Risk Of Late Preterm Birth Research Articles

Betamethasone Exposure and Neonatal Respiratory Morbidity Among Late Preterm Births by Planned Mode of Delivery and Gestational Age.

To estimate the effect of late preterm antenatal steroids on the risk of respiratory morbidity among subgroups of patients on the basis of the planned mode of delivery and gestational age at presentation. This was a secondary analysis of the ALPS (Antenatal Late Preterm Steroid) Trial, a multicenter trial conducted within the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network of individuals with singleton gestations and without preexisting diabetes who were at high risk for late preterm delivery (34-36 weeks of gestation). We fit binomial regression models to estimate the risk of respiratory morbidity, with and without steroid administration, by gestational age and planned mode of delivery at the time of presentation. We assumed a homogeneous effect of steroids on the log-odds scale, as was reported in the ALPS trial. The primary outcome was neonatal respiratory morbidity, as defined in the ALPS Trial. The analysis included 2,825 patients at risk for late preterm birth. The risk of respiratory morbidity varied significantly by planned mode of delivery (adjusted risk ratio [RR] 1.90, 95% CI, 1.55-2.33 for cesarean delivery vs vaginal delivery) and week of gestation at presentation (adjusted RR 0.56, 95% CI, 0.50-0.63). For those planning cesarean delivery and presenting in the 34th week of gestation, the risk of neonatal respiratory morbidity was 39.4% (95% CI, 30.8-47.9%) without steroids and 32.0% (95% CI, 24.6-39.4%) with steroids. In contrast, for patients presenting in the 36th week and planning vaginal delivery, the risk of neonatal respiratory morbidity was 6.9% (95% CI, 5.2-8.6%) without steroids and 5.6% (95% CI, 4.2-7.0%) with steroids. The absolute risk difference of neonatal respiratory morbidity between those exposed and those unexposed to late preterm antenatal steroids varies considerably by gestational age at presentation and planned mode of delivery. Because only communicating the relative risk reduction of antenatal steroids for respiratory morbidity may lead to an inaccurate perception of benefit, more patient-specific estimates of risk expected with and without treatment may inform shared decision making.

19 Neonatal Hypoglycemia in Pregnancies at Risk for Late Preterm Birth: Childhood Neurodevelopmental Outcomes

19 Neonatal Hypoglycemia in Pregnancies at Risk for Late Preterm Birth: Childhood Neurodevelopmental Outcomes

Antenatal Corticosteroid Treatment During the Late-Preterm Period and Neonatal Outcomes for Twin Pregnancies

Antenatal corticosteroid treatment of individuals with singletons at risk for delivery during the late-preterm period has been academically recommended. However, the evidence on the use of antenatal corticosteroid treatment for twins at risk for delivery during the late-preterm period is still lacking. To evaluate whether antenatal corticosteroid treatment during the late-preterm period in twin pregnancies was associated with a lower risk of newborn morbidity. This retrospective cohort study of twin pregnancies delivered from February 1, 2013, to September 30, 2020, in a university-affiliated hospital in China included 1974 individuals with twin pregnancies who were at risk for late preterm birth (34 weeks and 0 days to 36 weeks and 6 days of gestation). Data were analyzed from June 30 to July 13, 2023. Antenatal corticosteroid treatment during the late-preterm period. The primary outcome measure was composite neonatal respiratory morbidity, defined as at least 1 of the following postnatal occurrences in at least 1 neonate of the twins: respiratory distress syndrome, mechanical ventilation, surfactant administration, transferred with respiratory complications, or neonatal death. Propensity score overlap weighting was used to analyze the association between antenatal corticosteroid treatment and the risk of neonatal outcomes. The study population consisted of 1974 individuals with twin pregnancies, including 303 (15.3%; mean [SD] maternal age, 30.8 [4.2] years) who received antenatal corticosteroid treatment and 1671 (84.7%; mean [SD] maternal age, 31.2 [4.0] years) who did not receive antenatal corticosteroid treatment. The propensity score overlap weighting showed no significant differences between the antenatal corticosteroid treatment group and the no-antenatal corticosteroid treatment group in the risk of neonatal primary outcome (29 of 303 [9.6%] vs 41 of 1671 [2.5%]; weighted odds ratio, 1.27 [95% CI, 0.60-2.76]). None of the subgroup interaction tests were significant for the neonatal primary outcome in terms of gestational age at delivery, year of delivery, chorionicity, at least 1 infant small for gestational age, intertwin growth discordance, and infant sex, and neither was the sensitivity analysis of using propensity score matching and a different administration-to-birth interval and treating twin infants as individuals. This cohort study found insufficient evidence that antenatal corticosteroid treatment during the late-preterm period in twin pregnancies could be associated with a lower risk of newborn morbidity. This new finding can provide a reference for clinical practice.

