Impact of body mass index (BMI) on the success rate of fresh embryo transfer in women undergoing first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment

Objective To investigate the impact of body mass index (BMI) on the success rate and prenatal outcomes of fresh embryo transfer in women undergoing their first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment. Methods It is a post-hoc analysis of a prospective observational cohort study. 2569 Chinese women were grouped in quintiles of BMI and according to the official Chinese classification of body weight. IVF/ICSI and pregnancy outcomes were compared between groups. Results BMI was not associated with IVF/ICSI pregnancy outcomes including hCG positive rate, clinical pregnancy rate, implantation rate, ectopic pregnancy rate, ongoing pregnancy rate, early miscarriage rate, and live birth rate. However, it was negatively related to some pregnancy complications such as gestational diabetes mellitus (GDM) and hypertension. Additionally, the proportion of Cesarean-section was increased with BMI. As for prenatal outcomes, the current results showed no statistical difference in the number of male and female newborn, the proportion of low live birth weight (<2500 g), macrosomia (>= 4000 g) (both in all live birth and full-term live birth), and premature delivery (<37 weeks). Conclusions The current study showed that BMI was not associated with embryo transfer outcomes after fresh embryo transfer in women undergoing their first IVF/ICSI treatment, whereas BMI was associated with GDM and gestational hypertension.