CORTICOTROPIN-RELEASING-HORMONE LEVELS IN PREGNANCY-INDUCED HYPERTENSION

High levels of corticotropin-releasing hormone (CRH) circulate in the plasma of pregnant women especially during the third trimester and eve n higher levels have been reported in abnormal pregnancies of various etiologies. One of these etiologies is pregnancy-induced hypertension (PIH). Objective: To measure CRH blood levels with a sensitive method in a large number of pregnant women with PIH, starting from very early stages of gestation, and to compare them with those in normal control s. Study design: Venous blood was withdrawn from, (a) 10 healthy women aged 20-35 years, (b) 62 pregnant women with PIH (109 samples), mean age 29.1 years and (c) 75 healthy pregnant women (81 samples), mean ag e 28.5 years, used as matched controls. In pregnant women, blood colle ction started at the 10th week of gestation. In 14 women from group b and in 22 from group c blood was withdrawn during labor as well. CRH w as assayed by RIA. Results: Levels in non-pregnant women were between 19.0-40.6 pg/ml (28.37 +/- 2.53 pg/ml, mean +/- S.E.M.). In both group s of pregnant women there was a progressive increase in plasma CRH lev els becoming quite sharp towards the end of gestation. Between 10 and 20 weeks, CRH (mean +/- S.E.M.) in PIH group was 69.3 +/- 3.2 pg/ml ve rsus 41.6 +/- 2.4 pg/ml in matched controls, at 21-25 weeks 168.0 +/- 12.8 pg/ml versus 58.5 +/- 3.8 pg/ml, at 32-35 weeks 1378.5 +/- 61.4 p g/ml versus 298.3 +/- 16.9 pg/ml and at 38 weeks 2800.0 +/- 114.1 pg/m l versus 825.0 +/- 59.8 pg/ml. At term, CRH levels were 3784.0 +/- 197 .3 pg/ml in PIH, versus 1386.0 +/- 101.8 pg/ml in normal pregnancy. St atistically, at every stage of gestation, CRH levels were highly signi ficantly different in the PIH group (P < 0.0005). One hour postpartum there was a c. 60% decrease in plasma CRH levels in both b and c group s. In three women with pre-eclampsia who underwent premature labor due to a dead fetus around the 30th week, very high levels were noticed i n sequential blood samples for 4-5 weeks prior to labor. Conclusions: (a) CRH levels in women with PIH are significantly higher compared to healthy pregnant women at any stage of gestation starting from week 10 ; (b) very high levels during pregnancy might be predictive of prematu re labor or fetal loss; and (c) CRH measurement might prove to be a he lpful diagnostic tool in women with pregnancy-induced hypertension.