Weight gain during pregnancy

Does it really matter how much weight I gain during my pregnancy?

Gaining weight during pregnancy is, of course, inevitable. It isn’t just the baby that contributes to weight gain. Your placenta, increased blood volume, larger breasts, and fat stores to support breastfeeding, also contribute. How much you gain is quite important, as it can affect both you and your baby. There are targets for weight gain that reflect the best outcomes for both of you. Gaining weight within the recommended targets reduces your risk of gestational diabetes, preterm birth, and having a large baby, compared to gaining too much. Your baby will also be less likely to be overweight later in life. Gaining too little weight can also cause problems, with greater risk of low birth weight, preterm birth, and difficulty breastfeeding.

How much weight should I gain?

The ideal amount of weight gain during your pregnancy depends on your BMI prior to pregnancy. Use this table to get an idea of the range of weight gain that is recommended for your BMI. Or try this pregnancy weight gain calculator.

If you are struggling to keep your weight gain in the recommended range, talk to your health care provider. There are lots of great strategies to help you alter your dietary intake or your physical activity. It is not recommended that you try to lose weight during pregnancy, even if you are obese.

Pre-pregnancy BMI

Average weekly weight gain in 2nd and 3rd trimesters

Recommended total weight gain






less than 18.5





18.5 to 24.9



11.5 to 16

25 to 35

25.0 to 29.9



7 to 11.5

15 to 25

Greater than 30



5 to 9

11 to 20