Gestational weight gain in uncomplicated twin pregnancies by pre-pregnancy body mass index.

In 2009, the Institute of Medicine provided provisional guidelines for gestational weight gain (GWG) in twin gestations, citing limited research. We examined GWG by pre-pregnancy body mass index in a retrospective cohort of twin births uncomplicated by infant mortality, preterm birth, or low birth weight from Massachusetts in 2006-2017 (N = 273). Median (inter-quartile range [IQR]) GWG was 20.4 kg (IQR: 17.2-25.9 kg) for women who were normal weight pre-pregnancy, 21.3 kg (IQR: 17.2-25.9 kg) for women with overweight pre-pregnancy, and 13.6 kg (IQR: 8.6-20.9 kg) for women with obesity pre-pregnancy. Findings can inform the next generation of GWG recommendations for twin pregnancies.