How Much Weight Should I Gain During My Pregnancy in the First Trimester?

Medically Reviewed on 9/30/2022

Why do you gain weight during pregnancy?

Weight gain during pregnancy supports the developing baby. You should gain less than five pounds during the first trimester of your pregnancy.
Weight gain during pregnancy supports the developing baby. You should gain less than five pounds during the first trimester of your pregnancy.

Your body undergoes many changes during the nine months of pregnancy. During your pregnancy how much weight gain in the first trimester is appropriate?

‌Your weight gain during pregnancy helps support your developing baby. Your body has to:

  • Grow a placenta 
  • Produce amniotic fluid
  • Increase fat stores
  • Generate more blood
  • Increase the size of your uterus and breasts

What's a healthy weight gain during your first trimester?

During the first trimester, most women don’t usually gain much weight. Your baby is still tiny. Weight gain in your first trimester should be less than 5 pounds in total.

In the first trimester, many do not gain weight and may even lose weight. An estimated 70% to 80% of pregnant women experience vomiting and nausea, mostly in the first trimester.

Nausea and vomiting are known as “morning sickness," but can happen any time of the day. Morning sickness tends to start before your ninth week of pregnancy and goes away by your 14th week. For some women, vomiting and nausea can last for months. In a few rare cases, it can last throughout the pregnancy.

Nutrition in your first trimester

When you’re pregnant, people may advise you to have bigger portions or eat more, because you’re “eating for two”. That’s a common misconception. Your baby’s nutrition depends on what you eat but you don’t need to eat twice the amount during pregnancy.

In your first trimester, you don’t need to increase your calorie intake. In your first trimester, you should:

  • Eat a balanced diet
  • Make sure you get enough protein (70 to 80 grams a day)
  • Drink enough water
  • Take a prenatal vitamin

You may have pregnancy cravings in your first trimester. These may be caused by:

  • Hormonal changes
  • Lack of the right nutrients
  • Heightened sense of taste and smell. 

It’s ok to give in to your cravings sometimes. But do so in moderation, or you may gain too much.

Why it's important to gain the recommended amount of weight during pregnancy

Studies have found only about 32% of pregnant women gain the recommended amount of weight. About 48% put on too much and 21% didn’t put on enough.

Putting on too much weight during pregnancy can affect your health and that of your baby. You’re more likely to have a bigger, heavier baby. This can make it harder for you to have a natural delivery. You may need a Cesarean section. 

Too much pregnancy weight also increases your risk of:

Not gaining enough weight may not be safe for your baby. Your baby may be more likely to be born too early or weigh too little at birth.

A baby with a low birth weight may have problems with:

  • Vision and hearing
  • Lung development and breathing
  • Intestinal tract
  • Future developmental delays. 


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Recommended total weight gain during pregnancy

Talk to your doctor to determine the right weight gain for you. The total amount of weight you should gain depends on several factors:

  • Your pre-pregnancy weight
  • Your body mass index (BMI)
  • If you’re having twins or multiples.

The general guidelines for weight gain during pregnancy are:

  • If your BMI is under 18.5: gain between 28 to 40 pounds (about 13 to 18 kilograms).
  • If your BMI is between 18.5 to 24.9: gain between 25 to 35 pounds (about 11 to 16 kilograms)
  • If your BMI is between 25.0 to 29.9: gain between 15 to 25 pounds (about 7 to 11 kilograms)
  • If your BMI is 30 or more: gain between 11 to 20 pounds (about 5 to 9 kilograms).

For women expecting twins, weight gain recommendations are:

  • BMI under 18.5: gain between 50 to 62 pounds (about 23 to 28 kilograms).
  • BMI between 18.5 to 24.9: gain between 37 to 54 pounds (about 17 to 25 kilograms).
  • BMI between 25.0 to 29.9: gain between 31 to 50 pounds (about 14 to 23 kilograms).
  • BMI 30 or more: gain between 25 to 42 pounds (about 11 to 19 kilograms). 

When to see your doctor

You should see your doctor if:

  • Your nausea and vomiting are causing concern and affecting your life.
  • You’re losing or gaining a lot of weight in the first trimester.
  • You’re having cravings for things like nonfood substances like dirt, laundry starch, or crayons. This may be because you lack iron or zinc.

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Medically Reviewed on 9/30/2022

The American College of Obstetricians and Gynecologists: "Morning Sickness: Nausea and Vomiting of Pregnancy."

Centers for Disease Control and Prevention: "About Adult BMI," "Weight Gain During Pregnancy."

Gastroenterology Clinics of North America: "Nausea and Vomiting of Pregnancy." "Pregnancy and birth: Weight gain in pregnancy."

Intermountain Healthcare: "Why Pregnancy Can Make You Have Weird Cravings."

JAMA: "Babies With Low Birth Weight."

The Journal of Clinical Investigation: "Time to change weight gain recommendations for pregnant women with obesity."

The Ohio State University Wexner Medical Center: "What is normal weight gain during pregnancy?"

University of Missouri Health Care: "'Eating for Two' — A Quick Guide to Nutrition During Pregnancy."