Trajectories of depressive symptoms during pregnancy and risk of premature birth: A multicenter and prospective cohort study

Previous studies only assessed the association between depressive symptoms and risk of preterm birth (PTB) at a time-point during pregnancy, resulting in inconsistent or contradictory results. Therefore, we aimed to explore the associations between the trajectories of depressive symptoms during pregnancy and risk of PTB. In total, 7732 pregnant women were included in 24 hospitals from 15 provinces of China. The Edinburgh Postpartum Depression Scale (EPDS) was used to evaluate depressive symptoms in the first, second, and third trimesters. Associations between depressive symptoms and risk of PTB were performed by group-based trajectory modeling (GBTM), propensity score-based inverse probability of treatment weighting (IPTW), and logistic regression. GBTM identified five trajectories: compared with persistently low-stable trajectory of depressive symptoms, women with moderate-stable (OR = 1.23, 95% CI: 1.02–1.76), high-falling (OR = 1.35, 95% CI: 1.11–2.21), moderate-rising (OR = 1.38, 95% CI: 1.06–2.04), and high-stable trajectory of depressive symptoms (OR = 1.40, 95% CI: 1.16–3.28) had an increased risk of PTB. In addition, the associations between trajectories of depressive symptoms and risk of PTB were most significant in multiparous women with a history of PTB. There was no difference in the risk of early-moderate PTB among different trajectories of depressive symptoms and only the risk of late PTB was different among different trajectories. In conclusion, the depressive symptoms of pregnant women were not constant during pregnancy, and different trajectories of depressive symptoms were associated with different risks of PTB.

Long-Term neurodevelopmental outcome after antenatal corticosteroid in late-preterm twin neonates: nationwide study

In singleton women who are at risk of late preterm delivery, consideration of antenatal corticosteroid is advocated by clinical guidelines to reduce respiratory complications. However, adoption of this practice has not been universal in twin pregnancies at risk for late preterm birth, because of lack of evidences regarding both effectiveness and long-term safety of corticosteroid in this population. In the current study, we evaluated the long-term neurodevelopmental outcome of late-preterm twin neonates after administration of antenatal corticosteroid. This nationwide population-based study included twin neonates who were delivered in late preterm (34∼36+6 weeks) between 2007 and 2010 and were checked for National Health Screening Program for Infants and Children. Group 1 included neonates from mothers who were injected antenatal corticosteroid and group 2 included neonates without antenatal corticosteroid injection. The risk of long-term neurodevelopmental outcome was compared between the two groups of cases. Adverse long-term neurodevelopmental outcome was defined as occurrence of at least one of the followings: autism, cerebral palsy, speech articulation disorder, developmental disorders of scholastic skills, developmental disorder of motor function, and developmental disorder. During the study period, a total of 10,078 neonates were delivered in late preterm and met the inclusion criteria: 2196 neonates in group 1 and 7882 neonates in group 2. In terms of long-term neurodevelopmental outcome, there were no statistically significant difference between the two groups (Figure). The risk of adverse long-term neurodevelopmental outcome was not increased after administration of antenatal corticosteroid at late preterm twin neonates.

Neonatal Respiratory Morbidity after Late Preterm, Singleton, Cesarean Delivery before Labor by Mothers Who Did Not Receive Antenatal Corticosteroids.

Some evidence suggests that administration of antenatal corticosteroids (ACS) reduces neonatal respiratory complications among women at risk for late preterm birth. However, because of concerns regarding long-term outcomes of children, ACS is not recommended in Japan for pregnant women at risk in late preterm. We assessed the risk of neonatal respiratory morbidity after late preterm, singleton, cesarean delivery before labor by mothers who did not receive ACS. We retrospectively reviewed and analyzed data on singleton cesarean deliveries of late preterm infants. The prevalence of neonatal respiratory morbidity requiring ventilatory support, such as continuous positive airway pressure or mechanical ventilation, was analyzed in relation to gestational age in late preterm. Respiratory distress syndrome (RDS) in neonates was also evaluated. We analyzed data from 100 late preterm, singleton, cesarean deliveries: 22 neonates were delivered at 34 weeks, 34 at 35 weeks, and 44 at 36 weeks. Respiratory morbidity significantly decreased in relation to gestational age (p < 0.001). Similarly, there was a significant difference in RDS, which was most frequent at 34 weeks (18.2%, p = 0.017). There were no cases of RDS at 36 weeks. Late preterm, singleton, cesarean delivery before labor in mothers who did not receive ACS was associated with a need for ventilation, especially for infants born at 34 and 35 weeks. ACS treatment might therefore be beneficial before elective cesarean section for mothers with a risk of preterm delivery before 35 weeks and 6 days.

