Association between embryo morphological quality and birth weight for singletons conceived via autologous fresh embryo transfer: an analysis using Society for Assisted Reproductive Technology Clinical Outcomes Reporting System

Objective: To determine if morphologically suboptimal embryo quality is associated with adverse perinatal outcomes. Design: A retrospective cohort. Setting: SART CORS database. Patient(s): Singletons conceived from autologous in vitro fertilization fresh cycles. Intervention(s): None. Main Outcome Measure(s): Birth weight (gram), birth weight z-score, low birth weight (LBW), small for gestational age (SGA), and large for gestational age (LGA). Result(s): Among 5,869 in vitro fertilization fresh cycles, 71.1% transferred morphologically good embryos, and 27.0% and 1.9% transferred fair and poor embryo(s), respectively. Compared with singletons conceived from good embryos, singletons from poor embryos had a higher birth weight (3,415.8 ± 562.0 vs. 3,202.7 ± 639.9). Proportions of LBW, SGA, and LGA were comparable across embryo quality groups. Multivariate regression analysis comparing perinatal outcomes from fair vs. good embryos showed no association for birth weight (0.69-gram difference; 95% CI, -24.30–25.68), birth weight z-score (Coefficient, 0.00; 95% CI, -0.07–0.08), LBW (adjusted odds ratio [aOR], 0.84; 95% CI, 0.63–1.11), SGA (aOR, 0.93; 95% CI, 0.78–1.11), and LGA (aOR, 1.07; 95% CI, 0.86–1.33). Stratified analysis, considering cleaved and blastocyst embryo transfers separately, confirmed these findings. Sensitivity analysis revealed increased odds of LGA (aOR, 1.53; 95% CI, 1.04–2.24) with fair-quality embryos only among single embryo transfer cycles. Conclusion(s): Once a singleton live birth from fresh embryo transfer is achieved, fair morphological embryo quality is not associated with a reduction in birth weight or increased risks of LBW, SGA, and LGA.