PLACENTAL CORTICOTROPIN-RELEASING HORMONE AND THE HYPERCORTISOLISM OFPREGNANCY

OBJECTIVE: Our purpose was to clarify whether placental corticotropin- releasing hormone regulates pituitary-adrenal function in human pregna ncy. STUDY DESIGN: We examined the relationship between maternal plasm a corticotropin-releasing hormone concentrations and levels of pituita ry-adrenal hormones at 5-week intervals in 21 uncomplicated term pregn ancies. RESULTS: Maternal plasma corticotropin-releasing hormone conce ntrations rose significantly from 115 +/- 45 pg/ml at 11 to 15 weeks t o 4346 +/- 754 pg/ml at 36 to 40 weeks (p < 0.001). Afternoon plasma c orticotropin concentrations also rose significantly from 8.8 +/- 2.8 p g/ml to 18 +/- 2.6 pg/ml (p < 0.005). Urinary free cortisol concentrat ions rose from 54.8 +/- 7.3 mu g per 24-hours to 111 +/- 8.7 mu g per 24 hours (p < 0.005). Maternal dehydroepiandrosterone sulfate levels f ell from 102 +/- 14 mu g/dl to 63.8 +/- 7.1 mu g/dl (p < 0.005). Mater nal plasma corticotropin-releasing hormone was significantly correlate d with afternoon plasma corticotropin concentrations (r = 0.6, p < 0.0 001) and with urinary free cortisol concentrations (r = 0.04, p < 0.01 ). CONCLUSIONS: Similar modest elevations of corticotropin and cortiso l, as occur in pregnancy, have been reported in vitro and in vivo stud ies of long-term administration of corticotropin-releasing hormone. Ou r findings support the concept that placental corticotropin-releasing hormone modulates pituitary-adrenal function in pregnancy.