Antenatal dexamethasone use and respiratory distress in late preterm infants: results from first Vietnamese matched cohort study

BackgroundRespiratory distress syndrome (RDS) is one of the leading causes of early neonatal morbidity and mortality in late preterm infants (LPIs) worldwide. This matched cohort study aimed to assess how the antenatal dexamethasone use affect the respiratory distress (RD) proportion in preterm newborns between 34 0/7 weeks and 36 6/7 weeks of gestation.MethodsThis was a prospective cohort study on 78 women with singleton pregnancy who were in threatened preterm birth and had not received prior dexamethasone, who were admitted between 34 0/7 weeks and 36 6/7 weeks at Hue University of Medicine and Pharmacy Hospital from June 2018 to May 2020. The matched control group without dexamethasone use included 78 pregnant women diagnosed with threatened late preterm births who were at similar gestational ages and estimated fetal weights as the treatment group. The treatment group received 6 mg intramuscular dexamethasone every 12 h for a total of 4 doses or until delivery. Primary outcome was the rate of neonatal RD. Secondary neonatal outcomes included the need for respiratory support, neonatal intensive care unit (NICU) admission, hypoglycemia, necrotizing enterocolitis, intraventricular hemorrhage, and neonatal death. Statistical analyses were performed by using SPSS software, version 26.0.ResultsThe proportion of RD in LPI was significantly lower in the treatment group than in the matched control group (10.3% vs. 23.1%, respectively), adjusted Odds Ratio [aOR] 0.29; 95% confidence interval [CI] 0.10 – 0.83 and p = 0.021. Neonatal hypoglycemia was more common in the dexamethasone group than in the matched group (25.6% vs. 12.8%, respectively; aOR, 2.59; 95% CI, 1.06 – 6.33; p = 0.037). There were no significant between-groups differences in the incidence of respiratory support, NICU admission or length of hospital stay.ConclusionsAdministration of antenatal dexamethasone to women at risk for late preterm birth could help to lower the proportion of respiratory distress in late preterm infants.

Effects of prophylactic vaginal progesterone administration on mild cervical shortening (TROPICAL study): a multicenter, double-blind, randomized trial

Vaginal progesterone reduces the preterm birth frequency among high-risk women with a cervical length ≤25 mm at midtrimester. However, the strategy may promote no substantial reduction in overall preterm birth rates, because such high-risk women are only approximately 2% of all pregnant women, which restrict the number of participants. Our purpose was to determine whether prophylactic vaginal progesterone administration can preserve cervical length and reduce preterm birth rates among women with mild cervical shortening. This multicenter, parallel-arm, double-blind, randomized, placebo-controlled trial involved vaginal progesterone administration (200 mg daily from 16 to 33 weeks of gestation) among asymptomatic women with a singleton pregnancy and a sonographic cervical length of 25 to <30 mm between 16 and 23 weeks of gestation. The primary and secondary endpoints were cervical shortening rates at 34 weeks of gestation and preterm birth rates, respectively. The trial was registered at the University Hospital Medical Information Network (UMIN000013518) in Japan. Between April 2014 and March 2018, 119 women were randomly assigned to the progesterone group (n = 59) and the placebo group (n = 60). No significant differences in the frequency of women with a cervical length ≥20 mm at 34 weeks of gestation were observed between both groups. All preterm births occurred after 34 weeks of gestation, except for one patient in the placebo group. The progesterone group had a lower rate of preterm birth before 37 weeks than the placebo group (3.4% vs. 15.0%, respectively; p < .05). Despite having no effect on preserving cervical length, prophylactic vaginal progesterone administration reduced preterm birth frequency among women with mild cervical shortening. Our results are suggesting that women with mild cervical shortening are at risk for late preterm birth and the need for expanding progesterone treatment indications to include not only high-risk but also low-risk populations.

