How much weight should I gain?
Most obstetricians and other health care professionals agree that a weight gain of about 11 kg to 16 kg (25 lb–35 lb) is optimal during pregnancy for most women of average weight and height.

If your normal weight before pregnancy was low, or if you are an adolescent (19 years of age or younger), you may need to gain more weight. If you are expecting twins, you will also need to gain more weight than is typical.

If your normal weight before pregnancy was high, you need not gain as much weight. Because every calorie counts, every attempt should be made to eat healthy, nutritious foods and to avoid dieting.

Check with your doctor to see how great a weight gain is optimal for you. Remember, your health care professional is the best source of information regarding your specific needs.

Recommended weight gains during pregnancy

Why does weight gain matter so much?
Maternal weight gain can significally affect birthweight. Appropriate weight gain is therefore important, because underweight or overweight babies may have difficulties.

An underweight baby (<3 kg [6.6 lb]) may develop problems associated with low birthweight. An overly large baby (>4 kg [8.8 lb]) may complicate labor and delivery.

Your health care professional will check your weight at every visit to ensure that your weight gain is appropriate. Monitoring your weight is a way of checking to see that your baby is receiving adequate nutrition.

Where does all of the weight go?
Your growing fetus is responsible for less than half of the weight you gain during pregnancy. Weight gain also occurs because of changes in your body tissues, fluids, blood, and stores of body fat.

Composition of weight gain in pregnancy
Most weight gain occurs in the last 2 trimesters. Most women gain 1 to 2 kg (2.2–4.4 lb) in the first trimester, followed by a steady increase of approximately 400 g (0.9 lb) per week to 10 lb at 20 weeks, 19 lb at 30 weeks, and 27 lb at term.

How will I lose all of this weight after my baby arrives?
You may worry about gaining weight during pregnancy because of fears that excess weight will linger after you deliver. However, studies show that on average about 4 kg (8.8 lb) remains immediately after birth, and only 2 kg (4.4 lb) remains 6 weeks after your baby’s birth.

If you follow your health care professional's recommendation for weight gain, chances are that all gained weight will be lost within 8 months.