Preterm neonatal morbidity and mortality by gestational age: a contemporary cohort

BACKGROUND

Although preterm birth <37 weeks' gestation is the leading cause of neonatal morbidity and mortality in the United States, the majority of data regarding preterm neonatal outcomes come from older studies, and many reports have been limited to only very preterm neonates. Delineation of neonatal outcomes by delivery gestational age is needed to further clarify the continuum of mortality and morbidity frequencies among preterm neonates.

OBJECTIVE

We sought to describe the contemporary frequencies of neonatal death, neonatal morbidities, and neonatal length of stay across the spectrum of preterm gestational ages.

STUDY DESIGN

This was a secondary analysis of an obstetric cohort of 115,502 women and their neonates who were born in 25 hospitals nationwide, 2008 through 2011. All liveborn nonanomalous singleton preterm (23.0-36.9 weeks of gestation) neonates were included in this analysis. The frequency of neonatal death, major neonatal morbidity (intraventricular hemorrhage grade III/IV, seizures, hypoxic-ischemic encephalopathy, necrotizing enterocolitis stage II/III, bronchopulmonary dysplasia, persistent pulmonary hypertension), and minor neonatal morbidity (hypotension requiring treatment, intraventricular hemorrhage grade I/II, necrotizing enterocolitis stage I, respiratory distress syndrome, hyperbilirubinemia requiring treatment) were calculated by delivery gestational age; each neonate was classified once by the worst outcome for which criteria was met.

RESULTS

In all, 8334 deliveries met inclusion criteria. There were 119 (1.4%) neonatal deaths. In all, 657 (7.9%) neonates had major morbidity, 3136 (37.6%) had minor morbidity, and 4422 (53.1%) survived without any of the studied morbidities. Deaths declined rapidly with each advancing week of gestation. This decline in death was accompanied by an increase in major neonatal morbidity, which peaked at 54.8% at 25 weeks of gestation. As frequencies of death and major neonatal morbidity fell, minor neonatal morbidity increased, peaking at 81.7% at 31 weeks of gestation. The frequency of all morbidities fell >32 weeks. After 25 weeks, neonatal length of hospital stay decreased significantly with each additional completed week of pregnancy; among babies delivered from 26-32 weeks of gestation, each additional week in utero reduced the subsequent length of neonatal hospitalization by a minimum of 8 days. The median postmenstrual age at discharge nadired around 36 weeks' postmenstrual age for babies born at 31-35 weeks of gestation.

CONCLUSION

Our data show that there is a continuum of outcomes, with each additional week of gestation conferring survival benefit while reducing the length of initial hospitalization. These contemporary data can be useful for patient counseling regarding preterm outcomes.

Disease Severity and Perinatal Outcomes of Pregnant Patients With Coronavirus Disease 2019 (COVID-19)

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<.001 for trend across severity). In adjusted analyses, severe-critical COVID-19 was associated with increased risk of cesarean birth (59.6% vs 34.0%, adjusted relative risk [aRR] 1.57, 95% CI 1.30-1.90), hypertensive disorders of pregnancy (40.4% vs 18.8%, aRR 1.61, 95% CI 1.18-2.20), and preterm birth (41.8% vs 11.9%, aRR 3.53, 95% CI 2.42-5.14) compared with asymptomatic patients. Mild-moderate COVID-19 was not associated with adverse perinatal outcomes compared with asymptomatic patients.

CONCLUSION

Compared with pregnant patients with SARS-CoV-2 infection without symptoms, those with severe-critical COVID-19, but not those with mild-moderate COVID-19, were at increased risk of perinatal complications.

Racial and ethnic differences in preterm birth: A complex, multifactorial problem

Preterm birth remains the leading cause of morbidity and mortality among nonanomalous neonates, and is a major public health problem. Non-Hispanic black women have a 2-fold greater risk for preterm birth compared with non-Hispanic white race. The reasons for this disparity are poorly understood and cannot be explained solely by sociodemographic factors. Underlying factors including a complex interaction between maternal, paternal, and fetal genetics, epigenetics, the microbiome, and these sociodemographic risk factors likely underlies the differences between racial groups, but these relationships are currently poorly understood. This article reviews the epidemiology of disparities in preterm birth rates and adverse pregnancy outcomes and discuss possible explanations for the racial and ethnic differences, while examining potential solutions to this major public health problem.

Association of SARS-CoV-2 Infection With Serious Maternal Morbidity and Mortality From Obstetric Complications

Importance

It remains unknown whether SARS-CoV-2 infection specifically increases the risk of serious obstetric morbidity.

Objective

To evaluate the association of SARS-CoV-2 infection with serious maternal morbidity or mortality from common obstetric complications.

Design, Setting, and Participants

Retrospective cohort study of 14 104 pregnant and postpartum patients delivered between March 1, 2020, and December 31, 2020 (with final follow-up to February 11, 2021), at 17 US hospitals participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Gestational Research Assessments of COVID-19 (GRAVID) Study. All patients with SARS-CoV-2 were included and compared with those without a positive SARS-CoV-2 test result who delivered on randomly selected dates over the same period.

Exposures

SARS-CoV-2 infection was based on a positive nucleic acid or antigen test result. Secondary analyses further stratified those with SARS-CoV-2 infection by disease severity.

Main Outcomes and Measures

The primary outcome was a composite of maternal death or serious morbidity related to hypertensive disorders of pregnancy, postpartum hemorrhage, or infection other than SARS-CoV-2. The main secondary outcome was cesarean birth.