Time interval from late preterm antenatal corticosteroid administration to delivery and the impact on neonatal outcomes

Although administration of antenatal corticosteroids has been shown to decrease neonatal respiratory morbidity when given to women at risk for late preterm birth, the time interval from antenatal corticosteroid administration to delivery that is associated with the greatest neonatal benefit remains unknown. This study aimed to evaluate whether the time interval from administration of late preterm antenatal corticosteroids to delivery is associated with a change in the likelihood of transient tachypnea of the newborn, respiratory distress syndrome, and hypoglycemia. This was a retrospective cohort study of all singleton neonates who were exposed to 1 or 2 doses of antenatal corticosteroids in the late preterm period (34+0 to 36+6 weeks' gestation) within a large healthcare system between November 2017 and March 2020. Neonates exposed to antenatal corticosteroids before 34 weeks' gestation and those with major fetal structural malformations and chromosomal disorders were excluded. Cases were stratified into the following groups based on the time interval from the first dose of antenatal corticosteroid administration to delivery: <2 days, 2 to 7 days, and >7 days. The primary outcome of transient tachypnea of the newborn was compared among the 3 groups. Secondary outcomes included respiratory distress syndrome and hypoglycemia. A multivariable logistic regression was performed to evaluate the association between the time interval and neonatal outcomes while adjusting for potential confounders. For each outcome, delivery within 2 to 7 days from the first dose of betamethasone administration was defined as the reference group. Data were presented as adjusted odds ratios with 95% confidence intervals, and statistical significance was defined as P < .05. The study cohort comprised 1248 neonates. Of those, 649 (52%) were exposed to 1 dose of antenatal corticosteroids. There were statistically significant differences in the maternal characteristics such as nulliparity, pregnancies complicated by hypertensive disorders and fetal growth restriction, gestational age at antenatal corticosteroid administration, gestational age at delivery, and mode of delivery among the 3 groups. There was a significantly increased risk for transient tachypnea of the newborn (adjusted odds ratio, 4.81; 95% confidence interval, 1.72-12.92) and respiratory distress syndrome (adjusted odds ratio, 9.86; 95% confidence interval, 1.15-84.24) associated with delivery <2 days of antenatal corticosteroid administration. The risk for hypoglycemia was highest in the delivery <2 days group (adjusted odds ratio, 3.44; 95% confidence interval, 2.10-5.63) and decreased as the time interval from antenatal corticosteroid administration to delivery increased (adjusted odds ratio, 0.32; 95% confidence interval, 0.20-0.51 for delivery >7 days). Adverse neonatal outcomes such as transient tachypnea of the newborn, respiratory distress syndrome, and hypoglycemia are more common when late preterm birth occurs <2 days after antenatal corticosteroid administration when compared with birth 2 to 7 days after administration. In addition, delivery >7 days after antenatal corticosteroid administration is associated with a decreased risk for hypoglycemia. Understanding the impact of antenatal corticosteroid timing on neonatal outcomes is essential in caring for patients at risk for late preterm birth.

958 The impact of time interval from late preterm corticosteroid administration to delivery on neonatal outcomes

While administration of antenatal corticosteroids (ACS) has been shown to decrease newborn respiratory morbidity when given to women at risk for late preterm birth (PTB), the optimal time interval from ACS to delivery remains unknown. We investigated the association of the time interval from ACS to delivery and adverse neonatal outcomes. Retrospective cohort of all newborns from singleton pregnancies that were exposed to ACS in the late preterm period (34 0/7-36 6/7 weeks) within a large health system (November 2017- March 2020). Newborns exposed to ACS prior to the late preterm period, major fetal structural malformations and confirmed chromosomal disorders were excluded. Cases were stratified based on time interval from ACS administration to delivery: <2, 2-7, and >7 days. The rates of transient tachypnea of the newborn (TTN), respiratory distress syndrome (RDS), and hypoglycemia were compared among the three groups. Multivariate logistic regression was performed to evaluate the association of time interval with neonatal outcomes, while adjusting for potential confounders. 1,248 newborns comprised the study cohort. Baseline characteristics compared among the three groups are displayed in Table 1. After adjusting for number of ACS doses (1 or 2) and gestational age at delivery, we detected an increased risk of TTN associated with delivery <2 days (aOR 3.80, 95% CI 1.42-10.18) and >7 days (aOR 3.39, 95% CI 1.12-10.27) of ACS administration (Table 2). The risk of hypoglycemia was highest in the delivery <2 days group (aOR 3.3, 95% CI 2.01-5.41) and decreased as time interval from ACS to delivery increased (Table 2). Adverse neonatal outcomes such as TTN and hypoglycemia are more common when late PTB occurs <2 days after ACS administration. Moreover, late PTB >7 days after ACS administration is associated with an increased risk of TTN, but a decreased risk of hypoglycemia. Understanding the impact of ACS timing on neonatal outcomes is essential in caring for patients at risk for late PTB.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Maternal pre-pregnancy underweight as a risk factor for the offspring: Survey of Neonates in Pomerania.

