CORTICOTROPIN-RELEASING HORMONE AND PITUITARY-ADRENAL HORMONES IN PREGNANCIES COMPLICATED BY CHRONIC HYPERTENSION

OBJECTIVE: We hypothesized that maternal plasma corticotropin-releasin g hormone levels are elevated in chronic hypertension and that elevati ons modulate maternal and fetal pituitary-adrenal function. STUDY DESI GN: Venous blood samples and 24-hour urine specimens were obtained in normal and hypertensive pregnancies at 21 to 40 weeks of gestation. Co rticotropin-releasing hormone, corticotropin, cortisol, dehydroepiandr osterone sulfate, and total estriol levels were measured by radioimmun oassay. Mean hormone levels were compared by unpaired t test or two-wa y analysis of variance. RESULTS: Plasma corticotropin-releasing hormon e levels were elevated early in hypertensive pregnancies but did not i ncrease after 36 weeks. Levels of pituitary and adrenal hormones were not different in normal and hypertensive women. However, maternal plas ma estriol levels were lower in hypertensive pregnancies compared with normal pregnancies. CONCLUSIONS: Fetal 16-hydroxy dehydroepiandroster one sulfate, the major precursor to placental estriol production, has been reported to be lower than normal in hypertensive pregnancies, pos sibly explaining the decreased plasma estriol levels reported here. Ea rly stimulation of placental corticotropin-releasing hormone productio n or secretion may be related to accelerated maturation of placental e ndocrine function in pregnancies complicated by chronic hypertension.