MATERNAL PLASMA CORTICOTROPIN-RELEASING HORMONE - ELEVATED IN PRETERM LABOR BUT UNAFFECTED BY INDOMETHACIN OR NYLIDRIN

The role of corticotrophin-releasing hormone (CRH) in preterm labour was studied in 23 women in preterm labour at between 26 and 33 weeks gestation who were randomly allocated to receive treatment with indomethacin (n = 11) or with nylidrin a beta-sympathomimetic agent (n = 12). Maternal plasma CRH in the preterm group (median 70, range 9-597 pmol/l) before therapy was higher (P < 0.05) than that iin 23 control pregnancies, without uterine contractions, matched for gestational age (median 51, range 4-127 pmol/l). CHR levels determined after 3 and 24 h of treatment showed a 10% decrease in the indomethacin group and 10-20% decrease in the nylidrin group, but thse changes were not statistically significant. After cessation of uterine contractions during tocolysis, 12 women proceeded to give birth preterm (< 37 weeks) and their pretreatment CRH levels (median 195, range 9-597 pmol/l) were higher (P < 0.05) than those in women whose pregnancy proceeded to term (median 52, range 16-207 pmol/l). In another group of women, full-term labour was not accompanied by any changes in maternal CRH levels. Umbilical plasma CRH levels were 1.1-9.8% of the paired maternal levels and did not rise with advancing gestational age. Nor had the type of delivery (elective caesarean section before labour, or preterm or term vaginal delivery) any effect on fetal CRH levels. Neither maternal nor fetal CRH was related to maternal or fetal cortisol levels. We conclude that: (i) maternal CRH is elevated in preterm labour, (ii) maternal CRH is not affected by treatment with indomethacin or nylidrin and (iii) fetal CRH is of no significance in the initiation of preterm or term labour.