The aim was to investigate socio-economic risk factors for maternal underweight before pregnancy and then associations of underweight with neonatal outcomes. Data of 3401 mother-child dyads from the population-based birth cohort Survey of Neonates in Pomerania (SNiP) were analysed. Bivariate analysis showed that underweighted mothers were younger, smoked more often, had a lower equivalent income and lower socio-economic status (employment status and/or educational level) compared to women with normal weight. The final prediction model revealed that only younger maternal age (OR=0.93; 95%-CI=0.90-0.97) and maternal smoking during pregnancy (OR=2.52; 95%-CI=1.74-3.66) were associated with underweight. Compared to women with normal pre-pregnancy BMI, underweight women had an increased chance of premature labour (OR=1.73; 95% CI: 1.29-2.31) and a reduced placental weight. The offspring of underweight women had an increased risk of late preterm birth (OR=1.82; 95% CI: 1.21-2.74) and birthweight<2500g (OR=1.91; 95% CI: 1.23-2.95). Smoking during pregnancy and a younger age were identified as risk factors for maternal pre-pregnancy underweight which then was associated with late preterm birth and low birthweight.

Factors Associated with Formula Feeding among Late Preterm Neonates.

Late preterm births (delivery at 34-36 weeks) account for nearly three quarters of the preterm births and among them there is a knowledge gap about an important aspect of infant care: breast versus formula feeding. The aim of this study was to assess factors associated with formula feeding in late preterm neonates. Secondary analysis of a multicenter randomized trial of antenatal corticosteroids for women at risk for late preterm birth. All women with a singleton pregnancy who delivered at 340/7 to 366/7 weeks were included. Women with no information on neonatal feeding or known fetal anomalies were excluded. The outcome evaluated was the type of neonatal feeding during hospital stay. Maternal and neonatal characteristics were compared among women who initiated breast versus formula feeding. Adjusted relative risks (aRRs) for formula feeding with 95% confidence intervals (CIs) were calculated. Of the 2,831 women in the parent trial, 2,329 (82%) women met inclusion criteria and among them, 696 (30%) were formula feeding. After multivariable regression, the following characteristics were associated with an increased risk of formula feeding: maternal age < 20 years (aRR: 1.47, 95% CI: 1.20-1.80) or ≥35 years (aRR: 1.19, 95% CI: 1.02-1.40), never married status (aRR: 1.39, 95% CI: 1.20-1.60), government-assisted insurance (aRR: 1.41, 95% CI: 1.16-1.70), chronic hypertension (aRR: 1.19, 95% CI: 1.01-1.40), smoking (aRR: 1.51, 95% CI: 1.31-1.74), cesarean delivery (aRR: 1.16, 95% CI: 1.03-1.32), and admission to neonatal intensive care unit (aRR: 1.31, 95% CI: 1.16-1.48). Hispanic ethnicity (aRR: 0.78, 95% CI: 0.64-0.94), education >12 years (aRR: 0.81, 95% CI 0.69-0.96), and nulliparity (aRR 0.71, 95% CI: 0.62-0.82) were associated with a reduced risk for formula feeding. In this geographically diverse cohort of high-risk deliveries, 3 out 10 late preterm newborns were formula fed. Smoking cessation was a modifiable risk factor that may diminish the rate of formula feeding among late preterm births. · Three of ten late preterm do not benefit from breastfeeding.. · Demographic characteristics are associated with type of feeding.. · Smoking cessation may improve the rate of breastfeeding..

