Determinants of meconium-stained amniotic fluid in term pregnancies.

This study examines ethnic variations in meconium-stained amniotic fluid in term pregnancies, taking into account the role of gestational age, maternal sociodemographic characteristics, and medical risk factors. The study population included black and white singleton live births (N = 14,419) between 37 and 42 weeks' gestation, delivered vaginally at the Medical University of South Carolina from 1982 through 1990. Chi-square and logistic regression analysis were used to examine the association between the independent variables and meconium-stained amniotic fluid (MSAF). An increased risk of MSAF was found for advancing gestational age, indicators of fetal stress, fewer than five prenatal care visits, and > 15 hours labor. After controlling for demographic and clinical characteristics, the risk of MSAF in black patients was approximately 1.5 times that of white patients. The higher proportion of MSAF in blacks could not be explained with obvious risk factors.