Effects of exposure to tobacco smoke in pregnancies complicted by oligohydramnios and premature rupture of the membranes. II. Activity of brush border enzymes in human amniotic fluid.

The aim of the present study was to assess the activity of membrane enzymes: alanine aminopeptidase (AAP), gamma-glutamyltransferase (GGT) and trehalase in amniotic fluid of women who smoke cigarettes during pregnancy complicated by idiopathic oligohydramnios or premature rupture of the membranes (PROM). The enzyme activity was measured between 22 and 31 (group A) and between 32 and 39 (group B) weeks of gestation. In the women of group A with idiopathic oligohydramnios, AAP activity was five times higher than in PROM women. AAP activity was declining with the progression of gestation, and in the B group women with oligohydramnios, it was over eight times lower than in group A. A threefold increase in GGT activity was found in women of group A with oligohydramnios as compared to women of group A with PROM. No statistically significant differences in trehalase activity were found in amniotic fluid of women with oligohydramnios and PROM, AAP, GGT and trehalase activity in women with idiopathic oligohydramnios correlated with the cadmium ion concentration, and AAP and GGT activity with the lead ion concentration in amniotic fluid which confirms toxical properties of these heavy metals present in cigarette smoke. It has already been confirmed that measurements of the brush border enzyme activity in amniotic fluid are very useful in prenatal diagnosis and detection of the placenta disorders.