed to identify the most useful component(s) of the intervention for reducing morbidity. (See "Choosing the route of delivery after cesarean birth", section on 'Person-centered decision-making model'.)

Serial amnioinfusions for bilateral renal agenesis (January 2024)

Bilateral renal agenesis (BRA) is incompatible with extrauterine life because prolonged oligohydramnios results in pulmonary hypoplasia, leading to postnatal respiratory failure. A prospective study (RAFT) assessed use of serial amnioinfusions to treat 18 cases of BRA diagnosed at <26 weeks of gestation [6]. Of the 17 live births, 14 survived ≥14 days and had placement of dialysis access, but only 6 survived to hospital discharge. Of the 4 children alive at 9 to 24 months of age, 3 had experienced a stroke and none had undergone transplant. These findings show that serial amnioinfusions for BRA mitigates pulmonary hypoplasia and increases short-term survival and access to dialysis; however, long-term outcome remains poor with no survival to transplantation. Serial amnioinfusions remain investigational and should be offered only as institutional review board-approved research. (See "Renal agenesis: Prenatal diagnosis", section on 'Investigative role of therapeutic amnioinfusion'.)

Prenatal genetic testing for monogenic diabetes due to glucokinase deficiency (December 2023)

In pregnant individuals with monogenic diabetes due to glucokinase (GCK) deficiency, management depends on the fetal genotype. If the fetus inherits the maternal GCK variant, maternal hyperglycemia will not cause fetal hyperinsulinemia and excessive growth, and maternal hyperglycemia does not require treatment. However, if the fetus does not inherit the pathogenic variant, maternal insulin therapy is indicated to prevent excessive fetal growth. Fetal ultrasound has been used to predict fetal genotype but has limited diagnostic utility. In a cohort of 38 pregnant individuals with GCK deficiency, fetal genetic testing using cell-free DNA in maternal blood had higher sensitivity (100 versus 53 percent) and specificity (96 versus 61 percent) for prenatal diagnosis of GCK deficiency compared with ultrasound measurement of fetal abdominal circumference [7]. When available, noninvasive prenatal genotyping should be used to guide management of GCK deficiency during pregnancy. (See "Classification of diabetes mellitus and genetic diabetic syndromes", section on 'Glucokinase'.)

Early metformin treatment of gestational diabetes mellitus (November 2023)

Usual initial gestational diabetes mellitus (GDM) care (ie, medical nutritional therapy, exercise) may result in a few weeks of hyperglycemia before a need for pharmacotherapy is established. In a randomized trial evaluating whether initiating metformin at the time of GDM diagnosis regardless of glycemic control improves clinical outcomes compared with usual care, the metformin group had a lower rate of insulin initiation and favorable trends in mean fasting glucose, gestational weight gain, and excessive fetal growth, but more births <2500 grams [8]. Rates of preeclampsia, neonatal intensive care unit admission, and neonatal hypoglycemia were similar for both groups. Given these mixed results, we recommend not initiating metformin at the time of GDM diagnosis except in a research setting. (See "Gestational diabetes mellitus: Glucose management and maternal prognosis", section on 'Does early metformin initiation improve glycemic control and reduce need for insulin?'.)

Automated insulin delivery in pregnant patients with type 1 diabetes (October 2023)

Hybrid closed-loop insulin therapy is associated with improved glucose control in nonpregnant adults and in children, but little information is available in pregnant people. In the first randomized trial in this population, hybrid closed-loop insulin delivery beginning at 11 weeks gestation improved glycemic control compared with standard insulin therapy in 124 patients with type 1 diabetes, without increasing their risk of severe hypoglycemia [9]. The system allowed customization of glycemic targets appropriate to pregnancy, in contrast to other commercially available systems in the United States. Additional study is needed to confirm these findings, evaluate the effects on obstetric and neonatal outcomes, and identify optimal candidates. (See "Pregestational (preexisting) diabetes mellitus: Antenatal glycemic control", section on 'Continuous subcutaneous insulin infusion (insulin pump)'.)

