Risk and Protective Factors for Preterm Birth Among Racial, Ethnic, and Socioeconomic Groups in California.

Importance: Preterm birth (PTB) (gestational age <37 weeks) is a major cause of infant mortality and morbidity in the US and is marked by racial and ethnic and socioeconomic inequities. Further research is needed to elucidate the association of risk and protective factors with trends in PTB rates and with related inequities. Objective: To describe the association of PTB rates with inequities as well as related risk and protective factors over the past decade in a US population-based cohort. Design, Setting, and Participants: This retrospective cohort study of singleton live births in California from January 1, 2011, to December 31, 2022, was conducted using vital statistics records and hospital records. The cohort included births with a gestational age of 22 to 44 weeks. Main Outcomes and Measures: Preterm birth rates by racial and ethnic group and by public and nonpublic insurance (considered as a proxy for socioeconomic status) were studied across years. Log-linear regression (relative risks with 95% CIs) was used to evaluate risk and protective factors within groups. Associations of PTB rates with risk and protective factors were assessed. Results: This study included 5 431 018 singleton live births to individuals who identified as American Indian or Alaska Native (0.3%), Asian (14.2%), Black (4.9%), Hispanic (47.8%), or White (27.0%). A total of 43.1% of births were to individuals with public health insurance. From 2011 to 2022, the overall PTB rate increased from 6.8% to 7.5% (change [SE], 10.6% [0.6%]; z score of 18.5; P < .001). Differences in PTB rates and associated changes were observed for racial and ethnic groups and insurance groups. For example, 2022 PTB rates ranged from 5.8% among White individuals with nonpublic insurance to 11.3% among Black individuals with public health insurance. From 2011 to 2022, PTB rates decreased from 9.1% to 8.8% (change [SE], -3.5% [4.2]; z score of -0.8; P = .42) among Black individuals with nonpublic insurance, whereas they increased from 6.4% to 9.5% (change [SE], 49.8% [16.0%]; z score of 3.1; P = .002) among American Indian or Alaska Native individuals with nonpublic insurance. Increases in some risk factors (eg, preexisting diabetes, sexually transmitted infections, mental health conditions) were observed in most groups, and decreases in some protective factors (eg, participation in the California Women, Infants, and Children program) (P for trend < .001 from 2011 to 2021) were observed mostly in low-income groups. Conclusions and Relevance: In this cohort study of singleton live births in California, PTB rates increased in many groups. Persistent racial and ethnic and socioeconomic inequities were also observed. Changes in risk and protective factors provided clues to patterns of PTB. These data point to an urgent need to address factors associated with PTB at both the individual and population levels.

First-Trimester Cell-Free DNA Fetal Fraction and Birth Weight in Twin Pregnancies.

BACKGROUND: The relationship between fetal fraction and birth weight in twin gestations is poorly understood. OBJECTIVE: To investigate the relationship between first trimester cfDNA fetal fraction and birth weight < 10th percentile in twin gestations. STUDY DESIGN: This is a planned secondary analysis of the Twin cfDNA Study, a 17-center retrospective cohort of twin pregnancies screened for aneuploidy using cfDNA in the first trimester from 12/2011 - 2/2022, excluding those with positive screen results for chromosomal aneuploidy. CfDNA testing was performed by a single lab using massively parallel sequencing (MPSS). Baseline characteristics and birth weight of pregnancies with normal fetal fraction were compared to those with low (<5%) and high (>95%) fetal fraction using univariable analyses and multivariable regression. RESULTS: A total of 1041 twin pregnancies were included. Chronic hypertension, elevated BMI, and self-identified Black race were associated with fetal fraction <5th percentile. There was no difference in median fetal fraction between those with birth weight <10th percentile in at least one twin (median [IQR] fetal fraction 12.2% [9.8, 14.8] versus those with normal birth weight (10th percentile) in both twins (median [IQR] fetal fraction 12.3% [9.7, 15.2] for normal birth weight, p = 0.49). There was no association between high or low fetal fraction and birth weight <10th percentile for one (p=0.45) or both (p=0.81) twins, and there was no association between high or low fetal fraction and birth weight <5th percentile for one (p=0.44) or both (p=0.74) twins. The results were unchanged after adjustment for potential confounders. CONCLUSION: In this large cohort, there was no association between the extremes of cfDNA fetal fraction and birthweight < 10th percentile, suggesting that first trimester fetal fraction may not predict impaired fetal growth in twin gestations.

Utilization of Immediate Postpartum Contraception and Its Association with Interpregnancy Interval: 10-Year Experience at a Single Center.

