Relationship between serum human chorionic gonadotrophin levels and body mass index in women undergoing in vitro fertilisation cycles.

Objective: To ascertain if serum concentrations following injection of human chorionic gonadotropin (hCG) influenced the outcome of in vitro fertilisation (IVF) treatment and correlated to body mass index (BMI).

Study Design: A prospective study conducted with the participation of 149 women undergoing IVF and/or intracytoplasmic sperm injection (ICSI) treatment at the regional IVF Unit in Liverpool, UK. The BMI of each individual was calculated and serum hCG concentrations were measured at 12 and 36 h following a subcutaneously (SC) injection of 5000 IU hCG. The main outcome measures were fertilisation rate and biochemical pregnancy rate.

Results: No correlation was found between serum hCG levels at 12 and 36 h with the number of oocytes retrieved or the number of oocytes fertilised. Furthermore, there was no correlation between BMI and hCG levels at 12 and 36 h following administration (Pearson's correlation coefficient: -0.23, -0.24, respectively).

Conclusion: Our results suggest that the serum concentrations of hCG do not influence IVF outcome and that the serum levels of hCG achieved following administration do not correlate with the individual's BMI. Serum hCG concentration also does not correlate with number of oocytes collected or fertilisation rate.