Serial beta-subunit human chorionic gonadotropin doubling time as a prognosticator of pregnancy outcome in an infertile population.

Prospective evaluation through the use of radioimmunoassay of the beta-subunit of human chorionic gonadotropin (beta-hCG) in blood samples obtained during the first 30 days of gestation was performed on an infertile population at high risk for pregnancy loss. Four hundred and fourteen samples in 281 pregnancies were analyzed. On the basis of single, random beta-hCG samples in asymptomatic patients, 77% of successful pregnancies and 59% of abortions were correctly identified. On the basis of beta-hCG doubling time (mean 2.2 days +/- 1.0 [2 SD]) computed from serial sampling, again in asymptomatic patients, 88% of successful pregnancies and 76% of abortions were correctly identified. beta-hCG doubling time appears to provide a reliable method of evaluating early pregnancy prognosis with significantly greater ability to identify problem pregnancies within the first 30 days of gestation than does single random hCG values.