OBJECTIVE: Increasing availability of immediate postpartum long-acting reversible contraception (LARC) has added contraceptive alternatives to bilateral tubal ligation (BTL) in the immediate postpartum period. The resultant access to long-term contraception has provided patients with improved control over the timing of pregnancies. Our objective is to evaluate changes in the utilization of immediate postpartum contraceptive methods over a 10-year period and its association with interpregnancy interval (IPI). STUDY DESIGN: Retrospective cohort study of 36,445 patients delivered at a single academic hospital center from 2012 to 2020. Deliveries <23 weeks gestation and patients who underwent a cesarean hysterectomy or postpartum hysterectomy for obstetric indications were excluded. The primary outcome was the utilization of postpartum BTL, intrauterine devices, contraceptive implants, and Depo-Provera over the study time period. The secondary outcomes were IPI and interdelivery interval (IDI). Outcomes were compared using appropriate tests of trend. We adjusted for significant covariates as assessed in baseline characteristics. RESULTS: A total of 35,281 patients were included in our study. Groups were different in baseline characteristics including age, race/ethnicity, parity, BMI, insurance status, comorbidity risk, and attendance at postpartum exam. Over the study period, there was a significant difference in utilization of Depo-Provera, LARC, intrauterine device (IUD), and implant (p < 0.001). There was a significant increase in IPI (p < 0.001) and IDI (p < 0.001). CONCLUSION: We observed a significant increase in utilization of immediate postpartum LARC over the study period which corresponded to a significant increase in IPI and IDI. Our findings emphasize the importance of the availability of immediate postpartum contraception as well as its effectiveness in improving family planning options for reproductive-aged patients. We found significantly increased IPI and IDI associated with increased utilization of long-acting reversible contraceptives immediately postpartum. Our findings emphasize the importance of providers offering these options to patients as well as being comfortable initiating immediate postpartum contraception. KEY POINTS: · Immediate postpartum LARC access has increased over the past 10 years.. · Access to more methods of contraception allows patients more options for family planning.. · Increased utilization of LARC led to increased IPI and IDI..

A More Selective vs a Standard Risk-Stratified, Heparin-Based, Obstetric Thromboprophylaxis Protocol.

Importance: In 2016, our institution adopted a pregnancy-related venous thromboembolism (VTE) prophylaxis protocol based on American College of Obstetricians and Gynecologists guidelines that recommended postpartum heparin-based chemoprophylaxis (enoxaparin) based on a risk-stratified algorithm. In response to increased wound hematomas without significant reduction in VTE using this protocol, a more selective risk-stratified approach was adopted in 2021. Objective: To evaluate outcomes of the more selective risk-stratified approach to heparin-based obstetric thromboprophylaxis (enoxaparin) protocol. Design, Setting, and Participants: Retrospective observational study of 17 489 patients who delivered at a single tertiary care center in the southeast US between January 1, 2016, and December 31, 2018 (original protocol), and between December 1, 2021, and May 31, 2023 (more selective protocol). Patients receiving outpatient anticoagulation for active VTE or high VTE risk during pregnancy were excluded. Exposure: Standard risk-stratified and more selective postpartum VTE chemoprophylaxis protocols. Main Outcomes and Measures: The primary outcome was clinical diagnosis of wound hematoma up to 6 weeks pos tpartum. The secondary outcome was new diagnosis of VTE up to 6 weeks post partum. We compared baseline characteristics and outcomes between groups and estimated adjusted odds ratios with 95% CIs of primary and secondary outcomes using the original protocol group as reference. Results: Of 17 489 patients included in the analysis, 12 430 (71%) were in the original protocol group and 5029 (29%) were in the more selective group. Rates of chemoprophylaxis decreased from 16% (original protocol) to 8% (more selective protocol). Patients in the more selective group were more likely to be older, be married, and have obesity or other comorbidities (hypertension, diabetes, cardiac disease). Compared with the original protocol, the more selective protocol was associated with a decrease in any wound hematoma (0.7% vs 0.3%; adjusted odds ratio [aOR], 0.38; 95% CI, 0.21-0.67), specifically due to a lower rate of superficial wound hematomas (0.6% vs 0.3%; aOR, 0.43; 95% CI, 0.24-0.75). There was no significant increase in VTE or individual types of VTE (0.1% vs 0.1%; aOR, 0.40; 95% CI, 0.12-1.36). Conclusions and Relevance: A more selective risk-stratified approach to an enoxaparin thromboprophylaxis protocol for VTE was associated with decreased rates of wound hematomas without increased rates of postpartum VTE.

Postpartum Outcomes in Patients Receiving Venous Thromboembolism Prophylaxis during Antepartum Admission.

