Recommended pregnancy weight gain by pre-pregnancy BMI per the U.S. Institute of Medicine guideline (IOM, 2009). Supports singleton and twin pregnancies and provides target range and weekly increments.
Target pregnancy weight gain based on the U.S. Institute of Medicine guideline (Institute of Medicine, 2009), updated by the Pregnancy and Birth Outcomes Working Group. Used in obstetrics, antenatal care, and perinatal centers to assess adequacy of weight gain and risk of macrosomia, gestational diabetes, preeclampsia, and low birth weight. Targets depend on pre-pregnancy BMI. Singleton pregnancy: underweight (BMI <18.5) – 12.5–18 kg, normal weight (18.5–24.9) – 11.5–16 kg, overweight (25–29.9) – 7–11.5 kg, obese (≥30) – 5–9 kg. Twin pregnancy: normal weight – 17–25 kg, overweight – 14–23 kg, obese – 11–19 kg. Trimester distribution: 1–2 kg in the first trimester, then 0.4 kg/week underweight, 0.4 kg/week normal, 0.3 kg/week overweight, 0.2 kg/week obese. Gain below target increases risk of preterm birth, intrauterine growth restriction, and low birth weight. Gain above target raises risk of gestational diabetes, preeclampsia, cesarean delivery, macrosomia, and persistent postpartum weight retention. In gestational diabetes, class III obesity, or after bariatric surgery, targets are individualized by the obstetrician.
Formula version: iom-2009-acog-2024-v1
Calculators