NEW ORLEANS — Overweight is a significant risk factor for poor in vitro fertilization success rates, particularly in African American women, according to the results of a new study.
“It is highly recommended that patients be encouraged to lose weight,” advised Dr. Mohamed Mitwally, who presented the findings at the annual meeting of the American Society for Reproductive Medicine.
There is conflicting evidence in the literature regarding the impact of obesity on in vitro fertilization (IVF) success rates, said Dr. Mitwally of Wayne State University, Detroit. But many previous studies have not controlled for confounding risk factors, he said.
His study analyzed 193 consecutive patients undergoing IVF, 161 white and 32 black patients. After controlling for age, infertility diagnosis and duration, number of prior IVF cycles, and ovarian stimulation protocol, the study found a significant difference in pregnancy rates among patients with a body mass index (BMI) of 25 kg/m2 or less, compared with those who had a higher BMI.
Overall, patients with lower BMIs had a clinical pregnancy rate of 51% per cycle, compared with a rate of 35% in patients with higher BMIs. Overweight had a negative impact in both white and black women, but it was more pronounced in the latter group, said Dr. Mitwally. Overweight white women had a pregnancy rate of 38%, compared with a rate of 50% in those who were normal weight, while overweight black women had a pregnancy rate of 19%, compared with 67% in those who were normal weight.