Increased maternal hCG concentrations in early in vitro pregnancy with elevated basal FSH

OBJECTIVE: To investigate factors that influence maternal hCG concentration in early pregnancy and the relationship between hCG concentration in early pregnancy and basal FSH (bFSH) level. DESIGN: Retrospective cohort study. SETTING: Reproductive medical center. PATIENT(S): In total, 482 women aged 22 to 38 years with elevated basal FSH (> 10 IU/L) and who experienced a single live birth after in vitro fertilization-embryo transfer were selected. These 482 women were age-matched with an equal number of women with normal basal FSH (≤10 IU/L) who also experienced a single live birth. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): HCG concentration. RESULT(S): The hCG concentrations on Day 14 and Day 21 were 560.46 (363.63–842.52) IU/L and 9862.00 (6512.25–14029.50) IU/L, respectively, in the elevated bFSH group, and these values were significantly increased compared with the normal bFSH group. After adjusting for confounding factors, the concentrations of maternal hCG on Day 14 and Day 21 were significantly associated with basal FSH. In addition, crude linear regression analysis demonstrated that hCG concentrations increased as the basal serum levels of FSH increased. CONCLUSION(S): Elevated basal FSH has implications for the interpretation of hCG concentrations in early pregnancy after in vitro fertilization-embryo transfer (IVF-ET) that led to a single live birth.