From promoting your baby's development to paving the way for post-pregnancy weight loss, here's why pregnancy weight gain matters.

By Mayo Clinic Staff

Like it or not, eating for two isn't a license to eat twice as much as usual. Use healthy lifestyle habits to manage your pregnancy weight gain, support your baby's health and make it easier to shed the extra pounds after delivery.

There's no one-size-fits-all approach to pregnancy weight gain. Appropriate weight gain for you depends on various factors, including your pre-pregnancy weight and body mass index (BMI). Your health and your baby's health also play a role. Work with your health care provider to determine what's right for you.

Consider these general guidelines for pregnancy weight gain:

Pre-pregnancy weight Recommended weight gain
Underweight (BMI < 18.5) 28 to 40 lbs. (about 13 to 18 kg)
Normal weight (BMI 18.5 to 24.9) 25 to 35 lbs. (about 11 to 16 kg)
Overweight (BMI 25 to 29.9) 15 to 25 lbs. (about 7 to 11 kg)
Obese (BMI 30 or more) 11 to 20 lbs. (about 5 to 9 kg)

If you're carrying twins or other multiples, you'll likely need to gain more weight. Again, work with your health care provider to determine what's right for you.

Consider these general guidelines for pregnancy weight gain if you're carrying twins:

Pre-pregnancy weight Recommended weight gain
Normal weight (BMI 18.5 to 24.9) 37 to 54 lbs. (about 17 to 25 kg)
Overweight (BMI 25 to 29.9) 31 to 50 lbs. (about 14 to 23 kg)
Obese (BMI 30 or more) 25 to 42 lbs. (about 11 to 19 kg)

Being overweight before pregnancy increases the risk of various pregnancy complications, including gestational diabetes, high blood pressure disorders of pregnancy, including preeclampsia, and the need for a C-section. Although a certain amount of pregnancy weight gain is recommended for women who are overweight or obese before pregnancy, some research suggests that women who are obese can safely gain less weight than the guidelines recommend. Further study is needed.

Work with your health care provider to determine what's best in your case and to manage your weight throughout pregnancy.

If you're underweight before pregnancy, it's essential to gain a reasonable amount of weight while you're pregnant. Without the extra weight, your baby might be born early (premature birth) or smaller than expected.

Gaining too much weight during pregnancy can increase your baby's risk of health problems, such as being born significantly larger than average (fetal macrosomia), and complications at birth, such as the baby's shoulder becoming stuck after the head is delivered (shoulder dystocia). Excessive weight gain during pregnancy can also increase your risk of postpartum weight retention.

Let's say your baby weighs in at 7 or 8 pounds (about 3 to 3.6 kilograms). That accounts for some of your pregnancy weight gain. What about the rest? Here's a sample breakdown:

  • Larger breasts: 1 to 3 pounds (about 0.5 to 1.4 kilogram)
  • Larger uterus: 2 pounds (about 0.9 kilogram)
  • Placenta: 1 1/2 pounds (about 0.7 kilogram)
  • Amniotic fluid: 2 pounds (about 0.9 kilogram)
  • Increased blood volume: 3 to 4 pounds (about 1.4 to 1.8 kilograms)
  • Increased fluid volume: 2 to 3 pounds (about 0.9 to 1.4 kilograms)
  • Fat stores: 6 to 8 pounds (about 2.7 to 3.6 kilograms)

In the first trimester, most women don't need to gain much weight — which is good news if you're struggling with morning sickness.

If you start out at a healthy or normal weight, you need to gain only about 1 to 4 pounds (0.5 to 1.8 kilograms) in the first few months of pregnancy. You can do this by eating a healthy diet — no extra calories are necessary.

Steady weight gain is more important in the second and third trimesters — especially if you start out at a healthy weight or you're underweight. According to the guidelines, you'll gain about 1 pound (0.5 kilogram) a week until delivery. An extra 300 calories a day — half a sandwich and a glass of skim milk — might be enough to help you meet this goal. For overweight and obese women, the guidelines translate to a weight gain of about 1/2 pound (0.2 kilogram) a week in the second and third trimesters. Try adding a glass of low-fat milk or an ounce of cheese and a serving of fresh fruit to your diet.

Your health care provider will keep a close eye on your weight. Do your part by eating a healthy diet and keeping your prenatal appointments. To keep your pregnancy weight gain on target, your health care provider might offer suggestions for boosting calories or scaling back as needed.

Feb. 15, 2017