Two hundred twenty consecutive in vitro fertilization (IVF) conception cycles were studied prospectively in order to examine the predictive value of serum human chorionic gonadotropin beta-subunit (beta-hCG), estradiol (E2), and progesterone (P) in predicting pregnancy outcome between 2 and 4 weeks after oocyte collection. To examine the predictive value of each hormone in predicting clinical pregnancy outcome, each patient's result at each week was assigned a scoring system based on the 25th percentile value of the concentration of beta-hCG, E2, and P in ongoing singleton IVF pregnancies for each week of the study. All but one ectopic pregnancies had scores of 0 or 1 points between 2 and 4 weeks after oocyte collection. The scores in successful pregnancies were significantly higher than in unsuccessful pregnancies 2 weeks after oocyte collection. Ninety percent of women scoring 3 points 2 weeks after oocyte collection had ongoing IVF pregnancies. The authors conclude that determination of serum beta-hCG, E2, and P concentrations between 2 and 4 weeks after oocyte collection provides clinically useful information not only in the prediction of ectopic IVF pregnancy, but also, conversely, in the identification of IVF pregnancies that are destined to be ongoing.