158: The association of delivery indication with neonatal outcomes in the late preterm period

Whether the indication for delivery in the late preterm period is associated with neonatal outcomes is poorly understood. We therefore took advantage of a large, carefully characterized cohort of women at high risk of late preterm birth to evaluate this issue. This is a secondary analysis of a multicenter, placebo controlled trial in which women with singleton pregnancies at risk for delivery at 34 0/7 - 36 5/7 weeks’ gestation were randomized to a single course of antenatal corticosteroids (betamethasone) or placebo. Women were eligible if they were in spontaneous preterm labor (PTL); had preterm prelabor rupture of membranes (PPROM); or were undergoing indicated preterm delivery (iPTD). The primary outcome was a composite of respiratory treatment within 72 hours of delivery, stillbirth, or neonatal death. Other outcomes included major respiratory morbidity; use of continuous positive airway pressure or high flow nasal cannula; a composite of respiratory distress syndrome, transient tachypnea of the newborn, and apnea; newborn intensive care unit admission; and feeding problems. Odds ratios (OR) were calculated for outcomes by indication and adjusted (aOR) for gestational age, birth weight, infant sex, delivery route, major malformations, race/ethnicity, and treatment group. There were 2,831 participants: 792 (28.0%) PTL, 620 (21.9%) PPROM, and 1,419 (50.1%) iPTD. The primary outcome occurred in 232 (16.4%) infants born after iPTD versus 58 (7.3%) infants born after PTL (aOR 1.71, 95% CI 1.21-2.43), and versus 77 (12.4%) infants born after PPROM (aOR 2.01, 95% CI 1.45 – 2.79). Compared to PTL, all neonatal complications except feeding problems occurred significantly more frequently in the iPTD group. Compared to PPROM, iPTD had significantly more neonatal complications across all measures except NICU admission. Outcomes were similar between PPROM and PTL (Table 1). Among late preterm infants, iPTD was associated with greater neonatal morbidity and respiratory complications compared with PTL or PPROM despite the administration of antenatal corticosteroids.

Neonatal morbidity in late preterm small for gestational age neonates

Introduction To compare neonatal respiratory morbidity among small for gestational age (SGA; birth weight less than 10th percentile for gestational age) versus appropriate for gestational age (AGA; BW at 10–90th percentile) neonates born in the late preterm period. Methods A secondary analysis of a multicenter randomized trial of antenatal corticosteroids for women at risk for late preterm birth. Singleton, nonanomalous, AGA or SGA births that delivered at 34–36 weeks were included. Women were excluded if they delivered after 37 weeks or had a large for gestational age baby (LGA; weight over 90th for gestational age). The primary outcome was a composite of any of the following: respiratory support by 72 h (continuous positive airway pressure or high flow nasal cannula ≥2 h, oxygen with a fraction of inspired oxygen of ≥30% for ≥4 h, extra corporeal membrane oxygenation or mechanical ventilation) or neonatal death. The secondary outcomes included several neonatal and maternal morbidities. Multivariable Poisson regression models were used to examine the association between neonatal weight and outcomes (using adjusted relative risk [aRR] and 95% confidence intervals [CI]). Results Of the 2831 women in the parent trial, 2315 (82%) women met inclusion criteria; among them, 426 (18%) of the neonates were SGA. There was no significant difference in the risk of the primary outcome between SGA and AGA (13.1 versus 15.1%, aRR 0.85, 95% CI 0.66–1.10). SGA, however, was associated with an increased risk for neonatal intensive care unit admission (68 versus 45%, aRR 1.60, 95% CI 1.47–1.74), hypothermia (12.2 versus 8.8%, aRR 1.36, 95% CI 1.01–1.83), feeding problems (47.2 versus 36.9%, aRR 1.24, 95% CI 1.07–1.45) and a decreased risk of neonatal hyperbilirubinemia (7.5 versus 12.7%, aRR 0.59, 95% CI 0.41–0.84), when compared to AGA. Conclusion In this cohort of late preterm birth, there was no significant difference in the rate of composite respiratory morbidity between SGA and AGA newborns.