Results

Of the 14 104 included patients (mean age, 29.7 years), 2352 patients had SARS-CoV-2 infection and 11 752 did not have a positive SARS-CoV-2 test result. Compared with those without a positive SARS-CoV-2 test result, SARS-CoV-2 infection was significantly associated with the primary outcome (13.4% vs 9.2%; difference, 4.2% [95% CI, 2.8%-5.6%]; adjusted relative risk [aRR], 1.41 [95% CI, 1.23-1.61]). All 5 maternal deaths were in the SARS-CoV-2 group. SARS-CoV-2 infection was not significantly associated with cesarean birth (34.7% vs 32.4%; aRR, 1.05 [95% CI, 0.99-1.11]). Compared with those without a positive SARS-CoV-2 test result, moderate or higher COVID-19 severity (n = 586) was significantly associated with the primary outcome (26.1% vs 9.2%; difference, 16.9% [95% CI, 13.3%-20.4%]; aRR, 2.06 [95% CI, 1.73-2.46]) and the major secondary outcome of cesarean birth (45.4% vs 32.4%; difference, 12.8% [95% CI, 8.7%-16.8%]; aRR, 1.17 [95% CI, 1.07-1.28]), but mild or asymptomatic infection (n = 1766) was not significantly associated with the primary outcome (9.2% vs 9.2%; difference, 0% [95% CI, -1.4% to 1.4%]; aRR, 1.11 [95% CI, 0.94-1.32]) or cesarean birth (31.2% vs 32.4%; difference, -1.4% [95% CI, -3.6% to 0.8%]; aRR, 1.00 [95% CI, 0.93-1.07]).

Conclusions and Relevance

Among pregnant and postpartum individuals at 17 US hospitals, SARS-CoV-2 infection was associated with an increased risk for a composite outcome of maternal mortality or serious morbidity from obstetric complications.

17-OHPC to Prevent Recurrent Preterm Birth in Singleton Gestations (PROLONG Study): A Multicenter, International, Randomized Double-Blind Trial

BACKGROUND

Women with a history of spontaneous preterm birth (SPTB) are at a significantly increased risk for recurrent preterm birth (PTB). To date, only one large U.S. clinical trial comparing 17-OHPC (17-α-hydroxyprogesterone caproate or "17P") to placebo has been published, and this trial was stopped early due to a large treatment benefit.

OBJECTIVE

This study aimed to assess whether 17-OHPC decreases recurrent PTB and neonatal morbidity in women with a prior SPTB in a singleton gestation.

STUDY DESIGN

This was a double-blind, placebo-controlled international trial involving women with a previous singleton SPTB (clinicaltrials.gov: NCT01004029). Women were enrolled at 93 clinical centers (41 in the United States and 52 outside the United States) between 16^0/7 to 20^6/7 weeks in a 2:1 ratio, to receive either weekly intramuscular (IM) injections of 250 mg of 17-OHPC or an inert oil placebo; treatment was continued until delivery or 36 weeks. Co-primary outcomes were PTB < 35 weeks and a neonatal morbidity composite index. The composite included any of the following: neonatal death, grade 3 or 4 intraventricular hemorrhage, respiratory distress syndrome, bronchopulmonary dysplasia, necrotizing enterocolitis, or proven sepsis. A planned sample size of 1,707 patients was estimated to provide 98% power to detect a 30% reduction in PTB < 35 weeks (30% to 21%) and 90% power to detect a 35% reduction in neonatal composite index (17%-11%) using a two-sided type-I error of 5%. Finally, this sample size would also provide 82.8% power to rule out a doubling in the risk of fetal/early infant death assuming a 4% fetal/early infant death rate. Analysis was performed according to the intention-to-treat principle.

RESULTS

Baseline characteristics between the 1,130 women who received 17-OHPC and 578 women who received placebo were similar. Overall, 87% of enrolled women were Caucasian, 12% had >1 prior SPTB, 7% smoked cigarettes, and 89% were married/lived with partner. Prior to receiving study drug, 73% women had a transvaginal cervical length measurement performed and <2% had cervical shortening <25 mm. There were no significant differences in the frequency of PTB < 35 weeks (17-OHPC 11.0% vs. placebo 11.5%; relative risk = 0.95 [95% confidence interval (CI): 0.71-1.26]) or neonatal morbidity index (17-OHPC 5.6% vs. placebo 5.0%; relative risk = 1.12 [95% CI: 0.68-1.61]). There were also no differences in frequency of fetal/early infant death (17-OHPC 1.7% vs. placebo 1.9%; relative risk = 0.87 [95% CI: 0.4-1.81]. Maternal outcomes were also similar. In the subgroup of women enrolled in the United States (n = 391; 23% of all patients), although the rate of PTB < 35 weeks was higher than the overall study population, there were no statistically significant differences between groups (15.6% vs. 17.6%; relative risk = 0.88 [95% CI: 0.55, 1.40].

CONCLUSION

In this study population, 17-OHPC did not decrease recurrent PTB and was not associated with increased fetal/early infant death.

