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We aimed to evaluate whether delivering during the early the coronavirus disease 2019 (COVID-19) pandemic was associated with increased risk of maternal death or serious morbidity from common obstetric complications compared with a historical control period.This was a multicenter retrospective cohort study with manual medical-record abstraction performed by centrally trained and certified research personnel at 17 U.S. hospitals. Individuals who gave birth on randomly selected dates in 2019 (before the pandemic) and 2020 (during the pandemic) were compared. Hospital, health care system, and community risk-mitigation strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in response to the early COVID-19 pandemic are described. The primary outcome was a composite of maternal death or serious morbidity from common obstetric complications, including hypertensive disorders of pregnancy (eclampsia, end organ dysfunction, or need for acute antihypertensive therapy), postpartum hemorrhage (operative intervention or receipt of 4 or more units blood products), and infections other than SARS-CoV-2 (sepsis, pelvic abscess, prolonged intravenous antibiotics, bacteremia, deep surgical site infection). The major secondary outcome was cesarean birth.Overall, 12,133 patients giving birth during and 9,709 before the pandemic were included. Hospital, health care system, and community SARS-CoV-2 mitigation strategies were employed at all sites for a portion of 2020, with a peak in modifications from March to June 2020. Of patients delivering during the pandemic, 3% had a positive SARS-CoV-2 test result during pregnancy through 42 days postpartum. Giving birth during the pandemic was not associated with a change in the frequency of the primary composite outcome (9.3% vs 8.9%, adjusted relative risk [aRR] 1.02, 95% CI 0.93-1.11) or cesarean birth (32.4% vs 31.3%, aRR 1.02, 95% CI 0.97-1.07). No maternal deaths were observed.Despite substantial hospital, health care, and community modifications, giving birth during the early COVID-19 pandemic was not associated with higher rates of serious maternal morbidity from common obstetric complications.ClinicalTrials.gov, NCT04519502.

Pregnant patients with severe or critical coronavirus disease 2019 (COVID-19), but not those with mild or moderate COVID-19, were at increased risk for perinatal complications compared with asymptomatic patients., OBJECTIVE: To describe coronavirus disease 2019 (COVID-19) severity in pregnant patients and evaluate the association between disease severity and perinatal outcomes. METHODS: We conducted an observational cohort study of all pregnant patients with a singleton gestation and a positive test result for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who delivered at 1 of 33 U.S. hospitals in 14 states from March 1 to July 31, 2020. Disease severity was classified by National Institutes of Health criteria. Maternal, fetal, and neonatal outcomes were abstracted by centrally trained and certified perinatal research staff. We evaluated trends in maternal characteristics and outcomes across COVID-19 severity classes and associations between severity and outcomes by multivariable modeling. RESULTS: A total of 1,219 patients were included: 47% asymptomatic, 27% mild, 14% moderate, 8% severe, 4% critical. Overall, 53% were Hispanic; there was no trend in race–ethnicity distribution by disease severity. Those with more severe illness had older mean age, higher median body mass index, and pre-existing medical comorbidities. Four maternal deaths (0.3%) were attributed to COVID-19. Frequency of perinatal death or a positive neonatal SARS-CoV-2 test result did not differ by severity. Adverse perinatal outcomes were more frequent among patients with more severe illness, including 6% (95% CI 2–11%) incidence of venous thromboembolism among those with severe–critical illness compared with 0.2% in mild–moderate and 0% in asymptomatic (P

Our objective was to evaluate whether cannabis use was associated with nausea and vomiting in early pregnancy. Participants from nuMoM2b (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be) enrolled from October 2010 through September 2013 with a PUQE (Pregnancy-Unique Quantification of Emesis) questionnaire and an available stored urine sample from the first study visit (median gestational age 12 weeks) were included. Cannabis exposure was ascertained by urine immunoassay for 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH); positive results were confirmed with liquid chromatography tandem mass spectrometry. The primary outcome was moderate-to-severe nausea by the PUQE score. Overall, 9,250 participants were included, and 5.8% (95% CI 5.4-6.3%) had detectable urine THC-COOH. In adjusted analyses, higher THC-COOH levels were associated with greater odds of moderate-to-severe nausea (20.7% in the group with THC-COOH detected vs 15.5% in the group with THC-COOH not detected, adjusted odds ratio 1.6, 95% CI 1.1-2.2 for a 500 ng/mg Cr THC-COOH increment).

