Pregnancy Weight Gain Calculator
Healthy weight gain during pregnancy supports your baby's growth and development. This calculator uses the Institute of Medicine (IOM) guidelines to recommend total weight gain based on your pre-pregnancy BMI and tracks your progress throughout pregnancy.
The Institute of Medicine established weight gain recommendations for pregnancy based on pre-pregnancy BMI. Women who are underweight before pregnancy are advised to gain more weight (12.5-18 kg) to support fetal growth, while women who are obese are advised to gain less (5-9 kg) to reduce complications.
Weight gain during pregnancy is not evenly distributed. In the first trimester, only 0.5-2 kg of gain is typical. Most weight gain occurs in the second and third trimesters at a steady weekly rate. The weight gained includes the baby (3-3.5 kg), placenta (0.7 kg), amniotic fluid (0.8 kg), increased blood volume (1.5 kg), uterine growth (1 kg), breast tissue (0.5-1.5 kg), fat stores (2.5-4 kg), and increased fluids (1.5-2.5 kg).
Both insufficient and excessive weight gain carry risks. Inadequate gain increases the risk of preterm birth and low birth weight. Excessive gain increases the risk of gestational diabetes, preeclampsia, cesarean delivery, and postpartum weight retention. This calculator provides general guidance; always follow your healthcare provider's specific recommendations.