Effects of psychological stress on adverse pregnancy outcomes and nonpharmacologic approaches for reduction: an expert review

Both acute and chronic stress can cause allostatic overload, or long-term imbalance in mediators of homeostasis, that results in disruptions in the maternal-placental-fetal endocrine and immune system responses. During pregnancy, disruptions in homeostasis may increase the likelihood of preterm birth and preeclampsia. Expectant mothers traditionally have high rates of anxiety and depressive disorders, and many are susceptible to a variety of stressors during pregnancy. These common life stressors include financial concerns and relationship challenges and may be exacerbated by the biological, social, and psychological changes occurring during pregnancy. In addition, external stressors such as major weather events (eg, hurricanes, tornados, floods) and other global phenomena (eg, the coronavirus disease 2019 pandemic) may contribute to stress during pregnancy. This review investigates recent literature published about the use of nonpharmacologic modalities for stress relief in pregnancy and examines the interplay between psychiatric diagnoses and stressors, with the purpose of evaluating the feasibility of implementing nonpharmacologic interventions as sole therapies or in conjunction with psychotherapy or psychiatric medication therapy. Further, the effectiveness of each nonpharmacologic therapy in reducing symptoms of maternal stress is reviewed. Mindfulness meditation and biofeedback have shown effectiveness in improving one's mental health, such as depressive symptoms and anxiety. Exercise, including yoga, may improve both depressive symptoms and birth outcomes. Expressive writing has successfully been applied postpartum and in response to pregnancy challenges. Although some of these nonpharmacologic interventions can be convenient and low cost, there is a trend toward inconsistent implementation of these modalities. Future investigations should focus on methods to increase ease of uptake, ensure each option is available at home, and provide a standardized way to evaluate whether combinations of different interventions may provide added benefit.

The phenotype of spontaneous preterm birth: application of a clinical phenotyping tool

OBJECTIVE

Spontaneous preterm birth (SPTB) is a complex condition that is likely a final common pathway with multiple possible causes. We hypothesized that a comprehensive classification system appropriately could group women with similar STPB causes and could provide an explanation, at least in part, for the disparities in SPTB that are associated with race and gestational age at delivery.

STUDY DESIGN

This was a planned analysis of a multicenter, prospective study of singleton SPTBs. Women with SPTB at <34 weeks' gestation were included. We defined 9 potential SPTB phenotypes based on clinical data: infection/inflammation, maternal stress, decidual hemorrhage, uterine distention, cervical insufficiency, placental dysfunction, premature rupture of the membranes, maternal comorbidities, and familial factors. Each woman's condition was evaluated for each phenotype. Delivery gestational age was compared between those with and without each phenotype. Phenotype profiles were also compared between women with very early (20.0-27.9 weeks' gestation) SPTB vs those with early SPTB (28.0-34.0 weeks' gestation) and between African American and white women. Statistical analysis was by t test and χ(2) test, as appropriate.

RESULTS

The phenotyping tool was applied to 1025 women with SPTBs who delivered at a mean 30.0 ± 3.2 (SD) weeks' gestation. Of these, 800 women (78%) had ≥2 phenotypes. Only 43 women (4.2%) had no phenotypes. The 281 women with early SPTBs were more likely to have infection/inflammation, decidual hemorrhage, and cervical insufficiency phenotypes (all P ≤ .001). African American women had more maternal stress and cervical insufficiency but less decidual hemorrhage and placental dysfunction compared with white women (all P < .05). Gestational age at delivery decreased as the number of phenotypes that were present increased.

CONCLUSION

Precise SPTB phenotyping classifies women with SPTBs and identifies specific differences between very early and early SPTB and between African American and white women.

The "Latina epidemiologic paradox": contrasting patterns of adverse birth outcomes in U.S.-born and foreign-born Latinas

BACKGROUND

The "Latina epidemiologic paradox" postulates that despite socioeconomic disadvantages, Latina mothers have a lower risk for delivering low birth weight (LBW) babies than non-Latina Whites. However, these patterns may be changing over time and may differ depending on the mother's birthplace and legal status in the United States. This study investigates differences in risk for three birth outcomes among Whites, U.S.-born Latinas, and foreign-born Latinas.

METHODS

We undertook a cross-sectional study of rates of LBW, preterm, and small-for-gestational-age (SGA) births among 196,617 women delivering live, singleton births in Utah from 2004 to 2007. Each group was compared using logistic regression.

RESULTS

U.S.-born Latinas had a similar or greater risk for all three outcomes when compared with Whites. Foreign-born Latinas had lower risk for preterm birth (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.80-0.90) compared with Whites, but not for LBW and SGA; foreign-born Latinas had a lower risk for LBW (OR, 0.82; 95% CI, 0.74-0.92), preterm birth (OR, 0.81; 95% CI, 0.74-0.89), and SGA (OR, 0.91; 95% CI, 0.83-0.99) compared with U.S.-born Latinas. Among foreign-born Latinas only, there was no difference in risk between documented (i.e., those who had a legal social security number) and undocumented women for LBW, preterm birth, or SGA.

CONCLUSIONS

These data support the existence of a variation of the "Latina paradox" among Latinas according to birthplace, where U.S.-born Latinas do not experience better birth outcomes than Whites, but foreign-born Latinas experience better birth outcomes for several endpoints compared with U.S.-born Latinas. Prevention efforts may prove more effective by considering the different composition of risk factors among foreign- and U.S.-born Latina populations.

Maternal and fetal morbidity associated with uterine rupture of the unscarred uterus

OBJECTIVE

We sought to report obstetric and neonatal characteristics and outcomes following primary uterine rupture in a large contemporary obstetric cohort and to compare outcomes between those with primary uterine rupture vs those with uterine rupture of a scarred uterus.

STUDY DESIGN

This was a retrospective case-control study. Cases were defined as women with uterine rupture of an unscarred uterus. Controls were women with uterine rupture of a scarred uterus. Demographics, labor characteristics, and obstetric, maternal, and neonatal outcomes were compared. Primary rupture case outcomes were also compared by mode of delivery.