To compare health care medical resource utilization in low-risk nulliparous pregnancies according to body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) categories.This is a secondary analysis of a multicenter randomized controlled trial of induction of labor between 39 0/7 39 and 4/7 weeks of gestation compared with expectant management in low-risk nulliparous pregnant people, defined as those without standard obstetric indications for delivery at 39 weeks. Body mass index at randomization was categorized into four groups (lower than 25, 25-29, 30-39, and 40 or higher). The primary outcome of this analysis was time spent in the labor and delivery department from admission to delivery. Secondary outcomes included length of stay (LOS) postdelivery, total hospital LOS, and antepartum, intrapartum, and postpartum resource utilization, which were defined a priori. Multivariable generalized linear modeling and logistic regressions were performed, and 99% CIs were calculated.A total of 6,058 pregnant people were included in the analysis; 640 (10.6%) had BMIs of lower than 25, 2,222 (36.7%) had BMIs between 25 and 29, 2,577 (42.5%) had BMIs of 30-39, and 619 (10.2%) had BMIs of 40 or higher. Time spent in the labor and delivery department increased from 15.1±9.2 hours for people with BMIs of lower than 25 to 23.5±13.6 hours for people with BMIs of 40 or higher, and every 5-unit increase in BMI was associated with an average 9.8% increase in time spent in the labor and delivery department (adjusted estimate per 5-unit increase in BMI 1.10, 99% CI 1.08-1.11). Increasing BMI was not associated with an increase in antepartum resource utilization, except for blood tests and urinalysis. However, increasing BMI was associated with higher odds of intrapartum resource utilization, longer total hospital LOS, and postpartum resource utilization. For example, every 5-unit increase in BMI was associated with an increase of 26.1% in the odds of antibiotic administration, 57.6% in placement of intrauterine pressure catheter, 5.1% in total inpatient LOS, 31.0 in postpartum emergency department visit, and 23.9% in postpartum hospital admission.Among low-risk nulliparous people, higher BMI was associated with longer time from admission to delivery, total hospital LOS, and more frequent utilization of intrapartum and postpartum resources.ClinicalTrials.gov, NCT01990612.

To develop and internally validate a noninvasive method for the prediction of congenital cytomegalovirus (CMV) infection after primary maternal CMV infection.We conducted a secondary analysis of a multicenter randomized placebo-controlled trial of CMV hyperimmune globulin to prevent congenital infection. Women were eligible if they had primary CMV infection, defined as detectable plasma CMV-specific immunoglobulin (Ig)M and CMV-specific IgG with avidity less than 50% before 24 weeks of gestation or IgG seroconversion before 28 weeks, and were carrying a singleton fetus without ultrasonographic findings suggestive of CMV infection. Antibody assays were performed in a single reference laboratory. Congenital infection was defined as CMV detection in amniotic fluid, neonatal urine or saliva, or postmortem tissue. Using backward elimination, we developed logit models for prediction of congenital infection using factors known at randomization. The performance of the model was assessed using leave-one-out cross-validation (a method of internal validation).Of 399 women enrolled in the trial, 344 (86%) had informative data for this analysis. Congenital infection occurred in 68 pregnancies (20%). The best performing model included government-assisted insurance, IgM index 4.5 or higher, IgG avidity less than 32%, and whether CMV was detectable by polymerase chain reaction in maternal plasma at the time of randomization. Cross-validation showed an average area under the curve of 0.76 (95% CI 0.70-0.82), indicating moderate discriminatory ability. More parsimonious one-, two-, and three-factor models performed significantly less well than the four-factor model. Examples of prediction with the four-factor model: for a woman with government-assisted insurance, avidity less than 32%, IgM index 4.5 or higher, and detectable plasma CMV, probability of congenital infection was 0.69 (95% CI 0.53-0.82); for a woman with private insurance, avidity 32% or greater, IgM index less than 4.5, and undetectable plasma CMV, probability of infection was 0.03 (95% CI 0.02-0.07).We developed models to predict congenital CMV infection in the presence of primary maternal CMV infection and absence of ultrasonographic findings suggestive of congenital infection. These models may be useful for patient counseling and decision making.