Valacyclovir for prevention of congenital cytomegalovirus infection (October 2023)

Emerging evidence suggests that maternal administration of valacyclovir for primary cytomegalovirus (CMV) infection substantially reduces the risk of congenital CMV infection, especially if begun prior to 14 weeks of gestation and within 8 weeks of the maternal infection. In a 2023 individual patient data meta-analysis (one randomized trial, two observational studies), maternal valacyclovir administration upon diagnosis of periconception or first-trimester primary CMV infection was associated with a 66 percent reduction in congenital CMV (11 versus 25 percent) [10]. We suggest high-dose oral valacyclovir (8g per day) for patients with a primary CMV infection in early pregnancy after a comprehensive discussion of the potential benefits and risks (eg, 2 percent risk of reversible maternal kidney failure). (See "Cytomegalovirus infection in pregnancy", section on 'Antiviral medication'.)

Respiratory syncytial virus vaccination in pregnancy (April 2023, Modified October 2023)

Respiratory syncytial virus (RSV) is a major cause of morbidity and mortality in infants. In October 2023, the United States Centers for Disease Control and Prevention, along with guidelines from other expert groups, endorsed RSV vaccination of pregnant individuals to reduce severe RSV infections in their infants [11-14]. Nirsevimab, a monoclonal antibody that can be given to infants postnatally to reduce the risk of severe RSV, has also been recently approved and endorsed by expert guidance panels. In settings where nirsevimab is not available, we suggest vaccination of pregnant individuals between 32 0/6 and 36 6/7 weeks of gestation in September through January (in the northern hemisphere) with inactivated nonadjuvanted recombinant RSV vaccine (RSVPreF; Abrysvo). In settings where both maternal vaccination and nirsevimab are available, the optimal preventive strategy remains uncertain, and, in most cases, it will not be possible to use both. For such patients, both options should be discussed and shared decision-making undertaken. (See "Immunizations during pregnancy", section on 'Choosing the optimal strategy'.)

Revised criteria for pregnancy morbidity in antiphospholipid antibody syndrome (September 2023)

Obstetric antiphospholipid syndrome (APS) is sometimes used to describe patients with pregnancy morbidity, a positive test for antiphospholipid antibodies within three years of the pregnancy morbidity, and findings not attributable to another APS domain. The American College of Rheumatology and European Alliance of Associations for Rheumatology have recently updated the classification criteria for pregnancy morbidity in APS [15]. Changes included more explicit criteria for gestational age and placental insufficiency (table 1). (See "Antiphospholipid syndrome: Obstetric implications and management in pregnancy", section on 'Adverse pregnancy outcomes defining APS'.)

Respectful, equitable, supportive maternity care (August 2023)

Respectful, equitable, and supportive maternity care is a basic human right that is not always achieved. In a recent survey of mothers in the United States, 90 percent of respondents were satisfied with the care they received during pregnancy, but 20 percent overall reported mistreatment, including requests for help refused or not responded to, physical privacy violated, and verbal abuse [16]. Approximately 30 percent of all respondents and 40 percent of Black, Hispanic, and multiracial respondents reported discrimination during maternity care. Multiple organizations have developed strategies that encourage a culture of respectful, equitable, and supportive maternity care. These strategies can be useful to providers, patients, and health care systems. (See "Prenatal care: Second and third trimesters", section on 'Respectful, equitable, and supportive maternity care'.)

Pessary placement for short cervical length does not reduce preterm birth (July 2023)

Previous meta-analyses of randomized trials comparing use of a cervical pessary versus no pessary (with or without vaginal progesterone) for asymptomatic patients at high risk for preterm birth (PTB) have found that a pessary did not result in a statistically significant reduction in spontaneous PTB; however, the trials had many limitations. In a recent well-designed randomized trial of over 500 patients with cervical length <20 mm, placement of an Arabin pessary at 16 to 23 weeks of gestation also demonstrated no benefit over usual care; the rate of PTB or fetal death <37 weeks was nearly the same for both groups [17]. Strengths of this trial were inclusion of a very high-risk population, exclusion of patients with a history of PTB, and routine use of vaginal progesterone in both groups. These findings further support our practice of not using a pessary to reduce PTB in patients with a short cervix. (See "Cervical insufficiency", section on 'Pessary'.)

INTRAPARTUM AND POSTPARTUM OBSTETRICS

Intrauterine postpartum hemorrhage control devices for managing postpartum hemorrhage (February 2024)

Intrauterine balloon tamponade and vacuum-induced uterine compression are the most common devices used for intrauterine postpartum hemorrhage (PPH) control in patients with atony, but it is unclear which device is superior as few comparative studies have been performed. In a retrospective study including nearly 380 patients with PPH, quantitative blood loss after placement, rate of blood transfusion, and discharge hematocrit were similar for both devices [18]. Based on these and other data, in the setting of ongoing uterine bleeding, rapid use of one of these devices is likely to be more important than the choice of device when both devices are available. (See "Postpartum hemorrhage: Use of an intrauterine hemorrhage-control device", section on 'Choice of method'.)

