Overweight and obesity negatively affect the outcomes of ovarian stimulation and in vitro fertilisation: a cohort study of 2628 Chinese women.

OBJECTIVE: To explore the effects of overweight and obesity on the outcomes of in vitro fertilisation (IVF) in Chinese infertile patients. STUDY
DESIGN: A retrospective cohort study was carried out in 2222 normal weight (18.5 <or= BMI < 25), 379 overweight (25 <or= BMI < 30) and 27 obese (BMI >or= 30) women who underwent their first IVF cycles between 2002 and 2008. Cycle characteristics and IVF outcomes were analysed.
RESULTS: Obese women required significantly higher dose of rFSH (3272 IU vs. 2587 IU, p < 0.001) and days of stimulation (11.89 +/- 4.57 vs. 10.42 +/- 2.03, p < 0.001), but exhibited less oocytes retrieved and significantly lower fertilisation rate (54.1% vs. 61.1%, p < 0.001) than normal weight women. Compared with normal weight women, overweight women displayed significantly less oocytes retrieved (12.98 +/- 6.91 vs. 14.49 +/- 7.96, p < 0.001), lower fertilisation rate (60.8 +/- 23.3 vs. 61.1 +/- 23.0, p < 0.001), less cleavaged embryos (7.55 +/- 4.86 vs. 8.67 +/- 5.90, p < 0.001), less high-grade embryos (4.65 +/- 3.96 vs. 5.59 +/- 4.81, p < 0.001) and cryopreserved embryos (4.44 +/- 4.55 vs. 5.49 +/- 5.55, p < 0.001). All parameters of pregnancy outcomes, including pregnancy rate, miscarriage rate and live birth rate, were comparable among three groups.
CONCLUSIONS: Overweight and obesity are related with impared ovarian response, and negatively affect the outcomes of IVF.