September 12, 2014
DEAR DOCTOR K:
I am pregnant, and my doctor says that I’m gaining too much weight. I trust the doctor, but I’ve heard that it’s normal to gain weight during pregnancy. How much weight should a woman gain?
DEAR READER:
It’s natural for a woman’s appetite to increase during pregnancy. This is nature’s way of making sure that she eats enough for herself and her growing baby. All women should gain weight during pregnancy, while eating healthfully and sensibly. But too much weight gain isn’t good for a woman or her baby.
A woman of average weight should gain between 25 to 35 pounds during pregnancy. Ideally, a woman should gain 3 to 8 pounds in the first three months of pregnancy and three-quarters to 1 pound a week after that.
Most women of childbearing age who are moderately active require 2,000-2,200 calories a day before they get pregnant. They generally need only 300 additional calories per day after they become pregnant to achieve their target weight gain.
If a woman is underweight when she becomes pregnant, her doctor may encourage her to gain as much as 40 pounds. A woman who is overweight when she becomes pregnant should aim to gain between 15 and 25 pounds.
A good way to get needed nutrition and calories without gaining too much weight is to eat healthy snacks during the day. Fruits and vegetables, and cheese or nuts (in limited amounts) are nutritious choices.
A newborn baby generally weighs between 7.5 and 8.5 pounds. So what accounts for the remainder of weight gain? The majority of additional weight goes toward an increase in blood and body fluids and an increase in the mother’s fat stores. In addition, extra weight comes from breast enlargement, uterine weight gain, amniotic fluid and the placenta. Here’s a detailed breakdown:
| Typical Breakdown of Pregnancy Weight Gain | |
| Baby | 7.5 to 8.5 pounds at birth |
| Breast enlargement | 3 pounds |
| Placenta | 1 to 2 pounds |
| Blood and body fluid increase | 4 to 8 pounds |
| Amniotic fluid | 2 to 3 pounds |
| Uterine weight gain | 2 to 3 pounds |
| Maternal fat stores | 5 to 8 pounds |
| Total weight gain | 24.5 to 35.5 pounds |
Babies born to obese women or those who gain too much weight during pregnancy are more likely to be born with problems such as neural tube defects. This may be, in part, because obesity makes it more difficult to detect abnormalities during prenatal ultrasound tests. Women who gain too much weight during pregnancy are also more likely to give birth to heavier babies. These babies are more likely to be obese as children and adolescents.
While the risks to the baby when the pregnant mother is obese are small, they are real. If you are early in your pregnancy, you’ve got plenty of time to make corrections to your diet.