Determination of bile acid concentration in human amniotic fluid for prenatal diagnosis of intestinal obstruction.

Bile acid concentration was measured in amniotic fluid obtained for standard indications from 11 healthy pregnant women without polyhydramnios (28 to 42 weeks of gestation) and from 9 patients with polyhydramnios (28 to 38 weeks of gestation). Two of the latter women delivered infants with intestinal obstruction distal to the papilla of Vater, a condition that causes regurgitation of bile into the amniotic fluid. In the women without polyhydramios, the total bile acid concentration ranged from 1.4 to 2.4 micronmol/liter. In the seven patients with polyhydramnios not associated with fetal intestinal obstruction, the bile acid concentration in amniotic fluid was not significantly different (0.9 to 1.9 micronmol/liter). By contrast, the bile acid concentration in amniotic fluid specimens from the two patients with polyhydramnios who gave birth to children with intestinal obstruction was considerably elevated (30.3 to 83.1 micronmol/liter). These findings suggest that determination of bile acid concentration in amniotic fluid permits prenatal diagnosis of intestinal obstruction distal to the papilla of Vater.