The Utility of Plasma CRH as a Predictor of Preterm Delivery

• Published in: The journal of clinical endocrinology and metabolism 2001-12, Vol.86 (12), p.5706-5710
• Main Authors: Inder, Warrick J., Prickett, Timothy C. R., Ellis, M. Jane, Hull, Louise, Reid, Rosemary, Benny, Peter S., Livesey, John H., Donald, Richard A.
• Format: Article
• Language: English
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jcem.86.12.8080

It has been suggested that CRH is a placental clock that controls the duration of pregnancy and that the timing of the rise in CRH may permit prediction of the onset of labor. We have performed a prospective longitudinal study, in 297 women, to examine the utility of a single second-trimester plasma CRH measurement to predict preterm delivery. Venous blood samples were taken at 4-weekly intervals, beginning at 16–20 wk gestation, until delivery for CRH and its binding protein. A time point at which a single plasma CRH test might give optimal data to predict preterm delivery was determined. Thirty-one subjects delivered prematurely (10.4%). Sampling for plasma CRH at 26 wk gestation seemed the optimal time point to maximize sensitivity and specificity of the test. The mean (± sd) plasma CRH in women at this gestation who eventually delivered after spontaneous labor within 1 wk of their due date (39–41 wk, n = 127) was 34.7 ± 27.0 pm. A plasma CRH of more than 90 pm at 26 wk gestation had a sensitivity of 45% and a specificity of 94% for prediction of preterm delivery. The positive predictive value was 46.7%. Calculation of free CRH did not improve these figures. In conclusion, a single measurement of plasma CRH, toward the end of the second trimester, may identify a group at risk for preterm delivery, but over 50% of such deliveries will be unpredicted. These data do not support the routine clinical use of plasma CRH as a predictor of preterm labor.