Increased body mass index negatively impacts blastocyst formation rate in normal responders undergoing in vitro...

The aim of this study is to investigate the effect of female BMI and metabolic dysfunction on blastocyst formation rate.

This was a retrospective cohort study that was performed in an academic center for reproductive medicine. Patients who were normal weight, overweight with metabolic dysfunction, or obese who had ≥6 oocytes retrieved in a fresh IVF cycle were included in the study. The blastocyst formation rate was calculated from the number of ≥5 cell embryos on day 3 observed in culture until day 5 or day 6. Only good quality blastocysts were included in the calculation as defined by a morphologic grade of 3BB or better.

The blastocyst formation rate was significantly better in the normal-weight controls versus overweight/obese patients (57.2 versus 43.6 %, p < 0.007). There was no difference in blastocyst formation between the patients with a BMI 25-29.9 kg/m(2) with metabolic dysfunction and those with a BMI ≥30 kg/m(2).

The maternal metabolic environment has a significant impact on embryo quality as measured by blastocyst formation. A decreased blastocyst formation rate is likely a significant contributor to poorer reproductive outcomes in overweight and obese women with infertility.