Preterm birth is among the most complex and important challenges in obstetrics. Despite decades of research and clinical advancement, approximately 1 in 10 newborns in the United States is born prematurely. These newborns account for approximately three-quarters of perinatal mortality and more than one half of long-term neonatal morbidity, at significant social and economic cost (1-3). Because preterm birth is the common endpoint for multiple pathophysiologic processes, detailed classification schemes for preterm birth phenotype and etiology have been proposed (4, 5). In general, approximately one half of preterm births follow spontaneous preterm labor, about a quarter follow preterm prelabor rupture of membranes (PPROM), and the remaining quarter of preterm births are intentional, medically indicated by maternal or fetal complications. There are pronounced racial disparities in the preterm birth rate in the United States. The purpose of this document is to describe the risk factors, screening methods, and treatments for preventing spontaneous preterm birth, and to review the evidence supporting their roles in clinical practice. This Practice Bulletin has been updated to include information on increasing rates of preterm birth in the United States, disparities in preterm birth rates, and approaches to screening and prevention strategies for patients at risk for spontaneous preterm birth.

OBJECTIVE To evaluate differences in short-term perinatal outcomes between the two prominent screening strategies for gestational diabetes mellitus, the International Association of Diabetes and Pregnancy Study Groups (IADPSG) and Carpenter-Coustan. METHODS In this single-site, blinded, randomized, comparative effectiveness trial, participants received a nonfasting 50-g oral glucose tolerance test and, if less than 200 mg/dL (less than 11.1 mmol/L), were randomized to further screening with either IADPSG or Carpenter-Coustan criteria. Gestational diabetes treatment occurred per routine clinical care. The primary outcome was incidence of large-for-gestational-age (LGA) neonates. Prespecified secondary outcomes included small-for-gestational-age (SGA) neonates, cesarean birth, and neonatal and maternal composites of adverse perinatal outcomes. Assuming a 15% incidence of LGA neonates in the Carpenter-Coustan group, 782 participants provided more than 80% power to detect a 7% absolute risk reduction with the use of IADPSG; planned recruitment was 920 for anticipated attrition. RESULTS From June 2015 to February 2019, 1,016 participants were enrolled and 921 were randomized to IADPSG (n=461) or Carpenter-Coustan (n=460) groups. Gestational diabetes incidence (14.4% vs 4.5%, P

Intrauterine vacuum-induced hemorrhage control may provide an effective treatment option for postpartum hemorrhage that has the potential to prevent severe maternal morbidity and mortality., OBJECTIVE: To evaluate the effectiveness and safety of an intrauterine vacuum-induced hemorrhage-control device for postpartum hemorrhage treatment. METHODS: A multicenter, prospective, single-arm treatment study of a novel intrauterine device that uses low-level vacuum to induce uterine myometrial contraction to achieve control of abnormal postpartum uterine bleeding and postpartum hemorrhage was undertaken at 12 centers in the United States. The primary effectiveness endpoint was the proportion of participants in whom use of the intrauterine vacuum-induced hemorrhage-control device controlled abnormal bleeding without requiring escalating interventions. The primary safety endpoint was the incidence, severity, and seriousness of device-related adverse events. Secondary outcomes included time to bleeding control, rate of transfusion, and device usability scored by each investigator using the device. RESULTS: Of 107 participants enrolled with primary postpartum hemorrhage or abnormal postpartum uterine bleeding, 106 received any study treatment with the device connected to vacuum, and successful treatment was observed in 94% (100/106, 95% CI 88–98%) of these participants. In those 100 participants, definitive control of abnormal bleeding was reported in a median of 3 minutes (interquartile range 2.0–5.0) after connection to vacuum. Eight adverse events deemed possibly related to the device or procedure were reported, all of which were outlined as risks in the study and all of which resolved with treatment without serious clinical sequelae. Transfusion of 1–3 units of red blood cells was required in 35 participants, and five participants required 4 or more units of red blood cells. The majority of investigators reported the intrauterine vacuum-induced hemorrhage-control device as easy to use (98%) and would recommend it (97%). CONCLUSION: Intrauterine vacuum-induced hemorrhage control may provide a new rapid and effective treatment option for abnormal postpartum uterine bleeding or postpartum hemorrhage, with the potential to prevent severe maternal morbidity and mortality. FUNDING SOURCE: Alydia Health, Inc. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02883673.

