The effect of increasing obesity on the response to and outcome of assisted reproductive technology: a national study.

OBJECTIVE: To evaluate the effect of increasing female obesity on response to and outcome of assisted reproductive technology (ART) treatment.
DESIGN: Historical cohort study.
SETTING: Clinic-based data. PATIENT(S): A total of 152,500 ART cycle starts from the Society for Assisted Reproductive Technology Clinical Outcomes Reporting System for 2007-2008, limited to women with documented height and grouped by body mass index (BMI, [weight/height(2)]). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Cycle cancellation overall, cycle cancellation due to low response, treatment failure (not pregnant vs. pregnant), and pregnancy failure (fetal loss or stillbirth vs. live birth), as adjusted odds ratios and 95% confidence intervals, with cycles among normal-weight women as the reference group. RESULT(S): Cycle cancellation overall and cancellation due to low response using autologous oocytes significantly paralleled increasing BMI. The odds of treatment failure rose significantly with autologous-fresh cycles, from 1.03 for cycles among overweight women (BMI 25.0-29.9) to 1.53 for cycles among women with BMIs ≥ 50.0 kg/m(2). Likewise, the odds of pregnancy failure were most significant with increasing BMI among women with autologous-fresh cycles, increasing from 1.10 for cycles to overweight women to 2.29 for cycles to women with BMI ≥ 50.0 kg/m(2). CONCLUSION(S): These results indicate significantly higher odds of cycle cancellation. In addition, treatment and pregnancy failures with increasing obesity significantly increased starting with overweight women.