Pregnancy Weight Gain Calculator

The Institute of Medicine (IOM) guidelines are the standard reference. For normal-weight women (BMI 18.5–24.9), the recommended range is 25–35 pounds total. Underweight women (BMI < 18.5) are advised to gain 28–40 lbs. Overweight women (BMI 25–29.9) are advised to gain 15–25 lbs. Obese women (BMI ≥ 30) are advised to gain 11–20 lbs. Always follow your healthcare provider's specific guidance.

Most women gain 1–5 pounds in the first trimester (weeks 1–12). Weight gain is slow because the baby is still very small. Many women actually lose weight in the first trimester due to morning sickness and food aversions. The main focus in the first trimester is nutrition quality, not weight quantity.

At term, a typical 30-pound gain breaks down roughly as: baby (7.5 lbs), placenta (1.5 lbs), amniotic fluid (2 lbs), uterine growth (2 lbs), breast tissue (2 lbs), increased blood volume (4 lbs), and body fat/fluid stores (about 7 lbs). The fat stores are the body's energy reserve for breastfeeding and postpartum recovery.

Inadequate weight gain is associated with low birth weight, preterm birth, and developmental concerns. If you're consistently gaining below the recommended rate, your OB may recommend dietary changes, nutritional counseling, or additional monitoring. Don't attempt to increase weight gain rapidly — steady, gradual gain is the goal. Always discuss concerns with your provider.

Gaining above the recommended range is associated with higher risk of gestational diabetes, preeclampsia, C-section delivery, and postpartum weight retention. However, pregnancy is not the time for dieting. If you're concerned about weight gain, speak with your OB or a registered dietitian who specializes in prenatal nutrition — they can help you adjust your eating pattern without restricting necessary nutrients.