Suboptimal progesterone production in pathologic pregnancies.

Abstract

Serum progesterone (P) levels were determined at the time of routine prenatal registration (227 patients) or upon presentation for evaluation of vaginal bleeding and/or abdominopelvic cramping/pain (135 patients). P associated with a normal intrauterine gestation was 24.63 +/- 4.19 (SD) ng/mL as compared with 6.29 +/- 2.43 ng/mL and 6.02 +/- 2.39 ng/mL for spontaneous abortions and ectopic gestations, respectively. Further, P differed between asymptomatic (11.92 +/- 9.61 ng/mL) and symptomatic patients (4.81 +/- 3.92 ng/mL) who were subsequently shown to have an abnormal gestation. By establishing a P cutoff point of < or = 14.2 ng/mL and < or = 10.5 ng/mL in asymptomatic and symptomatic patients, respectively, 100% screening sensitivity was reached, and therefore no abnormal gestations would escape detection in our study population. P was either in the normal or abnormal range as early as four weeks' estimated gestational age and persisted as such through the luteal-to-placental shift and up to the time of pregnancy loss or 12 weeks' estimated gestational age. Although there was no significant correlation between P and chorionic gonadotropin levels and pregnancy outcome, the binding constant for native chorionic gonadotropin was 15-52 times lower in 12 of 41 cases of spontaneous abortion but not ectopic gestation, suggesting a possible molecular basis for suboptimal P production. P is therefore an excellent adjunctive marker for prediction of early pregnancy outcome, and in some cases qualitative abnormalities in chorionic gonadotropin may dictate its production.