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How much weight should I gain while pregnant?

Many factors can affect your average weight gain during pregnancy

Profile picture of Jessica Render
by Jessica Render ConsumerAffairs Research Team
expecting couple holding hands

With all of the conflicting cultural messages, weight gain can be socially fraught no matter how healthy your body is. But who gets a free pass? You do, pregnant person! Weight gain is a natural and healthy part of pregnancy.

It’s easy enough to gain weight to support this beautiful embryo through all of its developmental stages for months until the baby’s birth, right? Sometimes it’s easier said than done.

So, just how much weight are you actually expected to gain over these 40 weeks?

Average weight gain during pregnancy

Gaining either too much or not enough weight isn’t healthy for you or your baby. According to the U.S. Centers for Disease Control, gaining too much weight is associated with gestational diabetes, a large fetus that could require delivery by C-section and greater risk of childhood obesity.

A too-low pregnancy weight isn’t as much cause for concern in the first trimester, as some women’s nausea and/or food aversions can result in unintended weight loss early on. In later weeks, however, the potential consequences of not gaining a sufficient amount include a preterm delivery and a newborn with a low birth weight. Premature babies and those with low birth weights are at an increased risk for illness, developmental delays and difficulty with starting to breastfeed.

If you wonder where in this range you fall, check the CDC’s guidelines in the table below.

Target weight gain in pregnancy

BMI before pregnancyHealthy pregnancy weight gain
Underweight (18.5 or less)28 to 40 pounds
Normal weight (18.5 to 24.9)25 to 35 pounds
Overweight (25 to 29.9)15 to 25 pounds
Obese (30 or more)11 to 20 pounds

If you don’t already know your body mass index (BMI), a figure based on your height and weight, you can find it by using the calculator provided by the National Heart, Lung and Blood Institute.

Pregnancy weight gain by trimester

If your pre-pregnancy BMI was within the normal range, you should expect to gain about 25 to 35 pounds over 40 weeks. Those pounds obviously won’t come on all at once. So, when will you see the number on the scale start to go up?

First trimester weight gain: During the first trimester, it’s unlikely you’ll see much of a change in your weight. If you’re on track to gain between 1 and 4.5 pounds by the end of week 12 of your pregnancy, you’re within the normal range.

Second trimester weight gain: From week 13 to the end of week 26, you’d be in the minority if you didn’t notice a substantial change in your appearance. Through your second trimester, you’re within the normal range if you gradually gain about 14 pounds — around 1 to 2 pounds or so each week, although your weight might plateau one week and rise the next. Most of this weight is due to your increased fluid and blood volume.

Third trimester weight gain: In the third trimester, you can expect to continue gaining weight — about 1 to 2 pounds a week — though you’ll probably add weight less steadily than you did in the second trimester. A lot of the weight added in the final weeks goes straight onto your baby.

What accounts for this weight gain? Here’s how a 30-pound weight gain breaks down, on average, in pregnancy:

  • 7.5 pounds for your full-term newborn
  • 7 pounds for maternal stores of protein, fat and other nutrients
  • 4 pounds for increased fluid volume
  • 4 pounds for increased blood volume
  • 2 pounds of additional breast tissue
  • 2 pounds of additional uterine weight
  • 2 pounds of amniotic fluid
  • 1.5 pounds of placenta

Bottom line

Remember, every pregnancy and every person is different. If your weight isn’t within the range considered normal or you have other concerns about gaining weight, speak with your obstetrician before you fret too much. They may offer a different weight gain regimen better suited to you.

Even if you're secure with your body, the weight you’re expected to gain for a healthy pregnancy — anywhere from 11 to 40 pounds — isn’t always easy to accept. Regardless of how much weight you gain, it’s common to feel conspicuous and uncomfortable at times with your body. If you have one of those days, remind yourself that more than half of the weight gained in pregnancy is your baby and the fluids and tissues that support his or her development. They will come out of you on the day of your delivery or shortly thereafter. So, listen to your body — it knows what it’s doing!

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Profile picture of Jessica Render
by Jessica Render ConsumerAffairs Research Team

As a member of the ConsumerAffairs research team, Jessica Render is dedicated to providing well-researched, valuable content designed to help consumers make informed purchase decisions they can feel confident making. She holds a degree in journalism from Oral Roberts University.