Objective: Analysis of serum beta-human chorionic gonadotropin (beta-hCG) levels on standardized days after oocyte retrieval (OR) following single blastocyst transfer to predict pregnancy outcome after assisted reproductive technology.
Design: Retrospective study.
Setting: Private fertility center.
Population: A total of 230 women with an intact intrauterine pregnancy 21 days after OR and a vital term delivery (n = 191) or a miscarriage (< 10+0 gestational weeks) (n = 39) in the course of the pregnancy following single blastocyst transfer between 1999 and 2008.
Methods: Blood was sampled 11, 14 and partly 21 days after OR. The serum concentration of total beta-hCG was measured by an automated quantitative immunoassay. Receiver operating characteristic curves were generated to calculate sensitivity and specificity.
Main outcome measures: A total of 509 beta-hCG measurements.
Results: The mean beta-hCG concentrations on days 11, 14 and 21 after OR were significantly lower in the group of patients with a miscarriage compared to the group with a term delivery (p = 0.02, < 0.001 and < 0.001 respectively). With the cut-off values of 15 mIU/mL, 80 mIU/mL and 1500 mIU/mL on days 11, 14 and 21, the positive predictive value was 89%, 93% and 92%. The negative predictive value was 28%, 40% and 54%.
Conclusions: The predictive value of a single beta-hCG measurement for pregnancy outcome after single blastocyst transfer increases between days 11 and 21 after OR. A single beta-hCG measurement on day 14 may balance the accuracy of prediction and the necessity of an early reassuring test.