Baseline non-fasting serum leptin concentration to body mass index ratio is predictive of IVF outcomes

BACKGROUND: The present study was designed to determine whether circulating leptin concentrations and/or body mass index (BMI) in women undergoing IVF are predictive of outcomes. METHODS: IVF cycle outcomes, e.g. fertilization, embryo development, implantation, pregnancy, were analysed relative to baseline (i.e. day gonadotrophin stimulation was initiated) non-fasting serum leptin concentrations and BMI. RESULTS: Serum leptin concentrations correlated with BMI (r = 0.739, P < 0.0001) as expected. Multiple logistic regression analyses showed correlation between serum leptin and pregnancy success (likelihood ratio = 5.198, P < 0.05), but there was no association between pregnancy and BMI. However, the serum leptin to BMI ratio was more strongly correlated (likelihood ratio = 7.258, P < 0.01) with pregnancy success than was leptin alone. Moreover, women with a low leptin:BMI ratio (< or =0.3) had significantly more superior quality embryos on day 3 post-retrieval (2.5 versus 1.4, P < 0.05, Kruskal-Wallis) and a greater implantation rate (26.7 versus 13.2%, P < 0.025, chi(2)) than women with a high leptin:BMI ratio (> or =0.7). CONCLUSIONS: The leptin:BMI ratio appears to be highly predictive of IVF success. Elevated leptin concentrations, particularly relative to BMI, may negatively impact fertility by assisted reproduction, possibly through direct ovarian actions resulting in impaired oocyte quality and/or early embryo development.