CIRCULATING MATERNAL CORTICOTROPIN-RELEASING HORMONE AND GONADOTROPIN-RELEASING-HORMONE IN NORMAL AND ABNORMAL PREGNANCIES

OBJECTIVE: Corticotropin-releasing hormone and gonadotropin-releasing hormone are produced by the human placenta and have been measured in t he maternal circulation during pregnancy, Our objective was to determi ne concentrations of these substances in maternal plasma throughout no rmal pregnancies and in early pregnancy loss. STUDY DESIGN: Fifty-one pregnant women were followed up prospectively and plasma samples were drawn at 8, 10, 12, 14, 16, 28, and 36 weeks' gestation and during lab or. Specific and sensitive radioimmunoassays were used to determine co rticotropin-releasing hormone and gonadotropin-releasing hormone conce ntrations in these samples. RESULTS: Blood samples were drawn at all t ime points and outcome data were available from 33 women who completed their pregnancies at term without complications. In this normal group circulating corticotropin-releasing hormone concentrations increased from low or undetectable concentrations at 8 weeks (less than or equal to 23.2 +/- 1.3 pg/ml, mean +/- SEM) to measurable values at 16 weeks (34.3 +/- 2.2 pg/ml). Thereafter there was a significant increase to 1294 +/- 113 pg/ml in labor. Gonadotropin-releasing hormone demonstrat ed a trimodal distribution, increasing significantly from 8 to 14 week s, decreasing at 16 weeks, and increasing again by term. The ratio of corticotropin-releasing hormone to gonadotropin-releasing hormone in t he normal group demonstrated a 30-fold increase from 8 weeks to term. In eight cases of early pregnancy loss corticotropin-releasing hormone and gonadotropin-releasing hormone concentrations were not significan tly different from those of the normal group in early pregnancy. In tw o cases of premature delivery gonadotropin-releasing hormone concentra tions and ratios were within the normal range; corticotropin-releasing hormone levels were normal in both cases of premature delivery. CONCL USION: In this study we determined maternal concentrations of corticot ropin-releasing hormone and gonadotropin-releasing hormone in normal p regnancies and in labor at term. Neither maternal concentrations of co rticotropin-releasing hormone nor gonadotropin-re[easing hormone were useful in identifying pregnant women at risk for early pregnancy loss.