OBJECTIVE: We evaluated if venous thromboembolism (VTE) prophylaxis in the inpatient antepartum period was associated with wound hematomas, VTE occurrence, and other adverse outcomes. STUDY DESIGN: This study is a secondary analysis of a retrospective cohort of patients who delivered at University of Alabama at Birmingham (UAB). Patients receiving outpatient anticoagulation (AC) were excluded. We grouped patients into those who received inpatient antepartum prophylactic AC and those who did not. The primary outcome was wound hematomas from delivery to 6 weeks postpartum (PP). Secondary outcomes included VTE occurrence and select adverse outcomes, including other wound complications, unplanned procedures, mode of anesthesia, and intensive care unit (ICU) admission. Analyses were performed with no AC group as the reference. A sensitivity analysis excluding those who received inpatient PP AC was performed. RESULTS: Of 1,035 included patients, only 169 patients received inpatient prophylactic AC. They were older, had higher body mass indices, and more comorbidities. Patients receiving inpatient antepartum AC had higher wound hematomas (adjusted odds ratio [aOR] 23.81; 95% confidence interval [CI] 7.04-80.47). They had similar risk for developing VTE as the control group (aOR 2.68; 95% CI 0.19-37.49) but were more likely to have wound complications (aOR 2.36; 95% CI 1.24-4.47), maternal deaths (p < 0.05), and require PP ICU admission (aOR 13.38; 95% CI 4.79-37.35). When excluding those receiving any PP AC, there was no difference in bleeding complications between the two groups and VTE rates remained unchanged. Rates of maternal deaths and PP ICU admissions remained higher in those who received inpatient antepartum AC prophylaxis. CONCLUSION: In this small cohort study, increased wound hematomas were found in those who received inpatient antepartum AC prophylaxis with no difference in VTE occurrence. While adverse events were increased in the inpatient AC group, this was mostly associated with PP AC prophylaxis. Larger studies should be conducted to describe the true benefits and risks of antepartum AC prophylaxis and determine efficacy of this widely used practice. KEY POINTS: · Peripartum chemoprophylaxis is associated with increased wound hematomas.. · VTE is rare, despite its association with significant peripartum morbidity/mortality.. · Large studies are needed to guide practices that optimize the risk/benefit ratio of chemoprophylaxis..

Recurrent Severe Maternal Morbidity in an Obstetric Population With a High Comorbidity Burden.

OBJECTIVE: To evaluate the risk of severe maternal morbidity (SMM) in subsequent pregnancies in patients who experienced SMM in a previous pregnancy compared with those who did not. METHODS: We conducted a retrospective cohort study of patients with two or more deliveries at 23 or more weeks of gestation at a single Southeastern U.S. tertiary care center between 2015 and 2018. The primary exposure was SMM including transfusion (transfusion SMM) in a previous pregnancy, as defined by the Centers for Disease Control and Prevention, using International Classification of Diseases, Ninth or Tenth Revision codes. The primary outcome was transfusion SMM in any subsequent pregnancy in the study time frame. Generalized estimating equation models were used to estimate the relative risk (RR) and associated 95% CIs of transfusion SMM in patients with transfusion SMM in a prior pregnancy compared with patients without transfusion SMM in a previous pregnancy. Severe maternal morbidity without transfusion (nontransfusion SMM) and cross-analysis to determine risk of a different type of SMM after a history of SMM were analyzed similarly. RESULTS: Of 852 included patients, transfusion SMM and nontransfusion SMM occurred in 90 (10.6%) and 18 (2.1%), respectively, in the first captured pregnancy and in 79 (9.3%) and 9 (1.1%), respectively, in subsequent pregnancies. Anemia (34.6-40.0%), obesity (33.4-40.4%), substance use disorder (14.2-14.6%), and preeclampsia (12.0-11.4%) were the most prevalent morbidities at first captured and subsequent pregnancies, respectively. There was a 16-fold higher risk of transfusion SMM in a subsequent pregnancy after experiencing transfusion SMM in the first captured pregnancy (57.8% vs 3.5%, RR 16.3 95% CI, 10.8-24.6). Nontransfusion SMM was similarly higher in patients with nontransfusion SMM in their first captured pregnancy compared with those without (16.7% vs 0.7%, RR 23.2 95% CI, 6.3-85.4). Additionally, patients who experienced transfusion SMM in their first captured pregnancies were at sixfold higher risk of developing nontransfusion SMM in a subsequent pregnancy (RR 6.2, 95% CI, 1.7-22.6). However, in cross-analysis of patients who experienced nontransfusion SMM, the risk of transfusion SMM in a subsequent pregnancy was not statistically significant. CONCLUSION: The risks of SMM in subsequent pregnancies after previous SMM are extremely high and are higher than previous estimates. Future studies should estimate the contributions of comorbidities and other structural determinants including social vulnerability to help design interventions to reduce subsequent pregnancy risks.

Physiologic Treatment of Severe Hypertension in Pregnancy and Postpartum.

