Meconium-stained Amniotic Fluid—Perinatal Outcome and Obstetrical Management in a Low-Risk Suburban Population

Abstract

Although the presence of meconium-stained amniotic fluid (MSAF) has in the past been viewed as a significant indicator of adverse fetal status, the great majority of infants born with MSAF are not impaired in the short or the long term. Although some studies have shown a link between MSAF, low Apgar scores, and decreased arterial cord blood pH values, many of these studies were performed over 10 years ago and included women of very specific ethnic and socioeconomic populations. Thus, their relevance to the current practice of obstetrics is unclear. The present retrospective cohort study included 11,226 deliveries taking place in the years 1998-2003 in a typical European suburban population. Each of 1123 women with MSAF-representing 10% of the study population-had a term singleton pregnancy with cephalic presentation and underwent a trial of vaginal delivery. Control women were the next to give birth without MSAF. Severe maternal disease, preeclampsia, and fetal malformations precluded participation in the study. There were no differences in Apgar scores in the MSAF and non-MSAF groups, and in both groups the mean arterial pH was 7.26. The respective rates of a 5-minute Apgar score below 6 were 0.9% and 0.4%. Obstetrical interventions were more frequent in the MSAF group. Cesarean delivery was carried out in 17.4% of the MSA group and 9.6% of the non-MSAF group, and operative vaginal delivery in 13.9% and 6.2%, respectively. Infants in the MSAF group were heavier, but to a large degree this reflected more advanced gestational age. Multivariate analysis, controlling for parity, gestational age, infant weight, maternal age, and the use of epidural analgesia and oxytocin, indicated that obstetrical interventions such as cesarean section had a significant protective effect regardless of whether or not MSAF was present. The presence of MSAF had little effect on the newborn infant during the immediate postpartum period in this low-risk population. Nevertheless, it does influence obstetrical management, possibly because of more difficult labors or a lower threshold for obstetrical intervention.