The utility of plasma CRH as a predictor of preterm delivery.
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.
Inder
W J
WJ
Department of Endocrinology, Christchurch Hospital, 8001 New Zealand.
Prickett
T C
TC
Ellis
M J
MJ
Hull
L
L
Reid
R
R
Benny
P S
PS
Livesey
J H
JH
Donald
R A
RA
D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D007752:Obstetric Labor, Premature; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity
D003346:Corticotropin-Releasing Hormone