Amniocentesis for threatened preterm labor with intact membranes and the impact on adverse outcome in infants born at 22 to 28 weeks of gestation

•Amniocentesis is beneficial for preterm labor to improve infant's long-term outcome.•Amniotic fluid Gram staining, glucose, and white blood cell are useful for diagnosis.•Subclinical intra-amniotic infection is present at least in 10% of women having preterm labor and intact membranes.

BackgroundIt remains unclear whether performing amniocentesis to detect intra-amniotic infection is useful for improving neonatal outcomes.AimsTo determine the efficacy of amniocentesis on the neonatal outcomes in women exhibiting threatened preterm labor and intact membranes.Study designRetrospective cohort studySubjectsA total of 174 women with threatened preterm labor and intact membranes at 22 to 33 weeks of gestation. Women with obvious clinical chorioamnionitis, multifetal pregnancy and/or major anomalies were excluded.Outcome MeasuresNeonatal short- and long-term outcomesResultsSixty-seven women underwent amniocentesis (Tap group), while the remaining 107 did not. The prevalence of a positive Gram stain or a positive culture result was 10% in the Tap group. The overall outcomes were not statistically different between the two groups, with the exception of borderline significance (p = 0.052) in long-term outcomes, favoring the Tap group. We performed a subgroup analysis focusing on infants born at 22–28 weeks of gestation. Consequently, the Tap group had better neonatal outcomes than the no-Tap group with respect to both short-term (OR 0.19, 95%CI 0.07–0.55) and long-term (OR 0.15, 0.05–0.46) outcomes. A multivariate analysis revealed that after adjusting confounding factors, the gestational age at delivery (OR 0.4, 0.3–0.7) and amniocentesis (OR 0.1, 0.02–0.3) remained significantly different.ConclusionsAmniocentesis is useful for improving neonatal outcomes in infants born at 22–28 weeks of gestation to women exhibiting preterm labor and intact membranes.