Objective: To predict pregnancy outcome and multiple gestation using a common parameter by which hCG values are made comparable independently of the day of blood sampling.
Design: Retrospective study.
Setting: University-based IVF program.
Patients: One hundred twenty IVF pregnancies conceived between November, 1995 and August, 1999.
Main outcome measures: Early pregnancy loss (preclinical and first trimester abortions, ectopic pregnancies) or ongoing pregnancies (singleton and multiple deliveries, second trimester abortions). Day 11 hCG levels were calculated assuming an exponential increase of hCG values in early pregnancy. Receiver-operating characteristic analysis was used to determine cut-off levels with the best sensitivity and specificity for the prediction of pregnancy outcome.
Results: Serum hCG levels in the group of early pregnancy loss were significantly lower than in ongoing pregnancies. A cut-off level of 50 IU/L predicts pregnancy outcome with a sensitivity of 75% and a specificity of 81%, while an hCG value >135 IU/L predicts a multiple ongoing pregnancy with a sensitivity of 80% and a specificity of 88%.
Conclusion: After IVF, early pregnancy loss or multiple gestation may be predicted with high sensitivity and specificity by using cut-off values of serum hCG derived from two measurements independently of the day of blood sampling.