Plasma Corticotropin-Releasing Hormone Concentrations During Pregnancy and Parturition*

Abstract

Plasma CRH was measured in maternal plasma throughout the third trimester of pregnancy, during labor, and postpartum. CRH levels were also measured in arterial and venous umbilical cord plasma samples. In normal pregnant women, plasma CRH increased from 50 +/- 15 (+/- SEM) pg/mL at 28 weeks gestation (n = 41) to 1462 +/- 182 pg/mL at 40 weeks (n = 55) and 1680 +/- 101 pg/mL (n = 65) in labor. Women with pregnancy-induced hypertension (n = 49) had plasma CRH levels significantly elevated above this normal range. Similarly, women who subsequently went into premature labor had raised levels several weeks before the onset of labor. After delivery, plasma CRH returned to normal within 15 h. Total plasma cortisol levels varied little throughout the third trimester, but increased during labor and remained elevated 2-3 days postpartum. There was, therefore, no correlation between plasma cortisol and CRH, implying that this placental CRH is not primarily involved in the control of the maternal hypothalamo-pituitary adrenal axis during pregnancy. The concentrations of CRH in umbilical cord plasma samples were considerably lower than those in the maternal circulation and were close to those in normal nonpregnant adults.

Corticotrophin-releasing hormone and ACTH levels in maternal and fetal blood during spontaneous and oxytocin-induced labour

“…CRH concentrations were the same in both groups and much lower than before delivery. Some investigators found rising CRH levels during term labour (9, 10); others reported no change in plasma CRH as labour progressed (11,12). In all of these studies CRH concentration was measured at the second stage of delivery, whereas we measured its level after delivery of the placenta.…”

Endocrine immune interactions in human parturition

“…In human pregnancy, the placenta releases CRH and maternal plasma CRH levels increase exponentially, peaking at delivery, and returning to pre-pregnancy levels within 24 hours of birth (Campbell et al, 1987, Kalantaridou et al, 2004. Interestingly, placental production of CRH seems to occur only in primate species, again reinforcing the uniqueness of human parturition (Robinson et al, 1989).…”

Lack of Correlation Between Immunoreactive Corticotropin‐Releasing Factor Concentration Profiles in Hypophysial‐Portal and Peripheral Plasma

“…This strongly suggested an alternative, non-hypothalamic origin of irCRF-41 present in the systemic circulation. Multiple sources of peripheral irCRF-41 may be Postulated on the basis of immunohistochemical or content studies (18)(19)(20)(21)(22)(23)(24). Of particular interest were the adrenal glands, which contain and secrete CRF-like immunoreactivity (23,24).…”

“…Several laboratories have reported the presence of irCRF-41 in human or rat peripheral plasma (10)(11)(12)(13)(14)(15)(16)(17). During pregnancy, peripheral irCRF-41 appears to be derived from the placenta (18)(19)(20). The source of peripheral irCRF-41 in non-pregnant animals is unknown and it has been postulated that it may reflect, at least in part, hypothalamic irCRF-41 secretion (13,14,16,17); other sources include the gastrointestinal tract (21), the pancreas (22) and the adrenal gland (23,24).…”