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Obesity and Pregnancy

Overview

How might a high BMI affect your pregnancy?

Body Mass Index (BMI) is a measure based on your weight (kg) divided by your height (m)2. A high BMI can increase health risks during pregnancy. A BMI of 30.0 or more is classified as obese.

The basics of prenatal care are the same for everyone, regardless of size. You'll get what you need to have a healthy baby.

But your size can make a difference in a few things. You and your doctor or midwife will have to watch your pregnancy weight. Your weight may affect your labour and delivery.

You may have some extra doctor or midwife visits and tests. And you may have some tests earlier in your pregnancy. You'll need to pay close attention to things like blood pressure and the chance of getting gestational diabetes. (This is a type of diabetes that sometimes happens during pregnancy.) And close attention will be given to your developing baby.

Work with your doctor or midwife to get the care you need. Go to all your doctor or midwife visits, and follow your doctor's or midwife's advice about what to do and what to avoid during pregnancy.

How much weight gain is healthy during pregnancy?

If you have a BMI of 30 or more, experts recommend that you gain between 5 and 9 kilograms (11 and 20 pounds).footnote 1 Your doctor or midwife will work with you to set a weight goal that's right for you. In some cases, your doctor or midwife may recommend that you not gain any weight.

What problems can happen?

If you have a BMI of 30 or more during pregnancy, you have greater risks for:

How much extra food do you need to eat?

Although you may joke that you're "eating for two" during pregnancy, you don't need to eat twice as much food. How much you can eat depends on:

  • Your height.
  • How much you weigh when you get pregnant.
  • How active you are.
  • If you're carrying more than one fetus (multiple pregnancy).

In the first trimester, you'll probably need the same amount of calories as you did before you were pregnant. In general, in your second trimester, you need to eat about 340 extra calories a day.footnote 2 In your third trimester, you need to eat about 450 extra calories a day.

What can you do to have a healthy pregnancy?

The best things you can do for you and your baby are to eat healthy foods, get regular exercise, avoid alcohol and smoking, and go to your doctor or midwife visits.

  • Eat a variety of foods from Canada's Food Guide. Make sure to get enough calcium and folic acid. Experts recommend taking a daily multivitamin with folic acid during pregnancy. footnote 3
  • You may want to work with a dietitian to help you plan healthy meals to get the right amount of calories for you.
  • If you didn't exercise much before you got pregnant, talk to your doctor or midwife about how you can slowly get more active. Your doctor or midwife may want to set up an exercise program with you.

References

Citations

  1. Public Health Agency of Canada. (2021). Your guide to a healthy pregnancy. Government of Canada. https://www.canada.ca/en/public-health/services/health-promotion/healthy-pregnancy/healthy-pregnancy-guide.html. Accessed August 16, 2021.
  2. Kaiser LL, Campbell CG (2014). Practice paper: Nutrition and lifestyle for a healthy pregnancy outcome. Journal of the Academy of Nutrition and Dietetics, 114(7): 1099-1103. http://www.eatrightpro.org/resource/practice/position-and-practice-papers/practice-papers/practice-paper-nutrition-and-lifestyle-for-a-healthy-pregnancy-outcome. Accessed November 16, 2017.
  3. Wilson RD, O'Connor DL (2022). Guideline No. 427: Folic acid and multivitamin supplementation for prevention of folic acid-sensitive congenital anomalies. Journal of Obstetrics and Gynaecology Canada, 44(6): 707–719. Accessed January 5, 2023. Erratum in Journal of Obstetrics and Gynaecology Canada, 44(10): 1114.

Credits

Adaptation Date: 05/27/2024

Adapted By: Alberta Health Services

Adaptation Reviewed By: Alberta Health Services

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