New onset of meconium during labor versus primary meconium-stained amniotic fluid – is there a difference in pregnancy outcome?

Abstract

Objective: To compare pregnancy outcome between deliveries complicated by new onset of meconium during labor following prior evidence of clear amniotic fluid and labors in which meconium was present to begin with.

Methods: A retrospective cohort study of all singleton term (≥37 + 0 weeks) deliveries complicated by intrapartum meconium-stained amniotic fluid in a tertiary referral medical center during the year 2012. Outcome was compared between deliveries with new onset of meconium during labor following prior evidence of clear amniotic fluid (secondary meconium group) and those in which meconium was already evident at the time of membranes rupture (primary meconium group).

Results: Of the 9167 deliveries during the study period, 694 were eligible for the study group. Of these, 537 were complicated by primary meconium and 157 by secondary meconium. Only secondary meconium, but not primary meconium, was independently associated with an increased risk of operative vaginal delivery (OVD) and adverse neonatal outcome. Pregnancies complicated by secondary meconium were independently associated with a higher rate of OVD (28.0% versus 11.4%, p < 0.001), POP position of the fetal head (6.4% versus 2.6%, p = 0.02), and adverse neonatal outcome (17.2% versus 8.9%, p = 0.003).

Conclusion: Secondary meconium is associated with a higher rate of adverse obstetrical and neonatal outcome compared with primary meconium.

• Cesarean section
• delivery
• meconium
• pregnancy