Meconium staining of amniotic fluid at midtrimester amniocentesis.

Meconium-stained fluid was found in six of the first 234 amniocenteses performed at the University of Washington Prenatal Diagnosis Center. The taps were done between 16 and 20 weeks from the last menstrual period. Although in each case there was a factor that could have produced fetal distress, in no instance did intrauterine demise occur. All the pregnancies have terminated in the births of healthy children. Therefore, we believe that meconium staining of midtrimester amniotic fluid may in fact reflect a transient episode of fetal compromise but that the finding cannot be used to prognosticate either impending fetal death or the presence of congenital malformations in the newborn.