We aimed to evaluate physiologic treatment of severe hypertension. This was a retrospective cohort study of pregnant and postpartum patients with severe hypertension (systolic blood pressure [BP] 160 mm Hg or higher or diastolic BP 110 mm Hg or higher) treated with intravenous labetalol or hydralazine at a single tertiary care center between 2013 and 2018. Patients were classified as having physiologic treatment if they had hyperdynamic physiology (pulse pressure 65 mm Hg or higher) and received labetalol or had vasoconstrictive physiology (diastolic BP 100 mm Hg or higher) and received hydralazine. The primary outcome was number of antihypertensive doses to achieve nonsevere BP. Of 1,120 patients included in the analysis, 653 had physiologic treatment and 467 had nonphysiologic treatment, with 16 (1.4%) excluded for inability to classify physiology. Physiologic treatment was associated with fewer antihypertensive doses (1.4±0.9 doses vs 1.6±1.4 doses; adjusted ß -0.28, 95% CI, -0.42 to -0.14) and lower odds of medication conversion (2.5% vs 4.7%; adjusted odds ratio 0.48, 95% CI, 0.24-0.93) but no difference in time to nonsevere BP (31 minutes [interquartile range 16-66 minutes] vs 34 minutes [interquartile range 15-76 minutes]; adjusted hazard ratio 1.0, 95% CI, 0.9-1.2). Physiologic treatment of severe hypertension warrants further evaluation.

Predicting peripartum infection in laboring patients at high risk in Cameroon, Africa.

OBJECTIVE: To develop a predictive model for peripartum infection among high risk laboring patients in Cameroon, Africa. STUDY DESIGN: We conducted a secondary analysis of the Cameroon Antibiotic Prophylaxis Trial (NCT03248297), a multicenter 3-arm double-blind randomized controlled trial of oral azithromycin ± amoxicillin among term pregnancies with prolonged labor or rupture of membranes in Cameroon 1/2018-5/2020. Patients with chorioamnionitis prior to randomization, study drug contraindications, or planned cesarean were excluded. The outcome of interest was a composite of maternal peripartum infection (chorioamnionitis, endometritis, sepsis by World Health Organization criteria, wound infection/abscess) diagnosed up to 6 weeks postpartum. Potential predictors were compared between patients with and without the composite outcome, and evaluated at a 0.05 alpha level. Statistically significant exposures were analyzed using multivariable regression (to generate adjusted odds ratios and 95 % confidence intervals) with backwards selection to generate a parsimonious model. Receiver operating characteristic curves with associated area under the curve assessed the model's predictive ability. A nomogram based on the final best fit multivariable model was constructed. RESULTS: Of 756 patients in the parent trial, 652 were analyzed: 45 (7 %) had peripartum infection. Those with infection were more likely to be nulliparous, lower education level, higher gestational age, receive antibiotics per hospital protocols, and undergo cesarean. In our best-fit multivariable model, none/primary education (vs university), cesarean birth, and antibiotic receipt per physician discretion (vs for cesarean prophylaxis) were significantly associated with increased infection risk. This model was moderately predictive (AUC = 0.75, 95 % CI 0.67-0.82). When using this 3 factor model, for a patient with a cesarean birth, receipt of antibiotics per physician discretion, and university education, the probability of peripartum infection was 35 % (95 % CI 0.11-0.73). CONCLUSIONS: While several variables such as parity are associated with infectious morbidity within 6 weeks among high risk laboring patients in Cameroon, only education level, antibiotic indication, and cesarean birth were independently associated, and a model including these 3 factors was moderately predictive. Validation of our findings in a larger population is warranted.

Outcomes in low-risk patients before and after an institutional policy offering 39-week elective induction of labor.

OBJECTIVE: Elective induction of labor versus expectant management at 39 weeks gestation in low-risk nulliparous patients was shown in the ARRIVE randomized trial of over 6000 patients to decrease risks of cesarean delivery without significant change in the composite perinatal outcome. We aimed to pragmatically analyze the effect of offering elective induction of labor (eIOL) to all low-risk patients. METHODS: Retrospective cohort study of low-risk nulliparous and multiparous patients delivering live, non-anomalous singletons at a single center at greater than or equal to 39 0/7 weeks gestational age. Those with prior or planned cesarean delivery, ruptured membranes, medical comorbidities, or contraindications to vaginal delivery were excluded. Patients were categorized as before (pre-eIOL; 1/2012-3/2014) or after (post-eIOL; 3/2019-12/2021) an institution-wide policy offering eIOL at 39 0/7 weeks. Births occurring April 2014 to December 2018 were allocated to a separate cohort (during-eIOL) given increased exposure to eIOL as our center recruited participants for the ARRIVE trial. The primary outcome was cesarean birth. Secondary outcomes included select maternal (e.g. chorioamnionitis, operative delivery, postpartum hemorrhage) and neonatal morbidities (e.g. birthweight, small- and large-for gestational age, hypoglycemia). Characteristics and outcomes were compared between the pre and during-eIOL, and pre and post-eIOL groups; adjusted OR (95% CI) were calculated using multivariable regression. Subgroup analysis by parity was planned. RESULTS: Of 10,758 patients analyzed, 2521 (23.4%) were pre-eIOL, 5410 (50.3%) during-eIOL, and 2827 (26.3%) post-eIOL. Groups differed with respect to labor type, age, race/ethnicity, marital and payor status, and gestational age at care entry. Post-eIOL was associated with lower odds of cesarean compared to pre-eIOL (aOR 0.83 [95% CI 0.72-0.96]), which was even lower among those specifically undergoing labor induction (aOR 0.58 [0.48-0.70]. During-eIOL was also associated with lower odds of cesarean compared to pre-eIOL (aOR 0.79 [0.69-0.90]). Both during and post-eIOL groups were associated with higher odds of chorioamnionitis, operative delivery, and hemorrhage compared to pre-eIOL. However, only among post-eIOL were there fewer neonates weighing ≥4000 g, large-for-gestational age infants, and neonatal hypoglycemia compared to pre-IOL. CONCLUSION: An institutional policy offering eIOL at 39 0/7 to low-risk patients was associated with a lower cesarean birth rate, lower birthweights and lower neonatal hypoglycemia, and an increased risk of chorioamnionitis and hemorrhage.

