Neonatal Outcomes After Demonstrated Fetal Lung Maturity Before 39 Weeks of Gestation

Abstract

Objective To compare outcomes among neonates delivered after documentation of fetal lung maturity prior to 39 weeks and those delivered at 39 or 40 weeks. Methods This was a retrospective cohort study of women with singleton pregnancy delivered at 36 0/7 to 38 6/7 weeks after positive fetal lung maturity testing (based on amniotic fluid lecithin to sphingomeylin ratio) or at 39 0/7 to 40 6/7 weeks (without maturity testing) at our center from 1999-2008. Women with major congenital anomalies, cord prolapse, non-reassuring antepartum testing, placental abruption, or oligohydramnios were excluded. A primary composite neonatal outcome included death, adverse respiratory outcomes, hypoglycemia, treated hyperbilirubinemia, generalized seizures, necrotizing enterocolitis, hypoxic ischemic encephalopathy, periventricular leukomalacia, and suspected or proven sepsis. Results There were 459 neonates delivered at 36-38 weeks and 13,339 delivered at 39-40 weeks; mean birth weight was 3107±548 and 3362±439 grams, respectively. The risk of the composite adverse neonatal outcome was 6.1% for the 36-38 week group compared to 2.5% for the 39-40 week group; RR 2.4; 1.7-3.5. After multivariable adjustment, early delivery remained significantly associated with an increased risk of the composite outcome (adjusted OR 1.7; 1.1-2.6) as well as several individual outcomes, including respiratory distress syndrome (7.6; 2.2-26.6), treated hyperbilirubinemia (11.2; 3.6-34) and hypoglycemia (5.8; 2.4-14.3). Conclusions Neonates delivered at 36-38 weeks after confirmed fetal lung maturity are at higher risk of adverse outcomes than those delivered at 39-40 weeks.

The influence of pre‐eclampsia on fetal lung maturity

“…Near-term pregnancies are commonly thought to be safe with regard to neonatal outcome but there have been reports that near-term deliveries, even without other complications than prematurity, are associated with more neonatal complications than are term deliveries [14][15][16][17]. Delayed FLM associated with pre-eclampsia in the present study was indicated by significantly lower median LBCs in the combined group of preeclamptic and IUGR pregnancies than in control pregnancies and those affected by IUGR.…”

What we have learned about scheduling elective repeat cesarean delivery at term

“…Both studies showed significantly higher risks of adverse outcomes with delivery prior to 39 weeks. 21,22 Does labor prior to elective repeat cesarean delivery pose maternal and fetal risks?…”

Evaluation of Respiratory Problems According to Week of Delivery: A Comparative Analysis in Infants of Gestational Age 37 Weeks

“…The present study demonstrated 16.3% of NICU admission rates for early-term infants which were quite similar to previous research reaching up to 17.8% (3,13). This period has a tendency to develop RDS compared to later gestations (15)(16)(17). Morrison et al reported the rates of respiratory morbidity by CS-induced iatrogenic prematurity as 73.8/1000 at 37th week of GA, 42.3/1000 at 38th GA and 17.8/1000 at 39th GA which were inversely proportional with gestational weeks (18).…”