Serum allopregnanolone levels in pregnant women: Changes during pregnancy,at delivery, and in hypertensive patients

Allopregnanolone is a neuroactive steroid measurable in peripheral circulat ion. The aim of the present study was to investigate the presence and the p ossible changes in serum allopregnanolone and progesterone levels in pregna nt women during gestation, at delivery, and in patients with chronic hypert ension, with or without superimposed preeclampsia. We also evaluated allopr egnanolone in cord blood. Three groups of pregnant women were studied: 1) h ealthy controls followed longitudinally throughout gestation (n = 14); 2) a t vaginal or cesarean delivery (n = 66); and 3) with chronic hypertension ( n = 12), with (n = 7) or without (n = 5) superimposed preeclampsia. Allopre gnanolone and progesterone levels were measured in maternal and cord serum by RIA. In healthy pregnant women, serum allopregnanolone and progesterone levels progressively increased throughout gestation. Whereas no changes wer e found at vaginal delivery, serum allopregnanolone and progesterone levels were significantly lower at delivery by emergency cesarean section (P < 0. 01). Umbilical cord serum allopregnanolone and progesterone levels in emerg ency cesarean were significantly lower than those found at vaginal delivery (P < 0.01). Patients with chronic hyper tension, with or without superimpo sed severe preeclampsia, showed serum allopregnanolone levels significantly higher than those of healthy women at the same gestational age (P < 0.01). In conclusion, maternal serum allopregnanolone levels increased during nor mal gestation were lower in women who underwent emergency cesarean and high er in patients with chronic hypertension, with or without preeclampsia. Bec ause allopregnanolone is active on the central nervous system and in the co ntrol of systemic blood pressure, an involvement of this neurosteroid in th e adaptive processes induced by pregnancy is suggested.