Delivery outcomes in the subsequent pregnancy following the conservative management of placenta accreta spectrum disorder: a systematic review and meta-analysis.

OBJECTIVE: Cesarean hysterectomy is generally presumed to decrease maternal morbidity and mortality secondary to placenta accreta spectrum disorder. Recently, uterine-sparing techniques have been introduced in conservative management of placenta accreta spectrum disorder to preserve fertility and potentially reduce surgical complications. However, despite patients often expressing the intention for future conception, few data are available regarding the subsequent pregnancy outcomes after conservative management of placenta accreta spectrum disorder. Thus, we aimed to perform a systematic review and meta-analysis to assess these outcomes. DATA SOURCES: PubMed, Scopus, and Web of Science databases were searched from inception to September 2022. STUDY ELIGIBILITY CRITERIA: We included all studies, with the exception of case studies, that reported the first subsequent pregnancy outcomes in individuals with a history of placenta accreta spectrum disorder who underwent any type of conservative management. METHODS: The R programming language with the "meta" package was used. The random-effects model and inverse variance method were used to pool the proportion of pregnancy outcomes. RESULTS: We identified 5 studies involving 1458 participants that were eligible for quantitative synthesis. The type of conservative management included placenta left in situ (n=1) and resection surgery (n=1), and was not reported in 3 studies. The rate of placenta accreta spectrum disorder recurrence in the subsequent pregnancy was 11.8% (95% confidence interval, 1.1-60.3; I2=86.4%), and 1.9% (95% confidence interval, 0.0-34.1; I2=82.4%) of participants underwent cesarean hysterectomy. Postpartum hemorrhage occurred in 10.3% (95% confidence interval, 0.3-81.4; I2=96.7%). A composite adverse maternal outcome was reported in 22.7% of participants (95% confidence interval, 0.0-99.4; I2=56.3%). CONCLUSION: Favorable pregnancy outcome is possible following successful conservation of the uterus in a placenta accreta spectrum disorder pregnancy. Approximately 1 out of 4 subsequent pregnancies following conservative management of placenta accreta spectrum disorder had considerable adverse maternal outcomes. Given such high incidence of adverse outcomes and morbidity, patient and provider preparation is vital when managing this population.

Umbilical Cord Milking Versus Delayed Cord Clamping in Infants 28 to 32 Weeks: A Randomized Trial.

OBJECTIVES: To determine whether rate of severe intraventricular hemorrhage (IVH) or death among preterm infants receiving placental transfusion with UCM is noninferior to delayed cord clamping (DCC). METHODS: Noninferiority randomized controlled trial comparing UCM versus DCC in preterm infants born 28 to 32 weeks recruited between June 2017 through September 2022 from 19 university and private medical centers in 4 countries. The primary outcome was Grade III/IV IVH or death evaluated at a 1% noninferiority margin. RESULTS: Among 1019 infants (UCM n = 511 and DCC n = 508), all completed the trial from birth through initial hospitalization (mean gestational age 31 weeks, 44% female). For the primary outcome, 7 of 511 (1.4%) infants randomized to UCM developed severe IVH or died compared to 7 of 508 (1.4%) infants randomized to DCC (rate difference 0.01%, 95% confidence interval: (-1.4% to 1.4%), P = .99). CONCLUSIONS: In this randomized controlled trial of UCM versus DCC among preterm infants born between 28 and 32 weeks' gestation, there was no difference in the rates of severe IVH or death. UCM may be a safe alternative to DCC in premature infants born at 28 to 32 weeks who require resuscitation.

Complete Compared With Partial Salpingectomy for Postpartum Sterilization.

