Plasma corticotrophin‐releasing factor (CRF) in normal pregnancy

Abstract
Summary. Corticotrophin‐releasing factor (CRF) was measured directly in maternal plasma using an immunoradiometric assay (IRMA). In the first and second trimester CRF levels were within the non‐pregnant range (mean 15 pg/ml). A total of 72 women was followed sequentially from 28 weeks until delivery and CRF levels rose from a median of 20 pg/ml at 28 weeks to 1320 pg/ml at 40 weeks and 1732 pg/ml during labour. There was a strong correlation (rs= 0·81, Ps= 0·36, Ps= 0·54, P<0·01).