OBJECTIVE To estimate whether maternal sense of control in labor is associated with breastfeeding at 4-8 weeks postpartum. METHODS This is a secondary analysis of data from a multicenter randomized controlled trial of elective induction of labor at 39 weeks of gestation in low-risk nulliparous women. In this trial, women completed the Labor Agentry Scale, a validated measure of women's feelings of control over the childbirth process, 6-96 hours after delivery. The Labor Agentry Scale score, which is higher with more perceived control during childbirth, was analyzed both as a continuous and a categorical variable (quintiles). Self-reported breastfeeding at 4-8 weeks postpartum was categorized as exclusive breastfeeding, breastfeeding and formula feeding, or exclusive formula feeding. Women were included in this analysis if they labored, filled out a Labor Agentry Scale questionnaire, had a neonate who survived until the postpartum visit, and provided information on infant feeding. Multinomial logistic regression was used to adjust for confounders. RESULTS Of 5,185 women, 32.9% (n=1,705) were exclusively breastfeeding, 31.2% (n=1,620) were breastfeeding and formula feeding, and 35.9% (n=1,860) were exclusively formula feeding 4-8 weeks after delivery. Overall Labor Agentry Scale score ranged from 34 to 203 (median 167, interquartile range 145-182). The median Labor Agentry Scale score was 169 (interquartile range 151-183) for women exclusively breastfeeding, 166 (interquartile range 142-182) for women who were breastfeeding and formula feeding, and 164 (interquartile range 142-181) for women who were only formula feeding (P

Objective To evaluate the relationship between acculturation and adverse pregnancy outcomes, and whether these relationships differ across racial or ethnic groups. Methods This is a planned secondary analysis of the nuMoM2b study (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be), a prospective observational cohort study of 10,038 pregnant women at eight academic health care centers in the United States. Nulliparous pregnant women with singleton gestations were recruited between 6 0/7 and 13 6/7 weeks of gestation from October 2010-September 2013. Acculturation was defined by birthplace (United States vs non-United States), language used during study visits (English or Spanish), and self-rated English proficiency. The adverse pregnancy outcomes of interest were preterm birth (less than 37 weeks of gestation, both iatrogenic and spontaneous), preeclampsia or eclampsia, gestational hypertension, gestational diabetes, stillbirth, small for gestational age, and large for gestational age. Multivariable regression modeling was performed, as was an interaction analysis focusing on the relationship between acculturation and adverse pregnancy outcomes by maternal race or ethnicity. Results Of the 10,006 women eligible for this analysis, 8,100 (80.9%) were classified as more acculturated (eg, born in the United States with high English proficiency), and 1,906 (19.1%) were classified as having less acculturation (eg, born or not born in the United States with low proficiency in English or use of Spanish as the preferred language during study visits). In multivariable logistic regression modeling, more acculturation was significantly associated with higher frequency of preterm birth (odds ratio [OR] 1.46, adjusted odds ratio [aOR] 1.50, 95% CI 1.16-1.95); spontaneous preterm birth (OR 1.54, aOR 1.62, 95% CI 1.14-2.24); preeclampsia or eclampsia (OR 1.39, aOR 1.31, 95% CI 1.03-1.67); preeclampsia without severe features (OR 1.44, aOR 1.43, 95% CI 1.03-2.01); and gestational hypertension (OR 1.68, aOR 1.48, 95% CI 1.22-1.79). These associations did not differ by self-described race or ethnicity. Conclusion In a large cohort of nulliparous women, more acculturation, regardless of self-described race or ethnicity, was associated with increased odds of several adverse pregnancy outcomes. Clinical trial registration ClinicalTrials.gov, NCT01322529.

To examine the relationship between prospectively assessed maternal sleep position and subsequent adverse pregnancy outcomes.This was a secondary analysis of a prospective observational multicenter cohort study of nulliparous women with singleton gestations who were enrolled between October 2010 and May 2014. Participants had three study visits that were not part of clinical care. They prospectively completed in-depth sleep questionnaires between 6 0/7 and 13 6/7 weeks of gestation and 22 0/7 and 29 6/7 weeks of gestation, the first and third study visits. A subset of women also underwent level 3 home sleep tests using the Embletta Gold device. The primary outcome was a composite of adverse pregnancy outcomes such as stillbirth, a small-for-gestational-age newborn, and gestational hypertensive disorders.A total of 8,706 (of 10,038) women had data from at least one sleep questionnaire and for pregnancy outcomes, and they comprised the population for this analysis. The primary outcome occurred in 1,903 pregnancies (22%). There was no association between reported non-left lateral or supine sleep during the last week of the first visit (adjusted odds ratio [aOR] 1.00 [95% CI 0.89-1.14]) or third visit (aOR 0.99 [95% CI 0.89-1.11] and the composite or any individual outcome, except for an apparent protective effect for stillbirth at the third visit (aOR 0.27 (95% CI 0.09-0.75). Women with objectively measured supine sleep position for at least 50% of the time were no more likely than those in the supine position 50% or less of the time to have the composite adverse outcome.Going to sleep in the supine or right lateral position, as self-reported before the development of pregnancy outcome and objectively assessed through 30 weeks of gestation, was not associated with an increased risk of stillbirth, a small-for-gestational-age newborn, or gestational hypertensive disorders.

