Corticotropin-releasing hormone in amniotic fluid during gestation and labor and in relation to fetal lung maturation

Corticotropin-releasing hormone was discovered in the placenta, and its concentration in the maternal plasma was found to increase greatly during the latter half of pregnancy. We studied the concentration of immunoreactive corticotropin-releasing hormone in amniotic fluid in 59 uncomplicated and in 73 complicated pregnancies. The mean (± SE) value of corticotropin-releasing hormone in amniotic fluid in uncomplicated pregnancies was significantly higher in the third (24.1 ± 3.3 pmol/L) than in the second (9.1 ± 0.7 pmol/L) trimester, but no change was found during labor. In groups matched by gestational age, larger mean values of corticotropin-releasing hormone and cortisol were observed in the group in which the lecithin/sphingomyelin ratio was