ABNORMAL CONCENTRATION OF MATERNAL SERUM ACTIVIN-A IN GESTATIONAL DISEASES

Serum plasma activin-A is measurable in the maternal circulation of he althy pregnant women, increases in specimens collected during the thir d trimester of gestation, and is highest at parturition. Hormone abnor malities are known to be associated with preterm labor or diabetes in pregnancy. Therefore, in the present study serum activin-A levels in n ormal controls were compared to those in pregnant women with preterm l abor or gestational diabetes. In some cases, values were obtained befo re and after insulin therapy. In other controls and patients with pret erm labor, the activin-A concentration in cord serum was also studied. A newly developed two-site immunotest was used to determine activin-A levels. Subjects included normal controls (n = 7), who were sampled t hroughout gestation every 5 weeks; pregnant women at term (38-40 weeks ) not in labor (n = 22); pregnant women at term in spontaneous labor ( <3.0 cm dilated; n = 42); women in preterm labor (25-35 weeks; n = 38) ; and women with gestational diabetes (20-39 weeks; n = 9). In control women, serum activin-A levels increased from 4.8 +/- 5.5 mu g/L (mean +/- SD) at 20 weeks to 25.4 +/- 27.8 mu g/L at 40 weeks (P < 0.01), a nd values correlated with gestational age. Pregnant women in preterm l abor had serum activin-A concentrations (89.04 +/- 173.31 mu g/L) high er than those in normal controls (P < 0.01), and no significant correl ation to gestational age was found in this group of pregnant women. He althy women in labor showed serum activin-A concentrations higher than those in women at term but not in labor (P < 0.01). Diabetic patients had serum activin-A concentrations (52.39 +/- 23.32 mu g/L) significa ntly higher than those in normal controls. In these patients, maternal serum activin-A concentrations significantly decreased to the range i n healthy controls at the same gestational age after insulin therapy ( 9.48 +/- 3.82 mu g/L). The present study shows that preterm labor is a ssociated with increased concentrations of activin-A in the maternal c irculation and cord serum. Hypersecretion of activin-A is also shown i n same patients with gestation diabetes; this reverts to normal after insulin treatment.