Preterm birth is the leading cause of neonatal mortality and the most common reason for antenatal hospitalization . In the United States, approximately 12% of all live births occur before term, and preterm labor preceded approximately 50% of these preterm births . Although the causes of preterm labor are not well understood, the burden of preterm births is clear-preterm births account for approximately 70% of neonatal deaths and 36% of infant deaths as well as 25-50% of cases of long-term neurologic impairment in children . A 2006 report from the Institute of Medicine estimated the annual cost of preterm birth in the United States to be $26.2 billion or more than $51,000 per premature infant . However, identifying women who will give birth preterm is an inexact process. The purpose of this document is to present the various methods proposed to manage preterm labor and to review the evidence for the roles of these methods in clinical practice. Identification and management of risk factors for preterm labor are not addressed in this document.

To understand the relationship between cervical length and the risk of prematurity in parous women without a history of preterm delivery.Data from 2,998 singleton pregnancies enrolled in a multicenter, observational cohort study were analyzed. We subgrouped the population into the following categories: those with history of at least one spontaneous preterm birth (n=467); nulliparous (n=1,237); and parous with a history of at least one term birth and no previous preterm birth (low-risk history group, n=1,284). The relationship between cervical length (measured between 22 and 24 6/7 weeks of gestation) and preterm birth was examined using logistic regression [corrected].Assuming a 40% risk reduction with the use of vaginal progesterone, we calculated the number needed to screen to prevent one preterm birth.An inverse relationship between cervical length and risk of preterm birth was demonstrated for each subgroup. A short cervix (15 mm or less) was identified in only 0.93% of the low-risk group participants compared with 3.4% of the previous preterm birth group participants and 2.1% of nulliparous women. The overall rate of preterm birth was lowest (10.5%) in the low-risk history group; however, the rate of preterm birth for these women with a short cervix was 25%. For a cervical length cutoff of 15 mm or less, preventing one spontaneous delivery before 34 weeks of gestation would require screening 167 (95% confidence interval [CI] 112-317) women with a previous preterm birth, 344 (95% CI 249-555) nulliparous women, and 1,075 (95% CI 667-2,500) women at low risk.Although ultrasonographic short cervix is a risk factor for preterm birth among parous women with exclusively term births, the incidence of a short cervix is very low. The number needed to screen to prevent one preterm birth is considerably greater for women who have a low-risk obstetric history.: II.

To estimate and compare the risk of morbid perinatal outcomes in pregnancies identified as small for gestational age (SGA) with customized compared with conventional standards of fetal growth.Ultrasound-derived estimates of fetal weight were used to generate a fetal growth trajectory (N=7,510). The gestational age at delivery and pathologic and physiologic variables from 5,072 pregnancies were used to calculate a customized threshold for SGA. In a separate analysis of 32,070 pregnancies, rates of morbid outcomes were compared in participants classified as SGA according to a population-based birth weight standard only (SGApop only), a customized standard only (SGAcust only), and both methods (SGAboth).Eight-hundred seventy-five (2.7%) participants were SGApop only, 1,970 (6.1%) participants were SGAboth, and 609 (1.9%) participants were SGAcust only. The odds ratios of neonatal death in SGApop only and SGAcust only pregnancies were 1.78 (95% confidence interval [CI] 0.2-13.1) and 54.6 (95% CI 29.0-102.8), respectively. Rates of prematurity in the SGApop only and SGAcust only cohorts were 4.8% and 64.5%, respectively. After adjustment for the effect of prematurity, odds ratios of neonatal death in the SGApop only and SGAcust only cohorts were 4.8 (95% CI 0.6-37.0) and 2.9 (95% CI 1.4-6.1), respectively.After adjustment for confounding stemming from premature delivery, there is little difference in the risk of adverse outcomes between SGAcust only and SGApop only participants. Adoption of customized fetal growth standards into clinical practice may not improve the ability to identify pregnancies with increased risk of perinatal morbidity.

