Association analysis of body mass index on ovarian response and pregnancy outcomes during IVF / ICSI treatment: a retrospective study in Southern Han Chinese Women

Abstract

Background: The purpose of the present study is to evaluate the effect of body mass index (BMI) on cycle characteristics and in vitro fertilization / intracytoplasmic sperm injection (IVF / ICSI) outcomes of a long down-regulation protocol in Southern Han Chinese women. Methods : This retrospective, observational study included 5279 infertile women undergoing IVF / ICSI cycle with a long down-regulation protocol. All the patients were divided into four subgroups by the recommended Chinese BMI cut-off points: underweight, BMI < 18.5 kg/m 2 ; normal-weight, 18.5 kg/m 2 ≤ BMI < 24.0 kg/m 2 ; overweight, 24.0 kg/m 2 ≤ BMI < 28.0 kg/m 2 ; obese, BMI ≥ 28.0 kg/m 2 . The demographic data and biochemical tests of patients, the parameters related to the ovarian responsiveness to gonadotrophin stimulation, IVF / ICSI treatment characteristics and pregnancy outcomes (clinical pregnancy rate, spontaneous abortion rate and lived birth rate) were compared among BMI categories. Results: The overweight patients had lower ovarian sensitivity index (OSI) ( P < 0.05) and higher spontaneous abortion rate than women in the normal-weight (13.59% vs. 10.28%, OR = 2.37, 95% CI: 1.35 – 4.16, P = 0.003 ). The overweight and obese patients seemed to have lower clinical pregnancy rate and live birth rate, but the difference was not statistically significant ( P > 0.05). Conclusion: This study provides new epidemiological clues that the elevated BMI might increase the risk of spontaneous abortion and impair ovarian response to gonadotropin stimulation during IVF / ICSI treatment.