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Weight gain and pregnancy

​​​​​​​Weight gain is a normal and important part of pregnancy.

It is common to have feelings about body changes in pregnancy. These feelings could make discussions about weight gain uncomfortable.

During pregnancy, focus on eating well, being active, and getting rest. This is good for you and your baby, no matter how your weight changes.

Why weight gain is important

The weight you gain during pregnancy helps to support your growing baby. It goes toward your baby’s growing body, building a placenta, new blood and fluids, breast tissue, and more.

Gaining the amount of weight that is right for your body helps your baby be born at a healthy size and time. It also lowers the risk of health issues for you and your baby.

Recommended weight gain

The recommended amount of weight gain during pregnancy depends on your body mass index (BMI) before pregnancy.

To find out your pre-pregnancy BMI you can do one of the following:

The table below helps you know how much weight gain is recommended for you during pregnancy. These numbers assume you gain about 0.5 to 2 kilograms (kg)—around 1 to 4.5 pounds (lb.)—in your first trimester. Most of your weight gain happens in your second and third trimesters.​

​​​Pre-pregnancy BMIRecommended total weight gain for pregnancy* Average weekly weight gain in 2nd and 3rd trimesters*
less than 18.512.5 to 18 kg
(28 to 40 lb.)
0.5 kg (1 lb.)
each week
​18.5 to 24.911.5 to 16 kg
(25 to 35 lb.)​
0.4 kg (1 lb.)
each week​
25.0 to 29.9​7 to 11.5 kg
(15 to 25 lb.)​
0.3 kg (0.6 lb.)
each week
30 and over​5 to 9 kg
(11 to 20 lb.)
0.2 kg (0.5 lb.)
each week

*Health Canada 2010 Gestational Weight Gain Guidelines

Every pregnancy is different. You may gain more or less than the recommendations provided. Talk to your healthcare provider if you have questions or concerns about your weight gain during pregnancy.

​Weight gain with twins, triplets, and more

Early weight gain is important when you’re pregnant with twins, triplets, or more. Ask your healthcare provider early in your pregnancy (first trimester if possible) for a referral to a registered dietitian for support with weight gain.

If you’re pregnant with twins, the following weight gain is recommended:

​​​Pre-pregnant BMI​​Total weight gain for a twin pregnancy
​18.5 to 24.917 to 25 kg
(37 to 54 lb.)
25.0 to 29.9​14 to 23 kg
(31 to 50 lb.)​
​30 and over​11 to 19 kg
(25 to 42 lb.)

If your pre-pregnant BMI is less than 18.5 or you are pregnant with triplets or more, talk to your healthcare provider about how much weight gain is recommended for you.

Current as of: May 17, 2023

Author: Healthy Children and Families, Alberta Health Services