Weight gain during pregnancy

Women who gain the recommended amount of weight during pregnancy have fewer complications.

How much weight should I gain during pregnancy?

Weight gain during pregnancy supports the growth of your baby and the placenta, as well as changes in your body (such as an increased volume of blood and fluid, larger breast size, and some storage of fat). Evidence shows that women who gain the recommended amount of weight during pregnancy have fewer complications, such as caesarean section, gestational hypertension, and low or high birth weight.

The following guidelines may be useful for you, but keep in mind that weight gain will be different for everybody. Speak with your health-care professional if you are concerned that you are gaining too much or too little weight.

BMI before pregnancy Recommended weight gain
Less than 18.5 12.5 to 18 kg (28 to 40 lb)
Between 18.5 and 24.9 11.5 to 16 kg (25 to 35 lb)
Between 25 and 29.9 7 to 11.5 kg (15 to 25 lb)
More than 30 At least 7 kg (15 lb)
Twin pregnancies 16 to 20.5 kg (35 to 45 lb)


What is BMI?

Body Mass Index (BMI) is used to estimate a healthy weight range for a person over 18 years of age, based on his or her height. Keep in mind that this measurement does not take into account factors such as genetics or bone structure, which will also influence a person’s weight. If you have concerns about your weight, speak to your health-care professional.

How do I calculate my BMI?

To calculate your BMI, and to see ranges for your optimal BMI, visit Health Canada’s BMI resource at the bottom of this page. You can also use this formula:

BMI = weight (kg) / height (m2)

Example: You are 160 cm tall and weigh 65 kg.

Body Mass Index

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