Nutrition and Weight Gain During Pregnancy

Topic Overview

A balanced, nutritious diet during pregnancy is important to maintain your health and nourish your fetus. Be sure to increase your daily caloric intake by 300 calories after you become pregnant.

The average woman needs 2,200 calories a day and 2,500 when she is pregnant. If she is carrying twins, her need increases to 3,500 calories, and for triplets or more, she needs 4,500 calories.1 Talk to your doctor or a dietitian about your daily calorie needs because your needs depend on your height, weight, and activity level.

Your doctor may give you a nutrition plan to follow throughout pregnancy and while breast-feeding. You may also receive a prescription for a vitamin and mineral supplement or a list of recommended nonprescription supplements.

Check out the federal Women, Infants, and Children (WIC) nutritional program for helpful information ( If your resources are limited, you may qualify for WIC financial assistance for basic healthy foods during and after your pregnancy.

Folic acid

Folic acid is a B vitamin. Taking folic acid before and during early pregnancy reduces the chance of having a baby with a neural tube defect or other birth defects.

  • Women of childbearing age should get 0.4 mg (400 mcg) of folic acid from fortified food, supplements, or a mix of food plus supplements. This amount is found in most once-a-day multivitamins.2
  • Women who are pregnant with twins or more should take 1 mg (1000 mcg) of folic acid daily. Folic acid is available in this strength by prescription only.3
  • Women who have a family history of neural tube defects, who have had a baby with a neural tube defect, or who are on medicines for seizures should take additional folic acid: a daily dosage of 4 mg (4000 mcg) of folic acid is recommended. Do not try to reach this amount of folic acid by taking more multivitamins because you could get too much of the other substances that are in the multivitamin.2


You will need twice as much iron in your second and third trimesters as you did before pregnancy. This extra iron supports the extra blood in your system and helps with the growth of the placenta and the fetus. Wait until your second trimester to start taking iron. Your iron requirements are slight during the first trimester of pregnancy, and taking iron supplements in the first trimester may aggravate morning sickness.

After the first trimester, take a daily supplement containing 30 mg of iron (most prenatal vitamins include iron). A woman with a multiple pregnancy is advised to take 60 mg to 100 mg of iron daily.3 Iron supplements can cause an upset stomach and constipation. Taking your iron at bedtime may decrease the chance of stomach upset. Your body absorbs iron best in small amounts when you eat it with vitamin C, so you may want to take your iron throughout the day.


Calcium is necessary for the development of the fetus's skeleton. You can get enough calcium in your diet by eating or drinking 4 servings from the dairy (milk) group each day. Good sources of calcium from nonmilk sources include:

  • Greens (such as mustard and turnip greens), bok choy, kale, and watercress.
  • Broccoli and cauliflower.
  • Tofu that is "calcium-set."
  • Corn tortillas made with lime.
  • Calcium-fortified orange juice.

Weight gain during pregnancy

The recommended weight gain for a woman of normal weight is 25 lb (11.3 kg) to 35 lb (15.9 kg). A gain of 30 lb (13.6 kg) usually consists of the following:

  • The baby weighs 7.5 lb (3.4 kg).
  • The placenta weighs 1.5 lb (0.7 kg).
  • The amniotic fluid weighs 2 lb (0.9 kg).
  • The uterus weighs 2 lb (0.9 kg).
  • Breast tissue weighs 2 lb (0.9 kg).
  • Excess blood and fluids weigh 8 lb (3.6 kg).
  • Fat weighs 7 lb (3.2 kg).

You can expect to gain more if you are carrying twins.

If you are overweight, your ideal goal is less than the average weight gain, 15 lb (6.8 kg) to 25 lb (11.3 kg). If you are underweight, it is best to gain 28 lb (12.7 kg) to 40 lb (18.1 kg).

Ideally, you will gain weight slowly over the entire pregnancy:

  • Up to 4 lb (1.8 kg) during the first trimester
  • 1 lb (0.5 kg) a week during the second and third trimesters

If you stop gaining weight for more than 2 weeks, or if you gain weight faster than these recommendations, consult your doctor.



  1. Newman RB, Rittenberg C (2008). Multiple gestation. In RS Gibbs et al., eds., Danforth's Obstetrics and Gynecology, 10th ed., pp. 220–245. Philadelphia: Lippincott Williams and Wilkins.
  2. American Academy of Pediatrics, American College of Obstetricians and Gynecologists (2007). Antepartum care. In Guidelines for Perinatal Care, 6th ed., pp. 83–137. Elk Grove Village, IL: American Academy of Pediatrics.
  3. Cunningham FG, et al. (2005). Multifetal gestation. In Williams Obstetrics, 22nd ed., pp. 911–948. New York: McGraw-Hill.


Author Sandy Jocoy, RN
Editor Kathleen M. Ariss, MS
Associate Editor Pat Truman, MATC
Primary Medical Reviewer Sarah Anne Marshall, MD - Family Medicine
Specialist Medical Reviewer Kirtly Jones, MD - Obstetrics and Gynecology
Last Updated November 28, 2008

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