RESULTS

There were 126 controls and 20 primary uterine rupture cases. Primary uterine rupture cases had more previous live births than controls (3.6 vs 1.9; P < .001). Cases were more likely to have received oxytocin augmentation (80% vs 37%; P < .001). Vaginal delivery was more common among cases (45% vs 9%; P < .001). Composite maternal morbidity was higher among primary uterine rupture mothers (65% vs 20%; P < .001). Cases had a higher mean estimated blood loss (2644 vs 981 mL; P < .001) and higher rate of blood transfusion (68% vs 17%; P < .001). Women with primary uterine rupture were more likely to undergo hysterectomy (35% vs 2.4%; P < .001). Rates of major composite adverse neonatal neurologic outcomes including intraventricular hemorrhage, periventricular leukomalacia, seizures, and death were higher in cases (40% vs 12%; P = .001). Primary uterine rupture cases delivering vaginally were more likely to ultimately undergo hysterectomy than those delivering by cesarean (63% vs 9%; P = .017).

CONCLUSION

Although rare, primary uterine rupture is particularly morbid. Clinicians must remain vigilant, particularly in the setting of heavy vaginal bleeding and severe pain.

Screening for spontaneous preterm birth and resultant therapies to reduce neonatal morbidity and mortality: A review

Despite considerable effort aimed at decreasing the incidence of spontaneous preterm birth, it remains the leading cause of perinatal morbidity and mortality. Screening strategies are imperfect. Approaches used to identify women considered by historical factors to be low risk for preterm delivery (generally considered to be women with singleton pregnancies without a history of a previous preterm birth) as well as those at high risk for preterm birth (those with a previous preterm birth, short cervix, or multiple gestation) continue to evolve. Herein, we review the current evidence and approaches to screening women for preterm birth, and examine future directions for clinical practice. Further research is necessary to better identify at-risk women and provide evidence-based management.

Review of the environmental prenatal exposome and its relationship to maternal and fetal health

Environmental chemicals comprise a major portion of the human exposome, with some shown to impact the health of susceptible populations, including pregnant women and developing fetuses. The placenta and cord blood serve as important biological windows into the maternal and fetal environments. In this article we review how environmental chemicals (defined here to include man-made chemicals [e.g., flame retardants, pesticides/herbicides, per- and polyfluoroalkyl substances], toxins, metals, and other xenobiotic compounds) contribute to the prenatal exposome and highlight future directions to advance this research field. Our findings from a survey of recent literature indicate the need to better understand the breadth of environmental chemicals that reach the placenta and cord blood, as well as the linkages between prenatal exposures, mechanisms of toxicity, and subsequent health outcomes. Research efforts tailored towards addressing these needs will provide a more comprehensive understanding of how environmental chemicals impact maternal and fetal health.

Progesterone receptor polymorphisms and clinical response to 17-alpha-hydroxyprogesterone caproate

OBJECTIVE

Seventeen-alpha-hydroxyprogesterone caproate (17-OHPC) reduces recurrent preterm birth (PTB). We hypothesized that single nucleotide polymorphisms in the human progesterone receptor (PGR) affect response to 17-OHPC in the prevention of recurrent PTB.

STUDY DESIGN

We conducted secondary analysis of a study of 17-OHPC vs placebo for recurrent PTB prevention. Twenty PGR gene single nucleotide polymorphisms were studied. Multivariable logistic regression assessed for an interaction between PGR genotype and treatment status in modulating the risk of recurrent PTB.

RESULTS

A total of 380 women were included; 253 (66.6%) received 17-OHPC and 127 (33.4%) received placebo. In all, 61.1% of women were African American. Multivariable logistic regression demonstrated significant treatment-genotype interactions (either a beneficial or harmful treatment response) for African Americans delivering<37 weeks' gestation for rs471767 and rs578029, and for Hispanics/Caucasians delivering<37 weeks' gestation for rs500760 and <32 weeks' gestation for rs578029, rs503362, and rs666553.

CONCLUSION

The clinical efficacy and safety of 17-OHPC for recurrent PTB prevention may be altered by PGR gene polymorphisms.

Correlation between initial neonatal and early childhood outcomes following preterm birth

OBJECTIVE

Neonatal diagnoses are often used as surrogate endpoints for longer-term outcomes. We sought to characterize the correlation between neonatal diagnoses and early childhood neurodevelopment.

STUDY DESIGN

We conducted secondary analysis of a multicenter randomized controlled trial of antenatal magnesium sulfate vs placebo administered to women at imminent risk for delivery <32.0 weeks to prevent death and cerebral palsy in their offspring. Singletons and twins delivering 23.0-33.9 weeks who survived to hospital discharge and had 2-year-old outcome data were included. Those surviving to age 2 years were assessed by trained physicians and the Bayley II Scales of Infant Development Mental Development and Psychomotor Development Indices. Neonatal diagnoses at the time of each baby's initial hospital discharge were examined singly and in combination to determine those most predictive of childhood neurodevelopmental impairment, defined as a childhood diagnosis of moderate/severe cerebral palsy and/or Bayley scores >2 SD below the mean. Data were analyzed by multiple regression models and area under receiver operating characteristic curves.

RESULTS

A total of 1771 children met criteria. Children were delivered at a mean of 29.4 weeks' gestation. In all, 459 (25.9%) had neurodevelopmental impairment. In models controlling for gestational age at delivery, maternal education, maternal race, tobacco/alcohol/drug use during pregnancy, randomization to magnesium, fetal sex, and chorioamnionitis, individual neonatal morbidities were moderately predictive of childhood neurodevelopmental impairment (best model area under receiver operating characteristic curve, 0.68; 95% confidence interval, 0.65-0.71). Combinations of 2, 3, and 4 morbidities did not improve the prediction of neurodevelopmental impairment.

CONCLUSION

Approximately 1 in 4 previously preterm children had neurodevelopmental impairment at age 2 years. Prediction of childhood outcomes from neonatal diagnoses remains imperfect.

