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Not Gaining Weight During Pregnancy? What’s Normal & What’s Not

Experts *weigh* in.

Originally Published: 

It only makes sense that being pregnant means packing on some extra pounds — your body is literally growing another human being. For most pregnant people, some weight gain isn’t just expected, it’s encouraged. But, for some, the number on the scale doesn’t really go up, and they might start to wonder if it’s normal to not gain weight during pregnancy, or if something could be wrong. When you hear some pregnant people talk about gaining 30, 50, or 100 pounds, meanwhile you’re pregnant but not gaining weight, it can be unnerving. Before you freak out, take a deep breath and remember that your weight during pregnancy — gain or or lack thereof — doesn’t always mean that something is wrong with the baby.

Is it normal to not gain weight during pregnancy?

Only about one-third (32%) of women gain the recommended amount of weight during pregnancy. Most women (48%) gain more than the recommendations, and some women (21%) gain less, per the Centers of Disease Control and Prevention (CDC). The amount of weight your doctor or health care professional will usually suggest that you gain during pregnancy depends on your body mass index (BMI). That means that it suggested average weight gain recommendations will varies from person to person. This makes it hard to say what is really “normal” and what isn’t, explains Dr. Mary Jacobson, M.D., OB-GYN and chief medical advisor for Alpha Medical. The reason obstetricians care about your the number on the scale — and might be concerned if you’re not gaining weight during pregnancy — is because gaining less than the recommended amount can be associated with birthing smaller babies, which can come with its own set of risks, like difficulty breastfeeding and increased risk of illness.

Still, sometimes it can be difficult for a pregnant woman to gain weight. Jacobson notes that the below reasons can contribute to no or very little weight gain during pregnancy:

  • Calorie restriction
  • Hyperemesis gravidarum, a condition that causes severe nausea and vomiting during pregnancy
  • Autoimmune disorders such as rheumatoid arthritis and systemic lupus erythematosus
  • Cancer

Keep in mind that weight gain doesn’t always happen during the first few weeks of pregnancy, especially if you’re experiencing a lot of nausea or morning sickness and having trouble keeping food down. If you’re not gaining weight in the first trimester of pregnancy, rest assured that you’re in good company. For many pregnant people, pregnancy weight gain doesn’t begin until the second trimester. In fact, some women with morning sickness will actually lose weight in the first trimester, Dr. Jill Purdie, M.D., OB-GYN and medical director at Northside Women’s Specialists in Atlanta, Georgia, tells Romper. The weight is often re-gained once the nausea and vomiting stops. If you’re struggling to maintain weight in the first trimester, don’t stress. Just be sure to drink plenty of water, reminds Purdie, because it is easy to become dehydrated when pregnant.


How much weight gain in pregnancy is considered normal?

There is no one ideal weight you should aspire to when you’re pregnant, as the “normal” amount varies for each person. “How much weight a person should gain in pregnancy is dependent on their body mass index,” explains Jacobson. “BMI is a measurement of body fat based on height and weight. It can be calculated using pounds and inches: BMI = (weight in pounds x 703) / (height in inches x height in inches). It is also dependent on if they have a singleton or multiple gestation (more than one fetus in utero) pregnancy.”

The Institute of Medicine offers a chart of expected weight gain during a single or twin pregnancy, which Jacobson recommends looking at and following. For a single pregnancy:

  • If before getting pregnant you had a BMI under 18.5, you should gain 28-40 pounds.
  • If before getting pregnant you had a BMI between 18.5 and 24.9, you should gain 25-35 pounds.
  • If before getting pregnant you had a BMI between 25 and 29.9, you should gain 15-25 pounds.
  • If before getting pregnant you had a BMI over 30, you should gain 11-20 pounds.

Remember, these are general recommendations. If you are not gaining weight during pregnancy so far, talk to your health care provider. If they aren’t concerned, then you likely don’t need to be either.

When to be concerned about your weight in pregnancy

Everyone’s body is different, which means that not everyone will gain the recommended amount of weight during pregnancy — and sometimes that’s totally fine. Sometimes, though, not gaining weight during pregnancy is cause for concern. Your medical provider will probably check your weight at each appointment. If they notice something they’re worried about, they will look into it. Or, if you’re worried, you should feel empowered to ask them for more information.

“If the size of your uterus, measured as fundal height from your pubic bone to the top of your uterus, is not progressively increasing after 20 weeks gestation, your obstetric clinician will recommend a ‘growth scan’ or abdominal ultrasound to measure different aspects of the fetus, like head circumference, abdominal circumference, and femur length, as well as pockets of amniotic fluid around the fetus in order to make a treatment plan,” Jacobson says.


How to gain weight with severe morning sickness

Again, it’s extremely normal to not gain much weight during the first trimester of pregnancy, and those who struggle with morning sickness may even lose weight. If you’re worried, though, try eating small, frequent meals. The food you do eat should be high in carbohydrates and low in fat. If you know certain foods make you feel more sick, avoid them at all costs. Eat foods with higher levels of protein and calories, like protein shakes or supplement shakes, advises Purdie.

Other popular nausea remedies for the first trimester include drinking ginger tea, acupressure devices like Sea-Bands, or a combination of vitamin B6 and Unisom at bedtime. Be sure to clear this — and any new medications — with your OB-GYN before trying them.


Dr. Mary Jacobson, M.D., OB-GYN and chief medical advisor for Alpha Medical

Dr. Jill Purdie, M.D., OB-GYN and medical director at Northside Women’s Specialists

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