In this narrative review, we describe evidence regarding the associated risks, benefits, and cost effectiveness of postpartum complete salpingectomy compared with partial salpingectomy. Permanent contraception can be performed via several methods, but complete salpingectomy is becoming more common secondary to its coincident benefit of ovarian cancer risk reduction. Small prospective studies and larger retrospective cohort studies have demonstrated the feasibility and safety of complete salpingectomy in the postpartum period. Additionally, multiple cost-effectiveness analyses have demonstrated the cost effectiveness of this method secondary to ovarian cancer reduction over the life span. Although future larger cohort studies will allow for more precise estimates of the effect of complete salpingectomy on ovarian cancer risk and incidence of rare complications, current data suggest that complete salpingectomy should be offered to patients as a method of permanent contraception in the postpartum period.

Meta-analysis reveals the vaginal microbiome is a better predictor of earlier than later preterm birth.

BACKGROUND: High-throughput sequencing measurements of the vaginal microbiome have yielded intriguing potential relationships between the vaginal microbiome and preterm birth (PTB; live birth prior to 37 weeks of gestation). However, results across studies have been inconsistent. RESULTS: Here, we perform an integrated analysis of previously published datasets from 12 cohorts of pregnant women whose vaginal microbiomes were measured by 16S rRNA gene sequencing. Of 2039 women included in our analysis, 586 went on to deliver prematurely. Substantial variation between these datasets existed in their definition of preterm birth, characteristics of the study populations, and sequencing methodology. Nevertheless, a small group of taxa comprised a vast majority of the measured microbiome in all cohorts. We trained machine learning (ML) models to predict PTB from the composition of the vaginal microbiome, finding low to modest predictive accuracy (0.28-0.79). Predictive accuracy was typically lower when ML models trained in one dataset predicted PTB in another dataset. Earlier preterm birth (< 32 weeks, < 34 weeks) was more predictable from the vaginal microbiome than late preterm birth (34-37 weeks), both within and across datasets. Integrated differential abundance analysis revealed a highly significant negative association between L. crispatus and PTB that was consistent across almost all studies. The presence of the majority (18 out of 25) of genera was associated with a higher risk of PTB, with L. iners, Prevotella, and Gardnerella showing particularly consistent and significant associations. Some example discrepancies between studies could be attributed to specific methodological differences but not most study-to-study variations in the relationship between the vaginal microbiome and preterm birth. CONCLUSIONS: We believe future studies of the vaginal microbiome and PTB will benefit from a focus on earlier preterm births and improved reporting of specific patient metadata shown to influence the vaginal microbiome and/or birth outcomes.

Updates in Genetic Screening for the General Obstetrician.

The number of prenatal genetic screening options, including aneuploidy screening and carrier screening, has drastically increased with rapid advancements in DNA sequencing technologies. Noninvasive prenatal screening analyzing cell-free DNA has quickly been integrated into routine prenatal care as it is the most sensitive and specific screening method for pregnancies at increased and average risk of fetal aneuploidy. The aim of this article is to outline current recommendations for cell-free DNA screening and carrier screening, important aspects of pretest and posttest counseling for obstetric providers, and which patients should be referred to a genetic specialist.

Retrospective Evaluation of Mycoplasma genitalium Prevalence and Macrolide Resistance in a Study Cohort of Pregnant Women in Birmingham, AL, From 1997 to 2001.

ABSTRACT: In a prospective study conducted in 2020 to 2021, macrolide resistance-associated mutations were found in 41% of pregnant persons in Birmingham, AL, with Mycoplasma genitalium detected. We retrospectively evaluated M. genitalium in 203 pregnant persons participating in a study conducted in 1997 to 2001 in Birmingham and adjacent areas and found a prevalence of 11% (95% confidence interval, 6.9%-15.7%), but no macrolide resistance-associated mutations.

Prenatal exposure to perceived stress, maternal asthma, and placental size.

INTRODUCTION: Prenatal exposure to stress has been associated with poor pregnancy outcomes, yet evidence linking stress and placental size is limited. Asthma is associated with worse pregnancy outcomes and women with asthma may be more susceptible to stress. Using the asthma-enriched B-WELL-Mom cohort, we examined the association between perceived stress and placental size. METHODS: Placental measures of weight, length, width, and thickness were available for 345 women (262 with asthma) via placental pathology report. Perceived Stress Scale (PSS) scores were obtained in each trimester of pregnancy and categorized into quartiles (low quartile as reference). For associations between PSS and placental size, generalized estimating equations adjusted for maternal and infant factors were used to estimate regression coefficients (ß) and 95% confidence intervals (95% CI). Full models and models stratified by asthma status were run. RESULTS: Compared to Quartile 1, high levels of stress (Quartile 4) were associated with smaller placental weight (-20.63 95% CI: -37.01,-4.26) and length (-0.55 95% CI: -0.96,-0.15), but not width or thickness. Results by asthma status show a stronger association between perceived stress and shorter placental length in those with asthma and a stronger association between perceived stress and smaller placental thickness in those without asthma. Findings were robust to sensitivity analyses DISCUSSION: Higher levels of perceived stress were associated with smaller placental size. Additional research is warranted to understand the relationship between stress and placental size.