Racial Disparities in Prematurity Persist among Women of High Socioeconomic Status

Objectives

Despite persistent racial disparities in preterm birth (PTB) in the US among non-Hispanic (NH) black women compared to NH white women, it remains controversial whether sociodemographic factors can explain these differences. We sought to evaluate whether disparities in PTB persist among NH black women with high socioeconomic status (SES).

Study Design

We conducted a population-based cohort study of all live births in the US from 2015-2017 using birth certificate data from the National Vital Statistics System. We included singleton, non-anomalous live births among women who were of high SES (defined as having ≥ 16 years of education, private insurance, and not receiving Women, Infants and Children [WIC] benefits) and who identified as NH white, NH black, or 'mixed' NH black and white race. The primary outcome was PTB <37 weeks; secondary outcomes included PTB <34 and <28 weeks. In addition, analyses were repeated considering birthweight <2500g as a surrogate for preterm birth <37 weeks, birthweight <1500g as a surrogate for preterm birth <34 weeks, and birthweight <750g as a surrogate for preterm birth <28 weeks' gestation. Data were analyzed with chi-square, t-test, and logistic regression.

Results

2,170,686 live births met inclusion criteria, with 92.9% NH white, 6.7% NH black, and 0.4% both NH white and black race. Overall, 5.9% delivered <37, 1.3% <34, and 0.3 % <28 weeks. In unadjusted analyses of women with high SES, the PTB rate at each gestational age cutoff was higher for women of 'mixed' NH white and black race, and highest for women who were NH black only compared to women who were NH white only. In regression models we further adjusted for women with insurance and prenatal care their entire pregnancy, maternal race was associated with higher odds of PTB at each GA cutoff, with the highest odds observed at <28 weeks. Finally, in further adjustement analysis including only the 1,934,912 women who received prenatal care in the first trimester, findings were similar. Rates of preterm birth at each gestational age cutoff remained highest for women who identified as non-Hispanic black, intermediate for women identifying as both non-Hispanic black and white race, and lowest for non-Hispanic white women at <37 weeks (9.9% vs. 6.1% vs. 5.5%, respectively; p<0.001), <34 weeks (3.5% vs. 1.5% vs. 1.1%, respectively; p<0.001), and <28 weeks' gestation (1.2% vs. 0.4% vs. 0.2%, respectively, p<0.001).

Conclusions

Even among college-educated women with private insurance who are not receiving WIC, racial disparities in prematurity persist. These national findings are consistent with prior studies that suggest factors other than socio-demographics are important in the underlying pathogenesis of PTB.

Risk factors for unscheduled delivery in patients with placenta accreta

OBJECTIVE

Patients with suspected placenta accreta have improved outcomes with scheduled delivery. Our objective was to identify risk factors for unscheduled delivery in patients with suspected placenta accreta.

STUDY DESIGN

This was a cohort study of women with antenatally suspected placenta accreta. Women who delivered prior to a planned delivery date were compared with women who had a scheduled delivery. Data were analyzed using a Student t test, χ(2), logistic regression, and survival analyses. Variables included in the analyses were episodes of antenatal vaginal bleeding, preterm premature rupture of membranes (PPROM), uterine contractions, prior cesarean deliveries, interpregnancy interval, parity, and patient demographic factors. A value of P < .05 was considered significant.

RESULTS

Seventy-seven women with antenatal suspicion for placenta accreta were identified. Thirty-eight (49.4%) had an unscheduled delivery. Demographics were similar between groups. Unscheduled patients delivered earlier (mean 32.3 vs 35.7 weeks, P < .001) and were significantly more likely to have had vaginal bleeding (86.8% vs 35.9%, P < .001) and uterine activity (47.4% vs 2.6%, P < .001). Each episode of antenatal vaginal bleeding was associated with an increased risk of unscheduled delivery (adjusted odds ratio, 3.8; 95% confidence interval, 1.8-7.8). Risk of earlier delivery was even greater when associated with PPROM (P < .001).

CONCLUSION

Among women with suspected placenta accreta, those with antenatal vaginal bleeding were more likely to require unscheduled delivery. This risk increases further in the setting of PPROM and/or uterine contractions. These clinical factors should be considered when determining the optimal delivery gestational age for women with placental accreta.

Prenatal and Perinatal Determinants of Lung Health and Disease in Early Life: A National Heart, Lung, and Blood Institute Workshop Report

Human lung growth and development begins with preconception exposures and continues through conception and childhood into early adulthood. Numerous environmental exposures (both positive and negative) can affect lung health and disease throughout life. Infant lung health correlates with adult lung function, but significant knowledge gaps exist regarding the influence of preconception, perinatal, and postnatal exposures on general lung health throughout life. On October 1 and 2, 2015, the National Heart, Lung, and Blood Institute convened a group of extramural investigators to develop their recommendations for the direction(s) for future research in prenatal and perinatal determinants of lung health and disease in early life and to identify opportunities for scientific advancement. They identified that future investigations will need not only to examine abnormal lung development, but also to use developing technology and resources to better define normal and/or enhanced lung health. Birth cohort studies offer key opportunities to capture the important influence of preconception and obstetric risk factors on lung health, development, and disease. These studies should include well-characterized obstetrical data and comprehensive plans for prospective follow-up. The importance of continued basic science, translational, and animal studies for providing mechanisms to explain causality using new methods cannot be overemphasized. Multidisciplinary approaches involving obstetricians, neonatologists, pediatric and adult pulmonologists, and basic scientists should be encouraged to design and conduct comprehensive and impactful research on the early stages of normal and abnormal human lung growth that influence adult outcome.

