How much weight should I gain during pregnancy?

Recommended gain by starting BMI

How much weight to gain depends on your body mass index before pregnancy. The Institute of Medicine ranges below, used by the CDC, are for a single baby.

These are targets to discuss with your provider, who will track your gain over time rather than focus on any single number.

• Underweight (BMI under 18.5): gain 28 to 40 pounds
• Normal weight (BMI 18.5 to 24.9): gain 25 to 35 pounds
• Overweight (BMI 25 to 29.9): gain 15 to 25 pounds
• Obese (BMI 30 or higher): gain 11 to 20 pounds

Carrying twins

Twin pregnancies call for more weight gain, also based on your starting BMI. The Institute of Medicine ranges below are provisional but widely used.

There is no official range for people who start a twin pregnancy underweight, because there is not enough data, so your provider will set an individualized goal.

• Normal weight: gain 37 to 54 pounds
• Overweight: gain 31 to 50 pounds
• Obese: gain 25 to 42 pounds

How gain is paced and where it goes

Most of the gain comes in the second and third trimesters. The first trimester typically adds only a few pounds, often about 1 to 4 pounds. After that, someone with a normal starting BMI gains roughly 1 pound per week.

The number on the scale is not just the baby. A full-term baby is about 7 to 8 pounds, and the rest is the placenta, amniotic fluid, a larger uterus, increased blood volume, larger breasts, and maternal fat stores that support breastfeeding.

"Eating for two" and why the range matters

Eating for two is a myth in terms of calories. You do not need extra calories in the first trimester, then about 340 additional calories a day in the second trimester and about 450 in the third.

Staying within your range protects you and the baby. Gaining too much raises the risk of a large baby, cesarean delivery, and high blood pressure disorders like preeclampsia, while gaining too little raises the risk of preterm birth and low birth weight. Aim for steady, gradual gain rather than rapid swings.

Related questions

How much weight should I gain if my BMI is normal?

With a pre-pregnancy BMI of 18.5 to 24.9, the guideline for a single baby is 25 to 35 pounds, with most of the gain in the second and third trimesters at roughly 1 pound per week.

How much weight should I gain with twins?

For twins, the Institute of Medicine suggests 37 to 54 pounds if you start at a normal weight, 31 to 50 pounds if overweight, and 25 to 42 pounds if obese. There is no official range for starting a twin pregnancy underweight.

Do I really need to eat for two?

No. You need no extra calories in the first trimester, about 340 extra a day in the second, and about 450 in the third. That is far less than doubling your intake.

What are the risks of gaining too much or too little?

Gaining too much raises the risk of a large baby, cesarean delivery, and high blood pressure disorders such as preeclampsia. Gaining too little raises the risk of preterm birth and low birth weight.

Sources & further reading

1. CDC — Weight Gain During Pregnancy
2. Institute of Medicine (NASEM) — Weight Gain During Pregnancy: Reexamining the Guidelines
3. Institute of Medicine (NASEM) — Composition of Gestational Weight Gain
4. CDC MMWR — Gestational Weight Gain QuickStats

This article reflects current AAP, CDC, and other public-health guidance and is for educational purposes only. It does not constitute medical advice. ParentFlow is a wellness companion — not a substitute for your pediatrician. For any medical concern, contact your healthcare provider.