Labor epidural analgesia and risk of emergency delivery (December 2023)

It is well established that contemporary neuraxial labor analgesia does not increase the overall risk of cesarean or instrument-assisted vaginal delivery. However, a new retrospective database study of over 600,000 deliveries in the Netherlands reported that epidural labor analgesia was associated with an increased risk of emergency delivery (cesarean or instrument-assisted vaginal) compared with alternative analgesia (13 versus 7 percent) [19]. Because of potential confounders and lack of detail on epidural and obstetric management, we consider these data insufficient to avoid neuraxial analgesia or change the practice of early labor epidural placement to reduce the potential need for general anesthesia in patients at high risk for cesarean delivery. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Effects on the progress and outcome of labor'.)

Delayed cord clamping in preterm births (December 2023)

Increasing evidence supports delaying cord clamping in preterm births. In an individual participant data meta-analysis of randomized trials of delayed versus immediate cord clamping at births <37 weeks (over 3200 infants), delaying cord clamping for >30 seconds reduced infant death before discharge (6 versus 8 percent) [20]. In a companion network meta-analysis evaluating the optimal duration of delay, a long delay (≥120 seconds) significantly reduced death before discharge compared with immediate clamping; reductions also occurred with delays of 15 to <120 seconds but were not statistically significant [21]. For preterm births that do not require resuscitation, we recommend delayed rather than immediate cord clamping. We delay cord clamping for at least 30 to 60 seconds as approximately 75 percent of blood available for placenta-to-fetus transfusion is transfused in the first minute after birth. (See "Labor and delivery: Management of the normal third stage after vaginal birth", section on 'Preterm infants'.)

Vacuum-induced intrauterine tamponade for postpartum hemorrhage (November 2023)

Intrauterine tamponade (with a balloon, packing, or vacuum) may be used to manage patients with postpartum hemorrhage (PPH) resulting from uterine atony that is not controlled by uterotonic medications and uterine massage. However, outcome data regarding vacuum-induced tamponade are limited. A study of data from a postmarketing registry of over 500 patients with PPH and isolated atony treated with vacuum-induced tamponade reported that the device controlled bleeding without treatment escalation or bleeding recurrence in 88 percent following cesarean birth and 96 percent following vaginal birth, typically within five minutes [22]. These data are consistent with previously published outcomes. Given its efficacy and ease of use, vacuum-induced tamponade is an important option for managing PPH in centers where this device is available. (See "Postpartum hemorrhage: Use of an intrauterine hemorrhage-control device", section on 'Vacuum-induced tamponade'.)

Risk of pregnancy-associated venous and arterial thrombosis in sickle cell disease (November 2023)

Sickle cell disease (SCD) and pregnancy both confer an increased risk of venous thromboembolism (VTE), but the magnitude of the risk is unclear. In a new administrative claims data study involving >6000 people with SCD and >17,000 age- and race-matched controls who were followed for one year postpartum, the risk of VTE was 11.3 percent in the patients with SCD, versus 1.2 percent in controls [23]. Arterial thromboembolism was also increased (5.2 percent, versus 0.6 percent in controls). This study emphasizes the value of postpartum VTE prophylaxis in people with SCD and the need for vigilance in evaluating suggestive symptoms. (See "Sickle cell disease: Obstetric considerations", section on 'Maternal risks'.)

Racial disparities in anemia during pregnancy (October 2023)

A new study has found that racial disparities in anemia during pregnancy persist and may be increasing. This analysis involved nearly four million births in the state of California from 2011 to 2020 [24]. Antepartum anemia was most common in Black individuals (22 percent), followed by Pacific Islanders (18 percent), Native American and Alaska Native peoples (14 percent), multiracial individuals (14 percent), Hispanic individuals (13 percent), Asian individuals (11 percent), and White individuals (10 percent). Antepartum anemia is associated with an increase in severe maternal morbidity. The reasons for disparities are multifactorial. (See "Anemia in pregnancy", section on 'Racial disparities'.)