To estimate the rate of vaginal birth after cesarean delivery (VBAC) success in diabetic women based on White's Classification.This is a secondary analysis of an observational study conducted at 19 medical centers of women attempting VBAC. Diabetic women with singleton gestations, one prior cesarean delivery, and cephalic presentation who underwent a trial of labor were included. Vaginal birth after cesarean delivery success rates and maternal and neonatal complications were compared based on White's Classification.Of 11,856 women who underwent trial of labor, 624 met all study criteria (class A1, 356; A2, 169; B, 70; C, 21; D/R/F, 8). Vaginal birth after cesarean delivery success in each group was: A1, 68.5% (95% confidence interval [CI] 63.4-73.3%); A2, 55% (95% CI 47.2-62.7%); B, 70% (95% CI 57.9-80.4%); C, 47.6% (95% CI 25.7-70.2%); and D/F/R, 12.5% (95% CI 0.3-52.7%). Maternal and neonatal complications were rare and not found to be different among groups.Our study provides estimates for VBAC success based on White's classification and indicates a relatively low rate of perinatal complications after VBAC attempt for diabetic women.III.

To evaluate the association of early pregnancy concentrations of thrombin-antithrombin III complex with subsequent spontaneous preterm birth.In a nested case-control study, thrombin-antithrombin III complex was measured in plasma before 20 weeks of gestation (mean 9.9 weeks) among women without chronic conditions, preeclampsia, or growth restriction. C-reactive protein and non-high-density lipoprotein cholesterol were also measured. Women with spontaneous preterm birth before 34 weeks of gestation (n=29) and 34 weeks to 36 weeks of gestation (n=72) were compared with women with term births occurring at or after 37 weeks (n=219). Polychotomous logistic regression was used to relate elevated thrombin-antithrombin III complex (greater than 5.5 ng/mL), dyslipidemia (non-high-density lipoprotein cholesterol greater than the 90th percentile), and inflammation (C-reactive protein at or above 8 micrograms/mL) to risk of spontaneous preterm birth subtypes.Women with spontaneous preterm birth compared with term births had elevated thrombin-antithrombin III complex (P=.02), and they were more likely to have a thrombin-antithrombin III complex greater than 5.5 ng/mL (P.01). Women with thrombin-antithrombin III complex in the highest compared with lowest quartile had a 4.6-fold (95% confidence interval 1.3-15.8) increased risk for spontaneous preterm birth before 34 weeks of gestation, adjusted for body mass index, race, inflammation, dyslipidemia, and gestational age at sampling. There was a dose-response trend between thrombin-antithrombin III complex and spontaneous preterm birth before 34 weeks (P.01) and 34 to 36 weeks (P=.03).There is evidence of early pregnancy systemic fibrinolysis among women with spontaneous preterm birth before 34 weeks of gestation independent of inflammation and dyslipidemia, perhaps secondary to microvascular injury.II.

OBJECTIVE To estimate whether placental pathological lesions from an index preterm birth are associated with an increased risk of recurrent preterm birth and to estimate whether certain pathologic lesions recur in a woman's next delivery. METHODS We performed a retrospective cohort study of all women who delivered at less than 37 weeks and had their next delivery at our institution during a 5-year period. Women were included in the cohort if placental pathology was available from their preterm birth. Placental pathology from their subsequent birth was also collected. Placental pathology was classified into presence or absence of two classes of lesions-inflammatory and thrombotic. Variables considered as possible confounders included race, gestational age of preterm birth, interpregnancy interval, tobacco use, payor status, years of education, and maternal medical problems. RESULTS Inflammatory lesions (n=173) were associated with recurrent preterm birth overall as well as recurrent spontaneous preterm birth (P

To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs.From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery.Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter.Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy.II.

OBJECTIVE: To estimate success rates and risks with a trial of labor after one previous cesarean delivery for multifetal gestation compared with one previous cesarean delivery for a singleton pregnancy. METHODS: Patients from the National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network Cesarean Registry with one previous cesarean delivery and a current term singleton pregnancy were identified. Cases had one previous cesarean delivery for a multifetal pregnancy. Controls had one previous cesarean delivery for a singleton pregnancy. RESULTS: Of cases, 556 of 944 (58.9%) attempted a trial of labor. Of controls, 13,923 of 29,329 (47.5%) attempted a trial of labor. The trial of labor success rate was 85.6% among cases and 73.1% among controls (odds ratio 2.19, 95% confidence interval 1.72-2.78). Compared with trial of labor controls, cases had no statistically increased risk of transfusion, endometritis, intensive care unit admissions, uterine rupture, or perinatal complications. Cases in this analysis with a successful trial of labor were more likely to have previously had a successful vaginal birth after cesarean (37.1% compared with 14.1%, P