Human chorionic gonadotropin serum levels following ovulation triggering and IVF cycle outcome

The clinical significance of serum hCG levels after ovulation triggering was studied previously with conflicting results. Our aim was to study the correlation of hCG levels on the day after ovulation triggering using recombinant hCG (r-hCG) with treatment outcome.

A prospective observational study of all fresh IVF/ICSI cycles in a single medical center, between January 2015 and June 2016, was performed. hCG serum levels were obtained 10-12 h following ovulation triggering with 250 mcg r-hCG. Clinical and laboratory outcome parameters were compared between cycles with serum hCG above and below median level. A multivariate regression analysis was performed in order to study the association between hCG levels and live birth rate, after controlling for confounders.

Overall, 326 cycles were included. Median serum hCG level was 91.35 IU/L. hCG levels were lower as age and BMI were higher (p = 0.004, p < 0.001, respectively). The study groups did not differ with regard to clinical pregnancy rate (p = 0.14), live birth rate (p = 0.09), fertilization rate (p = 0.45), or metaphase II oocyte rate (p = 0.68). On multivariate regression analysis, hCG level was not associated with live birth (aOR 0.99, 95% CI 0.98-1.005), after controlling for patient's age and BMI.

hCG levels on the day after ovulation triggering with 250 mcg r-hCG are inversely correlated with patient age and BMI. However, they are not correlated with any clinical or laboratory outcome parameter. Therefore, testing for hCG levels after ovulation induction seems futile and cannot be recommended.