Pregnancy Information Center

Information, Symptoms, Treatments and Resources


Your Pregnancy Weight Gain Guide


Learn how much to put on for your healthiest pregnancy and why it matters so much

By Natalie Gingerich Mackenzie

Weight gain may be the most obvious (and, for some, dreaded) aspect of pregnancy. But pregnancy weight gain isn’t the same thing as “getting fat,” and shouldn’t be labeled that way. To be healthy during pregnancy, you need to put on pounds. In fact, your body’s change in size and shape is an essential part of the complex process that allows you to grow a human being and carry it around inside you for 9 months.


Your Pregnant Body

The changes begin nearly as soon as your pregnancy hormones reveal those two little lines when you pee on the stick. Your breasts may start to swell and grow. Hormonal changes loosen your ligaments (tissue that connects bones or cartilage together), expanding the rib cage and making room for your uterus to transform from the size of an orange to the size of a watermelon. Eventually, your hips widen and your center of gravity shifts to balance your growing belly. 

The bundle of joy you take home at the end, weighing around 6 to 8 pounds, is just one piece of your pregnancy weight gain puzzle. The 30 pounds of average weight gain consist of baby’s pounds, plus: 

  • 8 pounds of extra blood and body fluids
  • 7 pounds of added fat and muscle throughout your body
  • 2 pounds of amniotic fluid for baby’s protection
  • 2 pounds for your growing breasts 
  • 2 pounds for your growing uterus
  • 1.5 pounds for the placenta to nourish baby 


Your Weight Gain Goal

So how do you know what’s the right amount of weight gain for you, and what’s too much or too little? The amount you need to gain is closely linked with your own pre-pregnancy weight. If you’re at a healthy weight when you get pregnant, your sweet spot is about 25 to 35 pounds. If you’re overweight, you’ll aim to gain less. Underweight or carrying multiples? You’ll try to gain more.

Not sure where you fall? Ask your doctor or midwife. And don’t assume no news is good news: Weight can be a difficult subject to discuss, but that doesn’t mean your provider doesn’t think it’s important. A study of doctors and midwives in the Journal of Women’s Health found that many were hesitant to bring up pregnancy weight gain for reasons as simple as being self-conscious about their own weight or not wanting to offend or worry their patients. 

Along with tracking your weight changes, your provider will monitor your baby’s growth throughout pregnancy to make sure things are on track. This chart is based on information from the US Office of Women’s Health, the same information the I’m Expecting app uses to calculate whether your weight is on track. 

Your pre-pregnancy weight

Total you should aim to gain

First trimester total weight gain

Second and third trimester weight gain per week

Underweight (BMI less than 18.5)

28-40 pounds

2.2-6.6 pounds

1.0-1.3 pounds

Healthy weight (BMI 18.5 to 24.9)

25-35 pounds

2.2-6.6 pounds

0.8-1.1 pounds

Overweight (BMI 25-29.9)

15-25 pounds

2.2-6.6 pounds

0.5-0.7 pounds

Obese (BMI over 30)

11-20 pounds

0.5-4.4 pounds

0.4-0.6 pounds


Why Weight Gain Matters

Putting on too much or too little can have negative effects for you and your baby. Here’s how:

 Gaining too much can:

  • Double your risk of giving birth to a large baby
  • Increase your chances of giving birth by C-section
  • Up your odds of having gestational diabetes
  • Boost your baby’s risk of growing up to be overweight or obese

Gaining too little can lead to:

  • Giving birth too early
  • Giving birth to a baby who’s too small
  • Having a baby with delayed development or heart or lung problems


Tracking your weight using the I’m Expecting app (for iOS and Android) goes a long way when it comes to helping you achieve a healthy weight during pregnancy. For three tips for staying on track, click here

Published on November 10, 2015. 

Natalie Gingerich Mackenzie is a health and fitness writer and editor, as well as a certified personal trainer through the American Council on Exercise. She regularly contributes to national magazines including Fitness, Shape and SELF, and is the author of Tone Every Inch.

IPG GutenbergUKltd/iStock/Thinkstock
Reviewed by Elisabeth Aron, MD, MPH, FACOG on October 30, 2015.
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