Oocyte morphological abnormalities in overweight women undergoing in vitro fertilization cycles

The effect of elevated body mass index (BMI) on the oocyte quality was investigated in women undergoing in vitro fertilization (IVF) cycles. A total of 268 patients classified on the basis of BMI subject to the first reproductive treatment were included in this study: the normal weight (NW) group consisted of 160 patients with BMI 19-24.9 kg/m(2) and the overweight (OW) group consisted of 108 patients with BMI >= 25 kg/m(2). All women were treated with a standard long luteal protocol. The oocyte features were classified as extracytoplasmic or cytoplasmic abnormalities. Outcomes were oocyte morphology, embryo quality, fertilization and implantation rates, and the ovarian response to stimulation. A higher percentage of oocytes with granular cytoplasm was found in women with BMI >= 25 (p = 0.04). However, percentages of mature, immature oocytes and germinal vesicle were similar in both groups. No differences were found in fertilization and cleavage rates and percentages of embryo quality. The implantation rate (p < 0.001) was significantly lower in the OW group than in the NW group. The amount of gonadotrophins was significantly higher in OW group (p = 0.003). These findings suggest that the poor reproductive outcome of obese women is influenced by the release of ova with reduced fertilization potential.