Perinatal Morbidity in Healthy Obese Pregnant Individuals Delivered by Elective Repeat Cesarean at Term.

OBJECTIVE: This study aimed to compare the risks of adverse perinatal outcomes by body mass index (BMI) categories in healthy pregnant individuals delivered by term elective repeat cesarean (ERCD) to describe an optimal timing of delivery in otherwise healthy patients at the highest-risk BMI threshold. STUDY DESIGN: A secondary analysis of a prospective cohort of pregnant individuals undergoing ERCD at 19 centers in the Maternal-Fetal Medicine Units Network from 1999 to 2002. Nonanomalous singletons undergoing prelabor ERCD at term were included. The primary outcome was composite neonatal morbidity; secondary outcomes included composite maternal morbidity and individual components of the composites. Patients were stratified by BMI classes and to identify a BMI threshold for which morbidity was the highest. Outcomes were then examined by completed week's gestation, between BMI classes. Multivariable logistic regression was used to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI). RESULTS: A total of 12,755 patients were included in analysis. Patient's with BMI ≥ 40 had the highest rates of newborn sepsis, neonatal intensive care unit admissions, and wound complications. While a weight-related response was observed between BMI class and neonatal composite morbidity (p < 0.001), only those with BMI ≥ 40 had significantly higher odds of composite neonatal morbidity (aOR: 1.4, 95% CI: 1.0-1.8). In analyses of patients with BMI ≥ 40 (n = 1,848), there was no difference in the incidence of composite neonatal or maternal morbidity across weeks' gestation at delivery; however, as gestational age approached 39 to 40 weeks, rates of adverse neonatal outcomes decreased, only to increase again at 41 weeks' gestation. Of note, the odds of the primary neonatal composite were the highest at 38 weeks compared with 39 weeks (aOR: 1.5, 95% CI: 1.1-2.0). CONCLUSION: Neonatal morbidity is significantly higher in pregnant individuals with BMI ≥40 delivering by ERCD. Despite this increased perinatal morbidity, delivery prior to 39 and after 41 weeks in these patients is associated with increased neonatal risks. KEY POINTS: · Obese patients without additional comorbidities have higher rates of neonatal morbidity.. · Patients with BMI ≥ 40 carry the highest odds of poor perinatal outcomes.. · Earlier timing of delivery does not appear to reduce this risk..

Contemporary Trends in Cesarean Delivery Rates and Indications.

OBJECTIVE: This study aimed to describe cesarean delivery rates and indications at a single center in order to assess the impact of the guidelines published by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine on trends in labor management. STUDY DESIGN: This is a retrospective cohort study of patients ≥23 weeks' gestation delivering at a single tertiary care referral center from 2013 to 2018. Demographic characteristics, mode of delivery, and main indication for cesarean delivery were ascertained by individual chart review. Cesarean delivery indications (mutually exclusive) were the following: repeat cesarean delivery, nonreassuring fetal status, malpresentation, maternal indications (e.g., placenta previa or genital herpes simplex virus), failed labor (any stage labor arrest), or other (i.e., fetal anomaly and elective). Polynomial (cubic) regression models were used to model rates of cesarean delivery and indications over time. Subgroup analyses further examined trends in nulliparous women. RESULTS: Of the 24,637 patients delivered during the study period, 24,050 were included in the analysis; 7,835 (32.6%) had a cesarean delivery. The rates of overall cesarean delivery were significantly different over time (p < 0.001), declining to a minimum of 30.9% in 2014 and peaking at 34.6% in 2018. With regard to the overall cesarean delivery indications, there were no significant differences over time. When limited to nulliparous patients, the rates of cesarean delivery were also noted to be significantly different over time (p = 0.02) nadiring at 30% in 2015 from 35.4% in 2013 and then rising up to 33.9% in 2018. As for nulliparous patients, there was no significant difference in primary cesarean delivery indications over time except for nonreassuring fetal status (p = 0.049). CONCLUSION: Despite changes in labor management definitions and guidelines encouraging vaginal birth, the rates of overall cesarean delivery did not decrease over time. The indications for delivery, particularly failed labor, repeat cesarean delivery, and malpresentation have not significantly changed over time. KEY POINTS: · The rates of overall cesarean deliveries did not decrease despite the 2014 published recommendations for the reduction in cesarean deliveries.. · There were no significant differences in the indications of cesarean deliveries among nulliparous or multiparous women.. · Despite the adoption of strategies to reduce the overall and primary cesarean delivery rates, these trends remain unchanged.. · Indications for delivery, particularly failed labor, repeat cesarean delivery, and malpresentation have also not significantly changed over time.. · Additional strategies to encourage and increase vaginal delivery rates must be adopted..

