Pre-pregnancy body mass index does not impact live birth rate after
frozen-thawed euploid embryo transfer: a retrospective cohort study
Abstract
Objective To assess the effects body mass index (BMI) on live birth
rates in patients undergoing in vitro fertilization (IVF) with
trophectoderm biopsy and preimplantation genetic testing for
aneuploidies (PGT-A) when transferring a single euploid blastocyst.
Design Retrospective cohort study. Setting Public fertility center in
China. Population 821 women who underwent first cycle of frozen-thawed
single euploid blastocyst transfer between 2012 and 2020. Methods
Patients were grouped by World Health Organization (WHO) BMI class:
underweight (<18.5, n=80), normal weight (18.5-24.9, n=602),
overweight (25-30, n=112), and obese (≥30, n=27). A logistic regression
model was used to assess the association between BMI and live birth
while adjusting for potential confounders. Main outcome measures
Live-birth rate was primary outcome. Results There was no difference in
the birth weight, miscarriage, preterm birth, pregnancy complication,
type of delivery and fetal gender by BMI category. The clinical
pregnancy rate was higher in the overweight and obese groups. In
multivariate logistic regression analysis, we fail to demonstrate a
statistically significant relationship between BMI and live birth in
underweight (adjusted odds ratio [AOR] 0.80; 95% confidence
interval [CI], 0.47-1.35, p=0.402), overweight (AOR 0.85; 95% CI,
0.54-1.35, p=0.491) or obese (AOR 1.07; 95% CI, 0.48-2.38, p=0.864)
patients compared with the normal weight reference group. Conclusion No
statistically significant relationship was identified between BMI and
live birth in patients undergoing IVF with PGT-A, suggesting that the
negative impact of obesity on IVF and clinical outcomes may be related
to aneuploidy.