Endocrinologic events in early pregnancy failure

Fourteen women experiencing early pregnancy failure have been studied during the time of conception and at frequent intervals until spontaneous abortion occurred. Serial measurements of serum estradiol, progesterone, 17α-hydroxyprogesterone, prolactin, human placental lactogen (hPL), and human chorionic gonadotropin (hCG) were determined; regular sonar scanning allowed the time of fetal death to be determined to within 7 days in six patients and a diagnosis of blighted ovum to be made in the remainder. In all patients serum progesterone and estradiol concentrations were within the normal range up to 7 weeks but appeared to decrease from about 8 weeks' gestation whether or not a living fetus was present. The placenta continued to produce hCG and hPL but, despite the continuing presence of hCG, the levels of 17α-hydroxyprogesterone declined to concentrations below those associated with normal pregnancy. These data suggest that the placenta may require a particular stimulus to take over production of progesterone and estradiol.