Eating for Two: Weight Influences on Pregnancy

Weight gain during pregnancy helps your baby grow. Gaining weight at a steady rate within recommended boundaries can also lower your chances of having hemorrhoids, varicose veins, stretch marks, backache, fatigue, indigestion, and shortness of breath during pregnancy.

Why is weight gain important during pregnancy?

The extra weight you gain during pregnancy provides nourishment to your developing baby and is also stored for breastfeeding your baby after delivery.

Where does all the extra weight go?

Here is an approximate breakdown of your weight gain:

  • Baby = 7 pounds
  • Placenta = 1-2 pounds
  • Amniotic fluid = 2 pounds
  • Uterine enlargement = 2 pounds
  • Maternal breast tissue = 2 pounds
  • Maternal blood flow = 2 pounds
  • Fluids in maternal tissue = 4 pounds
  • Maternal fat stores = 7 pounds

How much total weight should I gain?

The amount of weight you should gain depends on your weight before pregnancy. You should gain:

  • 25-35 pounds: If you were a healthy weight before pregnancy.
  • 28-49 pounds: If you were underweight before pregnancy.
  • 15-25 pounds: If you were overweight before pregnancy.
  • :11-20 pounds If you were obese before pregnancy.

At what rate should I gain weight during my pregnancy?

How much you should gain depends on your weight before you were pregnant and how far along you are in your pregnancy.

  • Healthy Weight Before Pregnancy
    • 3-4 pounds during the first trimester.
    • About a pound a week to equal 12-14 pounds during the second trimester.
    • About a pound a week during the 7th and 8th months
    • About a pound or two a week during the 9th month
  • Underweight Before Pregnancy
    • 5-6 pounds or more in your first trimester. This also can depend on how underweight you were before pregnancy, if you had an eating disorder and what your doctor's recommendation is.
    • 1-2 pounds a week during the last six months.
  • Overweight Before Pregnancy
    • Very little weight in the first three months, 1-2 pounds.
    • A little less than a pound a week during the last six months.

The goal is to keep weight gain as steady as possible because your baby requires a daily supply of nutrients throughout your pregnancy that comes from what you eat. It is okay for your weight gain to fluctuate a little from week to week. However the following are some red flags to be aware of:

  • Gaining more than 3 pounds in any one week during your second trimester
  • If you gain more than two pounds in any one week during your third trimester.
  • Not gaining weight for more than two weeks in a row anytime during the 4th through 8th months.
  • If you find yourself gaining more weight then you anticipated and you have been trying to stick with a realistic meal plan without taking necessary nutrients away from the baby.
  • If you experience any of these, it is probably best to contact your health care provider.

What if I am carrying twins?

For women giving birth to twins: normal-weight women should gain 37 to 54 pounds; overweight women should gain 31 to 50 pounds; and obese women should gain 25 to 42 pounds. Your appropriate weight gain should be monitored by your healthcare provider.

Does being underweight pose any risks to me or my baby?

Due to morning sickness, many women have trouble gaining weight in the first trimester and worry about what effects this has on their baby's development. Some women loose a little weight in the beginning of their pregnancy. Fortunately, at this time the baby does not need as many calories and nutrients as later in pregnancy.

It is important to gain weight at a steady pace throughout pregnancy. If a woman does not gain weight throughout pregnancy, complications such as a low-birth weight infant or premature delivery could occur. Babies who are born to mothers who do not gain more than 20 pounds are often considered small for gestational age (SGA) meaning they may have been malnourished during pregnancy, and tend to suffer growth restriction in the uterus. This condition puts the baby at risk for a variety of problems later in life, including eating disorders.