Perinatal outcomes associated with intrahepatic cholestasis of pregnancy. J Matern Fetal Neonatal Med 2017;31:1913-1920. [PMID: 28581354 DOI: 10.1080/14767058.2017.1332036]

OBJECTIVE

The objective of this study is to examine perinatal outcomes associated with cholestasis of pregnancy according to bile acid level and antenatal testing practice.

STUDY DESIGN

Retrospective cohort study of women with symptoms and bile acid testing from 2005 to 2014. Women were stratified by bile acid level: no cholestasis (<10 μmol/L), mild (10-39 μmol/L), moderate (40-99 μmol/L), and severe (≥100 μmol/L). The primary outcome was composite neonatal morbidity (hypoxic ischemic encephalopathy, severe intraventricular hemorrhage, bronchopulmonary dysplasia, necrotizing enterocolitis, or death).

RESULTS

785 women were included; 487 had cholestasis (347 mild, 108 moderate, 32 severe) and 298 did not. After controlling for gestational age (GA), severe cholestasis was associated with the composite neonatal outcome (aRR 5.6, 95% CI 1.3-23.5) and meconium-stained fluid (aRR 4.82, 95%CI 1.6-14.2). Bile acid levels were not correlated with the frequency of testing (p = .50). Women who underwent twice weekly testing were delivered earlier (p = .016) than women tested less frequently, but the difference in GA was ≤4 d. Abnormal testing prompting delivery was uncommon. Among women with cholestasis, there were three stillbirths. One of these women was undergoing antenatal testing, which was normal 1 d prior to the fetal demise.

CONCLUSION

Severe cholestasis is associated with neonatal morbidity which antenatal testing may not predict.

Preterm premature rupture of membranes: does the duration of latency influence perinatal outcomes?

OBJECTIVE

Preterm premature rupture of membranes (PPROM) is the leading identifiable cause of prematurity. We hypothesized that, when controlled for delivery gestational age, potential prolonged exposure to inflammation/infection could be harmful to the developing fetus.

STUDY DESIGN

We studied a retrospective cohort of pregnancies with PPROM at 22.0-33.9 weeks' gestation. The primary outcome was perinatal survival without major morbidity (grade III/IV intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia). Regression models assessed predictors of perinatal morbidity.

RESULTS

Three hundred six women were included. PPROM occurred at a median of 29.4 weeks' gestation (interquartile range [IQR], 24.7-32.1 weeks' gestation). Median latency was 8 days (IQR, 3-15 days). Median delivery age was 31.4 weeks' gestation (IQR, 27.4-33.3 weeks' gestation). Two hundred seventy-seven infants (91%) survived; 233 infants (84% of survivors, 76% of all babies) did not have major morbidities. Gestational age (odds ratio, 0.60; 95% confidence interval, 0.53-0.68) and congenital sepsis (odds ratio, 13.2; 95% confidence interval, 3.9-44.5), but not latency, predicted perinatal morbidity in multivariate models.

CONCLUSION

Latency does not appear to worsen outcomes in pregnancies that are complicated by PPROM.

Optimal timing of antenatal corticosteroid administration and preterm neonatal and early childhood outcomes

Background

Antenatal corticosteroids reduce morbidity and mortality among preterm neonates. However, the optimal timing of steroid administration with regards to severe neonatal and early childhood morbidity is uncertain.

Objective

To evaluate the association between the timing of antenatal corticosteroid adminstration and preterm outcomes. We hypothesized that neonates exposed to antenatal corticosteroids 2 to <7 days before delivery would have the lowest risks of neonatal and childhood morbidity.

Study Design

Secondary analysis of two prospective multicenter studies enriched for spontaneous preterm birth, Genomics and Proteomics Network for Preterm Birth Research (11/2007-1/2011) and Beneficial Effect of Antenatal Magnesium (12/1997-5/2004). We included women with singleton gestations who received antenatal corticosteroids and delivered at 23 0/7-33 6/7 weeks' gestation. Women who received ≥1 course of corticosteroids were excluded. Neonatal outcomes were compared by the timing of the first dose of antenatal corticosteroids in relation to delivery: <2 days, 2 to <7 days, 7 to <14 days, and ≥14 days. The primary outcome was respiratory distress syndrome. Secondary outcomes included composite neonatal morbidity (death, intraventricular hemorrhage grade III or IV, periventricular leukomalacia, bronchopulmonary dysplasia, or necrotizing enterocolitis), and early childhood morbidity (death or moderate to severe cerebral palsy at age 2). Multivariable logistic regression estimated the association between timing of antenatal corticosteroid administration and study outcomes.

Results

A total of 2,259 subjects met inclusion criteria: 622 (27.5%) received antenatal corticosteroids <2 days before delivery, 821 (36.3%) 2 to <7 days, 401 (17.8%) 7 to <14 days, and 415 (18.4%) ≥14 days. The majority (78.1%) delivered following idiopathic spontaneous preterm labor or preterm premature rupture of membranes at a mean gestational age of 29.5 +/-2.8 weeks. Neonates exposed to antenatal corticosteroids 2 to <7 days before delivery were the least likely to develop respiratory distress syndrome (51.3%), compared to those receiving antenatal corticosteroids <2 days, 7 to <14 days, and ≥14 days before delivery (62.7%, 55.9%, and 57.6%, respectively, p<0.001). Compared to receipt 2 to <7 days before delivery, there was an increased odds of respiratory distress syndrome with receipt of antenatal corticosteroids <2 days (aOR 2.07, 95%CI 1.61-2.66), 7 to <14 days (aOR 1.40, 95% CI 1.07-1.83), and ≥14 days (aOR 2.34, 95%CI 1.78-3.07). Neonates exposed to antenatal corticosteroids ≥14 days before delivery were at increased odds for severe neonatal morbidity (aOR 1.57, 95%CI 1.12-2.19) and early childhood morbidity (aOR 1.74, 95%CI 1.02-2.95), compared to those exposed 2 to <7 days before delivery. There was no significant association between antenatal corticosteroid receipt <2 days or 7 to <14 days and severe neonatal morbidity or severe childhood morbidity.