Intrapartum magnesium sulfate before preterm birth and cerebral palsy (October 2023)

Magnesium sulfate is typically administered to pregnant women with impending preterm birth <32 weeks of gestation to decrease the incidence and severity of cerebral palsy in offspring. However, the recent MAGENTA trial comparing the effects of magnesium sulfate versus placebo administered before impending preterm birth between 30 and 34 weeks of gestation found that it did not prevent cerebral palsy among surviving infants [25]. These findings do not change our current practice because the trial used a single 4 g bolus of magnesium sulfate alone, whereas we also provide an ongoing 1 g/hour infusion until delivery and do not use the medication after 32 weeks; the trial was likely underpowered to find a significant difference. (See "Neuroprotective effects of in utero exposure to magnesium sulfate", section on 'Lower and upper gestational age'.)

Zuranolone for severe postpartum depression (August 2023)

For patients with severe postpartum depression who prioritize rapid improvement, we suggest initial therapy with brexanolone; however, the agent requires continuous intravenous infusion for 60 hours in an inpatient facility. Recently, the US Food and Drug Administration approved zuranolone for postpartum depression; clinical availability is anticipated by the end of 2023 [26,27]. Zuranolone is an oral agent that is administered over 14 days, has a similar mechanism of action to brexanolone, and can also result in rapid remission of symptoms. We expect that some patients will prefer zuranolone over the infusion required for brexanolone. (See "Severe postpartum unipolar major depression: Choosing treatment", section on 'Treatment that is approved but not yet available'.)

OFFICE GYNECOLOGY

Infertility and autism spectrum disorder (December 2023)

Patients with infertility often ask about the impact of the disorder and its treatment on risk of autism spectrum disorder (ASD) in offspring. In a large population-based cohort study comparing ASD risk among children whose parents had subfertility (an infertility consultation without treatment), infertility treatment, or neither (unassisted conception), children in the subfertility and infertility treatment groups had a small increased risk of ASD compared with unassisted conception but the absolute risk was low (2.5 to 2.7 per 1000 person-years versus 1.9 per 1000 person-years with unassisted conception) [28]. The increased risk was similar in the subfertile and infertility treatment groups, suggesting that infertility treatment was not a major risk factor. Obstetrical and neonatal factors (eg, preterm birth) appeared to mediate a sizeable proportion of the increased risk for ASD. (See "Assisted reproductive technology: Infant and child outcomes", section on 'Confounders'.)

Macular changes related to pentosan polysulfate sodium (November 2023)

Macular eye disease has been reported in patients who have taken pentosan polysulfate sodium (PPS), which is used for the treatment of interstitial cystitis. In a prospective cohort study of 26 eyes with PPS maculopathy and >3000 g cumulative PPS exposure, progression of macular changes continued 13 to 30 months after drug cessation [29]. Median visual acuity decreased slightly; most patients reported progression of symptoms, including difficulty in low-light environments and blurry vision. These results indicate that PPS maculopathy progresses despite drug discontinuation, underscoring the importance of regular screening for maculopathy in patients with current or prior PPS exposure. (See "Interstitial cystitis/bladder pain syndrome: Management", section on 'Pentosan polysulfate sodium as alternative'.)

Vaginal laser therapy not effective for genitourinary syndrome of menopause (November 2023)

Laser devices, including the fractional microablative CO₂ laser, have been marketed for treatment of patients with genitourinary syndrome of menopause (GSM), but data regarding their safety and efficacy are limited. In a randomized trial including nearly 50 postmenopausal patients with GSM, treatment with CO₂ laser did not improve symptom severity compared with sham therapy [30]. Change in vaginal histology, which is a common surrogate determinant of treatment success, was similar in both groups at six months postprocedure. In addition, histologic features associated with a hypoestrogenic state correlated poorly with the severity of vaginal symptoms. Although the trial had limitations, these findings are consistent with other data and support our practice of not using laser treatment for patients with GSM. (See "Genitourinary syndrome of menopause (vulvovaginal atrophy): Treatment", section on 'Laser or radiofrequency devices'.)

Use of vaginal estrogen in breast cancer patients taking aromatase inhibitors (October 2023)

Use of vaginal estrogen to manage symptoms of genitourinary syndrome of menopause (GSM) may be harmful in patients with breast cancer on aromatase inhibitors (AIs). In a claims-based analysis, vaginal estrogen therapy was associated with a higher rate of breast cancer recurrence in patients taking versus not taking an AI [31]. Time to recurrence in the AI group was approximately 140 days. While this study had many limitations, these data support our general practice of avoiding vaginal estrogen for the management of GSM in most patients with breast cancer taking AIs. (See "Genitourinary syndrome of menopause (vulvovaginal atrophy): Treatment", section on 'Patients with breast cancer'.)