Pregnancy outcomes in women with primary systemic vasculitis: a retrospective study

Background/aims Pregnancies in women with systemic vasculitis constitute high-risk pregnancies, and outcomes vary based on the size of the affected blood vessels. Currently, there is limited data describing pregnancy outcomes in these women. The aim of this paper is to evaluate pregnancy outcomes in women with large, medium, or small vessel vasculitis to aid preconceptional counseling and inform antepartum and intrapartum care. Methods We included all women with large-, medium-, or small-vessel vasculitis and documented pregnancies attending high-risk pregnancy clinics at Mount Sinai Hospital, Toronto, Canada between 2001 and 2016. Pregnancy characteristics and outcomes were reported as proportions. Maternal, fetal/neonatal, and obstetric outcomes, stratified by type of vasculitis, were the main outcomes measured. Results We identified 60 pregnancies in 50 women with systemic vasculitis. These included large-vessel (n = 10), medium-vessel (n = 5), small-vessel [n = 30, of which 16 were AntiNeutrophil Cytoplasmic Autoantibody (ANCA)-associated and 14 were immune-complex mediated], central nervous system (n = 3), and retinal (n = 2). Although vasculitis flares occurred with large-vessel (3/12), small-vessel (13/36), and retinal (2/3) vasculitis, only one was severe and involved hemoptysis requiring blood transfusion in a woman with ANCA-associated vasculitis. Preeclampsia complicated two pregnancies each with large- (25%) and small- (6%) vessel vasculitis. Intrauterine growth restriction (IUGR) only occurred with small-vessel vasculitis (10, 29.4%). Although seven (26.4%) viable pregnancies resulted in preterm birth, the mean gestational age was over 35 weeks. Conclusion Although women with systemic vasculitis can have successful pregnancies, they are at increased risk for late preterm birth. In addition, those with small-vessel vasculitis are at increased risk for IUGR and vasculitis flares.

Sex-Specific Differences in Late Preterm Neonatal Outcomes.

To estimate sex-specific differences in late preterm outcomes and evaluate whether betamethasone modifies this association. We conducted a secondary analysis of a multicenter trial of women at risk for late preterm birth randomized to receive betamethasone or placebo. We included women who delivered at 34 to 37 weeks and excluded major fetal anomalies. The primary outcome was severe neonatal morbidity (mechanical ventilation, respiratory distress syndrome, bronchopulmonary dysplasia, sepsis, necrotizing enterocolitis, and intraventricular hemorrhage). Maternal characteristics were compared using chi-square test, t-test, or Mann-Whitney U-test. Multivariable logistic regression estimated the association between sex and morbidity, and likelihood ratio testing assessed for effect modification by betamethasone. Of 2,831 women in the primary trial, 2,331 met the inclusion criteria: 1,236 delivered males and 1,095 delivered females. Betamethasone modified the association between sex and severe morbidity (p = 0.047). Among those who received betamethasone, male sex was associated with higher odds of severe morbidity (adjusted odds ratio: 1.95, 95% confidence interval: 1.25-3.05), compared with female sex. Among those who did not receive betamethasone, there was no significant association between sex and morbidity. Male sex is a risk factor for adverse late preterm outcomes, including severe neonatal morbidity after betamethasone receipt.

Effects of antenatal corticosteroids in twin neonates with late preterm birth (ACTWIN [Antenatal Corticosteroids in TWIN late preterm neonates] trial): study protocol for a randomized controlled trial

BackgroundAntenatal corticosteroids have been proven to prevent adverse outcomes including respiratory morbidities in preterm neonates before 34 weeks of gestation. Recently, it has been suggested that antenatal corticosteroids may also be effective in singleton late preterm pregnancies, and guidelines recommend the use of corticosteroids in singleton pregnant women who are at risk for late preterm birth. On the contrary, there is a paucity of information regarding the effectiveness of corticosteroids in twin neonates with late preterm birth. This study aims to determine the effectiveness of antenatal corticosteroids in late preterm twin neonates.MethodsIn this multicentre randomized controlled trial, women who are at risk for late preterm birth will be enrolled at 34 0/7 to 36 5/7 weeks of gestation. The participants will be randomly assigned to receive antenatal corticosteroids (betamethasone 12 mg, 3 mL intramuscularly [IM]) or placebo (normal saline 3 mL IM). The perinatal outcomes will be compared between the two groups of cases. The primary outcome is severe respiratory complications (the use of continuous positive airway pressure or high-flow nasal cannula for at least 12 h, supplemental oxygen administration with a fraction of oxygen 0.3 or more for at least 24 h, mechanical ventilation, or extracorporeal membranes oxygenation) or perinatal death within the first 72 h of delivery. The secondary outcomes are neonatal mortality and/or other neonatal morbidities.DiscussionThis study will be the first randomized controlled trial that evaluates the effectiveness of antenatal corticosteroids in late preterm twin neonates.Trial registrationNCT03547791(ClinicalTrials.gov), first submitted date: March 29, 2018, first posted date: June 6, 2018 (retrospectively registered).