The Association of Periconception Asthma Medication Discontinuation with Adverse Obstetric Outcomes.

OBJECTIVE: This study aimed to investigate asthma medication reduction in the periconceptional period as it relates to asthma status and adverse outcomes in pregnancy. STUDY DESIGN: In a prospective cohort study, self-reported current and past asthma medications were collected and analyzes compared measures of asthma status in women who discontinued asthma medication in the 6 months prior to enrollment ("step-down") versus those who did not ("no change"). Evaluation of asthma was done at three study visits (one per trimester) and by daily diaries, including measures of lung function (percent predicted forced expiratory volume in 1 and 6 s [%FEV1, %FEV6], peak expiratory flow [%PEF], forced vital capacity [%FVC], FEV1 to FVC ratio [FEV1/FVC]), lung inflammation (fractional exhaled nitric oxide [FeNO], ppb), rate of asthma symptoms (activity limitation, night symptoms, rescue inhaler use, wheeze, shortness of breath, cough, chest tightness, chest pain), and rate of asthma exacerbations. Adverse pregnancy outcomes were also evaluated. Adjusted regression analyses examined whether adverse outcomes differed by periconceptional asthma medication changes. RESULTS: Of 279 participants included in analyses, 135 (48.4%) did not change asthma medication in the periconceptional period, whereas 144 (51.6%) reported a step down in medication. Those in the step-down group were more likely to have milder disease (88 [61.1%] in the step-down vs. 74 [54.8%] in the no change group), exhibited less activity limitation (rate ratio [RR]: 0.68, 95% confidence interval [CI]: 0.47-0.98), and experienced fewer asthma attacks (RR: 0.53, 95% CI: 0.34-0.84) during pregnancy. The step-down group had a nonsignificant increase in overall odds of experiencing an adverse pregnancy outcome (odds ratio: 1.62, 95% CI: 0.97-2.72). CONCLUSION: Over half of women with asthma reduce asthma medication in the periconceptional period. Although these women typically have milder disease, a step down in medication may be associated with an increased risk of adverse pregnancy outcomes. KEY POINTS: · Many women reduce their asthma medication in pregnancy.. · Reduction is more common among those with mild disease.. · Medication reduction may lead to adverse pregnancy outcomes..

Predicting Spontaneous Labor beyond 39 Weeks among Low-Risk Expectantly Managed Pregnant Patients.

OBJECTIVES: The aim of the study was to identify the characteristics associated with spontaneous labor onset in pregnant patients undergoing expectant management at greater than 39 weeks' gestation and delineate perinatal outcomes associated with spontaneous labor compared with labor induction. STUDY DESIGN: This was a retrospective cohort study of singleton pregnancies at ≥390/7 weeks' gestation delivered at a single center in 2013. The exclusion criteria were elective induction, cesarean delivery or presence of a medical indication for delivery at 39 weeks, more than one prior cesarean delivery, and fetal anomaly or demise. We evaluated prenatally available maternal characteristics as potential predictors of the primary outcome-spontaneous labor onset. Multivariable logistic regression was used to generate two parsimonious models: one with and one without third trimester cervical dilation. We also performed sensitivity analysis by parity and timing of cervical examination, and compared the mode of delivery and other secondary outcomes between patients who went into spontaneous labor and those who did not. RESULTS: Of 707 eligible patients, 536 (75.8%) attained spontaneous labor and 171 (24.2%) did not. In the first model, maternal body mass index (BMI), parity, and substance use were identified as the most predictive factors. Overall, the model did not predict spontaneous labor (area under the curve [AUC]: 0.65; 95% confidence interval [CI]: 0.61-0.70) with high accuracy. The addition of third trimester cervical dilation in the second model did not significantly improve labor prediction (AUC: 0.66; 95% CI: 0.61-0.70; p = 0.76). These results did not differ by timing of cervical examination or parity. Patients admitted in spontaneous labor had lower odds of cesarean delivery (odds ratio [OR]: 0.33; 95% CI: 0.21-0.53) and neonatal intensive care unit (NICU) admission (OR: 0.38; 95% CI: 0.15-0.94). Other perinatal outcomes were similar between the groups. CONCLUSION: Maternal characteristics did not predict spontaneous labor onset at ≥39 weeks' gestation with high accuracy. Patients should be counseled on the challenges of labor prediction regardless of parity and cervical examination, outcomes if spontaneous labor does not occur, and benefits of labor induction. KEY POINTS: · Majority of patients will attain spontaneous labor at ≥39 weeks.. · Maternal characteristics do not predict labor at ≥39 weeks.. · Spontaneous labor has associated lower perinatal risks.. · A shared decision model should be utilized in counseling patients who may choose expectant management..