Fezolinetant, a neurokinin 3 receptor antagonist for hot flashes (August 2023)

Hormone therapy remains the most effective treatment for hot flashes. However, a new class of nonhormonal drugs, neurokinin 3 receptor (NK3R) antagonists, appears to be a reasonable alternative for those who cannot take hormone therapy. The first NK3R antagonist to be approved and available for clinical use is fezolinetant. In one trial of over 500 postmenopausal women with moderate-to-severe hot flashes, fezolinetant significantly reduced hot flash frequency and severity when compared with placebo [32,33]. After 12 weeks of therapy, the mean reductions in hot flash frequency for fezolinetant 45 mg, 30 mg, or placebo were 64, 59, and 45 percent, respectively. Women receiving fezolinetant 45 mg also had significant improvements in sleep disturbances when compared with placebo. (See "Menopausal hot flashes", section on 'Neurokinin 3 receptor antagonist'.)

Nonhormonal therapies for menopausal hot flashes (August 2023)

The 2023 nonhormonal therapy position statement from the Menopause Society suggests a number of treatment options for hot flashes in women who cannot take hormone therapy [34]. These include cognitive behavioral therapy, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, oxybutynin, gabapentin, and fezolinetant. Nonhormonal therapies that NAMS does not recommend for vasomotor symptoms include paced respiration, supplements/herbal remedies, cooling techniques, avoiding triggers, exercise, yoga, mindfulness-based intervention, relaxation, soy, cannabinoids, acupuncture, and clonidine. (See "Menopausal hot flashes", section on 'NAMS 2023 recommendations'.)

Mifepristone for treatment of adenomyosis (August 2023)

Symptomatic uterine adenomyosis is typically treated with nonsteroidal anti-inflammatory drugs, the 52 mg levonorgestrel-releasing intrauterine device, or surgery, but use of other hormonal medications (eg, oral contraceptive pills, gonadotropin-releasing hormone analogs, mifepristone) has been described. In a randomized trial including over 130 premenopausal patients with adenomyosis based on imaging, mifepristone (10 mg orally daily) resulted in greater improvement in dysmenorrhea, blood loss, and uterine volume compared with placebo after 12 weeks of treatment [35]. Further studies are needed to determine the long-term efficacy of mifepristone in such patients before it can be used routinely for this indication. (See "Uterine adenomyosis", section on 'Alternative hormone strategies'.)

GYNECOLOGIC SURGERY

Risk of subsequent hysterectomy after endometrial ablation (January 2024)

Endometrial ablation is an alternative to hysterectomy in selected premenopausal patients with heavy menstrual bleeding. Most ablations are performed using a non-resectoscopic technique; however, the long-term efficacy of this approach is unclear. In a meta-analysis of 53 studies including over 48,000 patients managed with non-resectoscopic endometrial ablation (NREA), the rates of subsequent hysterectomy were 4 percent at 12 months, 8 to 12 percent at 18 to 60 months, and 21 percent at 120 months [36]. Hysterectomy rates were similar for the different NREA devices (eg, thermal balloon, microwave, radiofrequency). These findings are useful for counseling patients about the long-term risk for hysterectomy after NREA. (See "Endometrial ablation: Non-resectoscopic techniques", section on 'Efficacy'.)

Pregnancy and childbirth after urinary incontinence surgery (January 2024)

Patients with stress urinary incontinence (SUI) have historically been advised to delay midurethral sling (MUS) surgery until after childbearing because of concerns for worsening SUI symptoms following delivery. In a meta-analysis of patients with MUS surgery who were followed for a mean of nearly 10 years, similar low SUI recurrence and reoperation rates were reported for the 381 patients with and the 860 patients without subsequent childbirth [37]. Birth route did not affect the findings. Although the total number of recurrences and reoperations was small, this study adds to the body of evidence suggesting that subsequent childbirth does not worsen SUI outcomes for patients who have undergone MUS. (See "Surgical management of stress urinary incontinence in females: Retropubic midurethral slings", section on 'Subsequent pregnancy'.)