Effect of body mass index on in vitro fertilization outcomes in women with polycystic ovary syndrome.

OBJECTIVE

The objective of the investigation was to study the effect of body mass index (BMI) on in vitro fertilization (IVF) outcomes within a polycystic ovary syndrome (PCOS) population.

STUDY

DESIGN

This was a retrospective cohort study including 101 cycles from 79 women younger than 40 years old with a clinically documented diagnosis of PCOS by Rotterdam criteria undergoing IVF at a university-based infertility clinic from 2001 through 2010. All participants were stratified by BMI calculated from height and weight recorded within 3 months of cycle start: lean (18.7-24.9 kg/m(2), n = 51), overweight (25-29.9 kg/m(2), n = 19), and obese (≥30 kg/m(2), n = 31). Linear, logistic, and Poisson regressions were used as appropriate to estimate the effect of a range of BMIs on IVF outcomes while adjusting for potential confounders.

RESULTS

Obese PCOS women had 69% lower odds of clinical pregnancy per cycle start (odds ratio [OR], 0.31; 95% confidence interval [CI], 0.11-0.86; P = .02) and 77% lower odds of clinical pregnancy per embryo transfer (OR, 0.23; 95% CI, -0.08 to 0.68; P = .008) compared with lean PCOS women. Among obese PCOS women, the odds of live birth were 71% lower per cycle start (OR, 0.29; 95% CI, 0.10-0.84; P = .02) and 77% lower per embryo transfer (OR, 0.23; 95% CI, 0.07-0.71; P = .01) compared with lean PCOS women. There was a trend toward decreased ovarian hyperstimulation syndrome incidence with increasing BMI among women with PCOS: 19.6% in lean, 10.5% in overweight, and 3.2% in obese.

CONCLUSION

PCOS is a broad syndrome, with our results demonstrating 2 distinct populations, lean and obese, which have different IVF outcomes including ovarian hyperstimulation syndrome risk profiles. This information is important for clinicians because it informs treatment decisions.