Positive Association of the Number of Oocyte Retrievals With the Maternal hCG Concentration in Early Pregnancy After in vitro Maturation

In vitro maturation (IVM), which is widely used for infertile women, offers many benefits, and it does not involve ovarian hyperstimulation. In addition, the serum human chorionic gonadotropin (hCG) level is significantly higher in women with early pregnancies achieved by IVM than in those with pregnancies achieved by traditional IVF. In the present study, we explored the association between the number of oocyte retrievals and the maternal hCG concentration on days 14 and 21 after IVM. Data from 51 women who delivered singletons were analyzed. The mean number of oocytes retrieved was 16.78 ± 11.23, and the hCG concentration was 614.47 ± 445.50 IU/L on day 14 and 10930.20 ± 7223.17 IU/L on day 21. After adjusting for confounding factors, the concentration of maternal serum hCG on days 14 and 21 associated significantly with the number of oocyte retrievals. Crude linear regression analysis showed a positive relationship between the number of oocytes retrieved and the hCG concentration. Our results showed that the number of oocytes retrieved associated positively with the serum hCG concentration in women with early pregnancies that underwent IVM. Our results partially explain the transient changes in the early maternal serum hCG concentration after IVM.