Conclusions

Preterm neonates exposed to antenatal corticosteroids 2 to <7 days before delivery had the lowest odds of respiratory distress syndrome, compared to shorter and longer time intervals between steroid administration and delivery. Antenatal corticosteroid administration ≥14 days before delivery is associated with an increased odds of severe neonatal and childhood morbidity, compared to 2 to <7 days before delivery. These results emphasize the importance of optimally timed antenatal corticosteroids to improve both short- and long-term outcomes.

Effect of interleukin-6 polymorphism on risk of preterm birth within population strata: a meta-analysis

Background

Because of the role of inflammation in preterm birth (PTB), polymorphisms in and near the interleukin-6 gene (IL6) have been association study targets. Several previous studies have assessed the association between PTB and a single nucleotide polymorphism (SNP), rs1800795, located in the IL6 gene promoter region. Their results have been inconsistent and SNP frequencies have varied strikingly among different populations. We therefore conducted a meta-analysis with subgroup analysis by population strata to: (1) reduce the confounding effect of population structure, (2) increase sample size and statistical power, and (3) elucidate the association between rs1800975 and PTB.

Results

We reviewed all published papers for PTB phenotype and SNP rs1800795 genotype. Maternal genotype and fetal genotype were analyzed separately and the analyses were stratified by population. The PTB phenotype was defined as gestational age (GA) < 37 weeks, but results from earlier GA were selected when available. All studies were compared by genotype (CC versus CG+GG), based on functional studies.

For the maternal genotype analysis, 1,165 PTBs and 3,830 term controls were evaluated. Populations were stratified into women of European descent (for whom the most data were available) and women of heterogeneous origin or admixed populations. All ancestry was self-reported. Women of European descent had a summary odds ratio (OR) of 0.68, (95% confidence interval (CI) 0.51 – 0.91), indicating that the CC genotype is protective against PTB. The result for non-European women was not statistically significant (OR 1.01, 95% CI 0.59 - 1.75). For the fetal genotype analysis, four studies were included; there was no significant association with PTB (OR 0.98, 95% CI 0.72 - 1.33). Sensitivity analysis showed that preterm premature rupture of membrane (PPROM) may be a confounding factor contributing to phenotype heterogeneity.

Conclusions

IL6 SNP rs1800795 genotype CC is protective against PTB in women of European descent. It is not significant in other heterogeneous or admixed populations, or in fetal genotype analysis.

Population structure is an important confounding factor that should be controlled for in studies of PTB.

Exposure to toxic metals and per- and polyfluoroalkyl substances and the risk of preeclampsia and preterm birth in the United States: a review

Preeclampsia and preterm birth are among the most common pregnancy complications and are the leading causes of maternal and fetal morbidity and mortality in the United States. Adverse pregnancy outcomes are multifactorial in nature and increasing evidence suggests that the pathophysiology behind preterm birth and preeclampsia may be similar-specifically, both of these disorders may involve abnormalities in placental vasculature. A growing body of literature supports that exposure to environmental contaminants in the air, water, soil, and consumer and household products serves as a key factor influencing the development of adverse pregnancy outcomes. In pregnant women, toxic metals have been detected in urine, peripheral blood, nail clippings, and amniotic fluid. The placenta serves as a "gatekeeper" between maternal and fetal exposures, because it can reduce or enhance fetal exposure to various toxicants. Proposed mechanisms underlying toxicant-mediated damage include disrupted placental vasculogenesis, an up-regulated proinflammatory state, oxidative stressors contributing to prostaglandin production and consequent cervical ripening, uterine contractions, and ruptured membranes and epigenetic changes that contribute to disrupted regulation of endocrine and immune system signaling. The objective of this review is to provide an overview of studies examining the relationships between environmental contaminants in the US setting, specifically inorganic (eg, cadmium, arsenic, lead, and mercury) and organic (eg, per- and polyfluoroalkyl substances) toxicants, and the development of preeclampsia and preterm birth among women in the United States.

Pregnancy outcomes in a recurrent preterm birth prevention clinic

OBJECTIVE

We sought to compare rates of recurrent spontaneous preterm birth (PTB) and neonatal morbidity between women enrolled in a recurrent PTB prevention clinic compared to those receiving usual care.

STUDY DESIGN

This was a retrospective cohort study of women with a single, nonanomalous fetus and ≥1 spontaneous PTB <35 weeks. Women enrolled in a recurrent PTB prevention clinic were compared to those receiving usual care. The recurrent PTB prevention clinic was consultative and included 3 standardized visits. Usual-care patients were treated by their primary provider. The primary outcome was recurrent spontaneous PTB <37 weeks.

RESULTS

Seventy recurrent PTB prevention clinic and 153 usual-care patients were included. Both groups had similar pregnancy histories. Recurrent PTB prevention clinic patients had increased utilization of resources, had lower rates of recurrent spontaneous PTB (48.6% vs 63.4%, P = .04), delivered later (mean 36.1 vs 34.9 weeks, P = .02), and had lower rates of composite major neonatal morbidity (5.7% vs 16.3%, P = .03).

CONCLUSION

Women referred to a consultative recurrent PTB prevention clinic had reduced rates of recurrent spontaneous prematurity and major neonatal morbidity.