464: Time interval from betamethasone to delivery among women at risk for late preterm delivery

Beneficial effects of betamethasone in the late preterm period are known (Gyamfi-Bannerman, C, et al NEJM 2016). The optimal time interval between betamethasone and delivery, however, is uncertain. Among women at risk of late preterm delivery, we sought to determine whether time interval (TI) between betamethasone and delivery is associated with neonatal adverse respiratory outcomes. This is a secondary analysis of a multicenter randomized trial to determine the effects of betamethasone in women at risk for late preterm delivery. The inclusion criteria for our analysis were singletons with no major anomaly, receiving betamethasone, with calculable TI between administration of last betamethasone dose and delivery. TI categories were: 1) ≤ 48 hours; 2) > 48 and ≤ 168 hours, and; 3) > 168 hours (7 days). Primary outcome was neonatal respiratory outcomes among the 3 TI groups. Primary and secondary outcomes are defined in the tables. Multivariable Poisson regression models with robust error variance were used to determine the association between TI and neonatal outcomes, while adjusting for confounders. Adjusted relative risk (aRR) with 95% confidence intervals (CI) were calculated, using TI > 48 and ≤ 168 hours as the referent group. Of the 2,831 women in the parent trial, 1,414 (50.7%) met our inclusion criteria. While 68.5% delivered in ≤ 48 hours, 15.3% were born > 48 and ≤ 168 hours and 16.2% at > 168 hrs. Factors significantly different among the three groups include: nulliparity, pre-pregnancy BMI, hypertensive disease, premature preterm rupture of membranes, number of betamethasone doses (1 versus 2), preterm delivery (gestational age < 37 weeks), labor type, and route of delivery. Among women who received betamethasone, the primary outcome was significantly less if delivery occurred > 168 hours, compared to > 48 and ≤ 168 hrs. Severe respiratory complications were also significantly lower if delivery occurred > 168 hours, compared to > 48 and ≤ 168 hours. (Table) Even when adjusted for rate of preterm birth, among women at risk for late preterm birth, the lowest rate of neonatal respiratory complication is when delivery occurred beyond 168 hrs (7 days).

Does external cephalic version for breech presentation performed prior to an estimated gestational age of 37 weeks offer any benefits or pose any risks compared with external cephalic version performed at term?

EVIDENCE-BASED ANSWER Compared with term external cephalic version, preterm (<37 weeks' gestation) external cephalic version decreases the rate of noncephalic presentation at birth by 19% and the rate of vaginal breech birth by 56%, but increases the risk of late preterm birth by 50% (SOR: A, systematic review of RCTs). The 2016 American College of Obstetrician and Gynecologists guidelines for the management of external cephalic version recommend offering the procedure near term. In comparison, the 2010 guidelines from the Royal College of Obstetricians and Gynaecologists recommend external cephalic version at 36 weeks for nulligravidas and 37 weeks for multigravidas (SOR: C, systematic guidelines).

Late preterm birth and previous cesarean section: a population-based cohort study

Background: Late preterm birth (LPB) is increasingly common and associated with higher morbidity and mortality than term birth. Yet, little is known about the influence of previous cesarean section (PCS) and the occurrence of LPB in subsequent pregnancies. We aim to evaluate this association along with the potential mediation by cesarean sections in the current pregnancy.Methods: We use population-based birth registry data (2005–2012) to establish a cohort of live born singleton infants born between 34 and 41 gestational weeks to multiparous mothers. PCS was the primary exposure, LPB (34–36 weeks) was the primary outcome, and an unplanned or emergency cesarean section in the current pregnancy was the potential mediator. Associations were quantified using propensity weighted multivariable Poisson regression, and mediating associations were explored using the Baron-Kenny approach.Results: The cohort included 481,531 births, 21,893 (4.5%) were LPB, and 119,983 (24.9%) were predated by at least one PCS. Among mothers with at least one PCS, 6307 (5.26%) were LPB. There was increased risk of LPB among women with at least one PCS (adjusted Relative Risk (aRR): 1.20 (95%CI [1.16, 1.23]). Unplanned or emergency cesarean section in the current pregnancy was identified as a strong mediator to this relationship (mediation ratio = 97%).Conclusions: PCS was associated with higher risk of LPB in subsequent pregnancies. This may be due to an increased risk of subsequent unplanned or emergency preterm cesarean sections. Efforts to minimize index cesarean sections may reduce the risk of LPB in subsequent pregnancies.