Weight Gain During Pregnancy: An Ob-Gyn Shares What You Need to Know

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Medically Reviewed By:
Mark Arredondo, M.D.

Pregnancy is a time filled with excitement and anticipation. While there are many things to look forward to, there's one aspect that some women might concerned about: How much weight do you gain during pregnancy?

This article will explore how much women can expect to gain, on average, during each trimester, and what constitutes a healthy weight gain, as explained by a veteran obstetrician-gynecologist.

When do you start gaining weight in pregnancy?

Pregnancy is split into trimesters: the first spans the initial 12 weeks; the second trimester covers weeks 13 to 26; and the final trimester extends from week 27 until the end of the pregnancy, according to Nemours Kids Health.

“Most women start gaining weight in the second trimester,” said Dr. Adi Davidov, associate chair and director of obstetrics and gynecology at Staten Island University Hospital in Staten Island, N.Y.

Pregnancy weight gain chart: What to expect

The Mayo Clinic says minimal weight gain is typically needed in the first trimester, which can be a relief if you're dealing with morning sickness.

If you begin at a healthy weight, your aim is to gain 1 to 4 pounds (0.5 to 1.8 kilograms) in the initial months of pregnancy. There's no need for extra calories, just a nutritious diet.

Guidelines for subsequent trimesters, particularly for women who were underweight or who started at a healthy weight, emphasize consistent weight gain. Around 1 pound (0.5 kilogram) per week is expected until delivery. Consuming 300 calories daily -- equivalent to half a sandwich and skim milk -- can support this objective.

If you're overweight, the advice translates to about one-half pound (0.2 kilograms) weekly during the later trimesters. You can accomplish this by including low-fat milk, an ounce of cheese and a serving of fresh fruit in your diet.

The American Pregnancy Association breaks down anticipated weight gain by trimester as follows:

  • First trimester: 1-4.5 pounds

  • Second trimester: 1-2 pounds per week

  • Third trimester: 1-2 pounds per week

How much weight should you gain during pregnancy?

Though weight gain can vary from individual to individual, the U.S. Centers for Disease Control and Prevention more specifically states that the weight gain you should aim for during pregnancy depends on your body mass index (BMI) before becoming pregnant. BMI is an estimate of body fat based on weight and height.

“For patients with normal BMI, the recommended total weight gain during pregnancy is 25 to 35 pounds," Davidov said. Women with elevated BMI should gain less, about 20 to 25 pounds. Women with low BMI should gain more weight, about 35 to 45 pounds.

Though guidance can vary slightly from provider to provider, here are some basic guidelines from the CDC:

  • If before pregnancy you were underweight with a BMI below 18.5, you should gain 28 to 40 pounds.

  • If before pregnancy you were a normal weight with a BMI from 18.5 to 24.9, you should gain 25 to 35 pounds.

  • If before pregnancy you were overweight with a BMI from 25.0 to 29.9, you should gain 15 to 25 pounds.

  • If prior to pregnancy you were obese with a BMI of 30.0 or more, limit your gain to between 11 and 20 pounds.

If you are expecting multiples, your weight gain expectations will be different, of course.

"For women who have a normal BMI, both excessive weight gain as well as minimal weight gain is considered unhealthy. The exact numbers are not well established, but I usually tell my patients that gaining over 50 pounds or less than 10 pounds is unhealthy," Davidov said.

Excess weight gain typically happens from increased food intake and a sedentary lifestyle, he said. The Cleveland Clinic emphasizes that there is a greater risk of gestational diabetes if extra pounds come early in pregnancy. Gestational diabetes increases the risk that you will:

  • Need a cesarean section delivery due to a larger baby.

  • Experience hypoglycemia (reduced blood sugar levels).

  • Develop preeclampsia, a dangerous form of high blood pressure during pregnancy.

  • Have higher odds for developing type 2 diabetes in the future.

Focus on a healthy weight gain during pregnancy

Pregnancy is not the appropriate time for shedding pounds. Focus instead on a healthy weight gain.

Remember, the average weight gain during pregnancy varies based on factors like your BMI and overall health. Striving for proper prenatal care, nutrition and regular checkups with your ob-gyn is vital to ensure the well-being of both you and your baby.

Be sure to prioritize your health and trust your health care provider's guidance throughout your pregnancy.


Adi Davidov, MD, associate chair and director of obstetrics and gynecology, Staten Island University Hospital, Staten Island, N.Y.

Nemours Kids Health: A Week-by-Week Pregnancy Calendar

U.S. Centers for Disease Control and Prevention: Weight Gain During Pregnancy

Mayo Clinic: Pregnancy Week by Week

American Pregnancy Association: Pregnancy Weight Gain

Cleveland Clinic: Weight Gain During Pregnancy: How Much Is Too Much?

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