Maternal race and intergenerational preterm birth recurrence

BACKGROUND

Preterm birth is a complex disorder with a heritable genetic component. Studies of primarily White women born preterm show that they have an increased risk of subsequently delivering preterm. This risk of intergenerational preterm birth is poorly defined among Black women.

OBJECTIVE

Our objective was to evaluate and compare intergenerational preterm birth risk among non-Hispanic Black and non-Hispanic White mothers.

STUDY DESIGN

This was a population-based retrospective cohort study, using the Virginia Intergenerational Linked Birth File. All non-Hispanic Black and non-Hispanic White mothers born in Virginia 1960 through 1996 who delivered their first live-born, nonanomalous, singleton infant ≥20 weeks from 2005 through 2009 were included. We assessed the overall gestational age distribution between non-Hispanic Black and White mothers born term and preterm (<37 weeks) and their infants born term and preterm (<37 weeks) using Cox regression and Kaplan-Meier survivor functions. Mothers were grouped by maternal gestational age at delivery (term, ≥37 completed weeks; late preterm birth, 34-36 weeks; and early preterm birth, <34 weeks). The primary outcomes were: (1) preterm birth among all eligible births; and (2) suspected spontaneous preterm birth among births to women with medical complications (eg, diabetes, hypertension, preeclampsia and thus higher risk for a medically indicated preterm birth). Multivariable logistic regression was used to estimate odds of preterm birth and spontaneous preterm birth by maternal race and maternal gestational age after adjusting for confounders including maternal education, maternal age, smoking, drug/alcohol use, and infant gender.

RESULTS

Of 173,822 deliveries captured in the intergenerational birth cohort, 71,676 (41.2%) women met inclusion criteria for this study. Of the entire cohort, 30.0% (n = 21,467) were non-Hispanic Black and 70.0% were non-Hispanic White mothers. Compared to non-Hispanic White mothers, non-Hispanic Black mothers were more likely to have been born late preterm (6.8% vs 3.7%) or early preterm (2.8 vs 1.0%), P < .001. Non-Hispanic White mothers who were born (early or late) preterm were not at an increased risk of early or late preterm delivery compared to non-Hispanic White mothers born term. The risk of early preterm birth was most pronounced for Black mothers who were born early preterm (adjusted odds ratio, 3.26; 95% confidence interval, 1.77-6.02) compared to non-Hispanic White mothers.

CONCLUSION

We found an intergenerational effect of preterm birth among non-Hispanic Black mothers but not non-Hispanic White mothers. Black mothers born <34 weeks carry the highest risk of delivering their first child very preterm. Future studies should elucidate the underlying pathways leading to this racial disparity.

Outcomes of expectantly managed pregnancies with multiple gestations and preterm premature rupture of membranes prior to 26 weeks

OBJECTIVE

The objective of the study was to determine the obstetric and neonatal outcomes of expectantly managed multifetal pregnancies complicated by early preterm premature rupture of membranes (PPROM) prior to 26 weeks.

STUDY DESIGN

This was a retrospective cohort of all multifetal pregnancies complicated by documented PPROM occurring before 26 0/7 weeks and managed expectantly by a single maternal-fetal medicine practice between July 4, 2002, and Sept. 1, 2013. Neonatal and maternal outcomes were assessed and comparisons made between the fetus with ruptured membranes and the first fetus to deliver with intact membranes.

RESULTS

Twenty-three pregnancies (46 fetuses) were analyzed with a median gestational age at PPROM of 22.9 weeks; 74% experienced PPROM at less than 24 weeks' gestation. A median latency of 11 days was achieved with expectant management. Of the 46 neonates, 20 (43%) survived to hospital discharge. Of these, 12 (60%) experienced severe neonatal morbidity defined as defined as grade III or IV intraventricular hemorrhage, bronchopulmonary dysplasia, pulmonary hypoplasia, necrotizing enterocolitis requiring surgical intervention, and/or grade 3 or 4 retinopathy of prematurity. Eight neonates survived to hospital discharge without severe neonatal morbidity. The multiple with ruptured membranes was more likely to experience intrauterine demise but otherwise had similar outcomes as the multiple with intact membranes. Maternal morbidity was considerable, with 7 of 23 pregnancies (30%) complicated by clinical chorioamnionitis, 12 of 23 (52%) delivering by cesarean, of which 3 of 12 (25%) were classical cesarean deliveries.

CONCLUSION

Overall, neonatal survival to hospital discharge was 43%, but only 17% survived without significant neonatal morbidity. These data provide a basis for counseling and management of women with multifetal gestation complicated by very early PPROM.

The heritability of gestational age in a two-million member cohort: implications for spontaneous preterm birth

Preterm birth (PTB), defined as birth prior to a gestational age (GA) of 37 completed weeks, affects more than 10% of births worldwide. PTB is the leading cause of neonatal mortality and is associated with a broad spectrum of lifelong morbidity in survivors. The etiology of spontaneous PTB (SPTB) is complex and has an important genetic component. Previous studies have compared monozygotic and dizygotic twin mothers and their families to estimate the heritability of SPTB, but these approaches cannot separate the relative contributions of the maternal and the fetal genomes to GA or SPTB. Using the Utah Population Database, we assessed the heritability of GA in more than 2 million post-1945 Utah births, the largest familial GA dataset ever assembled. We estimated a narrow-sense heritability of 13.3% for GA and a broad-sense heritability of 24.5%. A maternal effect (which includes the effect of the maternal genome) accounts for 15.2% of the variance of GA, and the remaining 60.3% is contributed by individual environmental effects. Given the relatively low heritability of GA and SPTB in the general population, multiplex SPTB pedigrees are likely to provide more power for gene detection than will samples of unrelated individuals. Furthermore, nongenetic factors provide important targets for therapeutic intervention.