Biochemical discrimination of pathologic pregnancy from early, normal intrauterine gestation in symptomatic patients.

The authors have examined the utility of using the rate of change of the human chorionic gonadotropin (hCG) level and progesterone concentration to distinguish ectopic from normal intrauterine pregnancies. Patients suspicious for ectopic pregnancy had three outcomes: normal intrauterine gestation (NIUG), ectopic pregnancy (ECT), and inevitable abortion (IAB). The rate of change of the hCG level and the progesterone concentration distinguish NIUG from ECT with good sensitivity and specificity at optimal cut-offs of 0.14 (rate of change of the logarithm of hCG) and 8 ng/mL (progesterone). As the biochemical parameters of the ECT and IAB groups overlap, stating that NIUG can be biochemically distinguished from ECT is misleading. Thus, the authors have grouped them together as pathologic pregnancies (PATH). The rate of change of the hCG level and the progesterone concentration distinguish NIUG from PATH with good sensitivity and specificity with the same optimal cut-offs of 0.14 (rate of change of the logarithm of hCG) and 8 ng/mL (progesterone).