Association between pre-pregnancy BMI and neonatal weight outcomes in twin pregnancies resulting from assisted reproductive technology: a 10-year cohort study.

Among mothers undergoing ART, pre-pregnancy maternal obesity is associated with higher birth weight and higher risk of preterm birth for twin pregnancy, and pre-pregnancy maternal underweight is associated with lower birth weight and higher risk of SGA. Women preparing for ART should maintain a normal BMI to lower the chances of adverse neonatal outcomes.