Supporting Maternal and Fetal Well-being
Gaining weight during pregnancy is a natural, necessary physiological process that supports your developing baby, the placenta, amniotic fluid volume, increased maternal blood volume, and breast tissue. Understanding clinical weight gain targets helps ensure both mother and baby thrive.
Institute of Medicine (IOM) Recommendations
Recommended total gestational weight gain is categorized by pre-pregnancy BMI:
- Underweight (BMI < 18.5): 28 to 40 lbs (12.5 to 18 kg)
- Normal Weight (BMI 18.5–24.9): 25 to 35 lbs (11.5 to 16 kg)
- Overweight (BMI 25.0–29.9): 15 to 25 lbs (7 to 11.5 kg)
- Obese (BMI ≥ 30.0): 11 to 20 lbs (5 to 9 kg)
Where Does the Weight Actually Go?
At 40 weeks, a typical 30 lb weight gain is distributed as follows:
Baby (~7.5 lbs), Placenta (~1.5 lbs), Amniotic Fluid (~2 lbs), Uterine Enlargement (~2 lbs), Maternal Breast Tissue (~2 lbs), Increased Blood Volume (~4 lbs), Maternal Fluid Retention (~4 lbs), and Maternal Nutrient & Fat Stores (~7 lbs).
Track your pregnancy milestones using our Pregnancy Weight Calculator and Pregnancy Due Date Calculator.