Neonatal outcomes for obese women undergoing in vitro fertilization (IVF)

Abstract

Previous work investigating IVF outcomes in obese women focuses largely on clinical pregnancy rates, live birth rates and maternal complications, but little data exists regarding neonatal outcomes for obese women using IVF. Therefore, we investigated gestational age and birth weight in children born to obese women after IVF. Retrospective cohort. Inclusion criteria were women with a singleton delivery after their first IVF cycle in our center between 2001 and 2008. Women using donor oocytes were excluded. Associations between maternal body mass index (BMI), gestational age and birth weight at delivery were investigated after classifying women into one of three BMI groups: normal (less than 25 kg/m2), overweight (25-29 kg/m2), and obese (greater than or equal to 30 kg/m2). T- tests and chi-square analysis were used to determine differences in neonatal outcomes between the normal-weight group and the other groups. 206 women met study criteria. Obese women had a significantly higher fraction of preterm births than normal-weight women (37 vs. 21%, p=0.01). Overweight women had a larger fraction of large for gestational age (LGA) infants (31 vs. 20%, p=0.05) when compared to normal-weight women. Overweight women had heavier infants compared to normal-weight women, although this difference was not statistically significant (7.02 vs. 6.74 lbs, p=0.1). Overall infants born to obese women weighed significantly less when compared to infants born to normal weight women (6.29 vs. 6.74 lbs, p=0.05), which may be attributed to the significantly higher fraction of preterm births among obese women. Our findings provide evidence that higher maternal BMI in IVF patients translates into adverse neonatal outcomes including higher incidence of preterm birth, and for infants born at term an increased risk of LGA. This is concerning as preterm birth and LGA at term are known to adversely impact chronic health conditions and development in children.