Nutrition during pregnancy

During the second trimester, a pregnant woman should consume an additional 340 kcal/day above the nonpregnant energy requirement, and in the third....
Mahitab Hany, BS Pharm, PGDipClinPharm, PGDipClinNutrition

Overview

Nutrition in pregnancy can affect maternal health and infant size and well-being. Pregnant women should have nutrition counseling early in prenatal care and access to supplementary food programs if necessary.

  • Counseling should stress abstention from alcohol, smoking, and recreational drugs.
  • Caffeine and artificial sweeteners should be used only in small amounts (pregnant should limit their caffeine intake to no more than 200 mg/day, the equivalent of one 12-ounce cup of coffee).
  • Diet should contain the following foods: protein foods of animal and vegetable origin, milk and milk products, whole-grain cereals and breads, and fruits and vegetables especially green leafy vegetables.

Recommendations regarding weight gain in pregnancy should be based on maternal body mass index (BMI) preconceptionally or at the first prenatal visit. According to the National Academy of Medicine guidelines, total weight gain should be 11–16 kg (25–35 lbs) for normal weight women (BMI of 18.5–24.9) and 7–11 kg (15–25 lbs) for overweight women. For obese women (BMI of 30 or greater), weight gain should be limited to 5–9 kg (11–20 lbs). Excessive maternal weight gain has been associated with increased birth weight as well as postpartum retention of weight. Not gaining weight in pregnancy, conversely, has been associated with low birth weight. Nutrition counseling must be tailored to the individual patient.

Nutrition recommendations

Calorie (energy) intake

In general, women who were at a healthy weight before becoming pregnant need between 2200 calories and 2900 calories a day. The first trimester does not require any extra calories. During the second trimester, a pregnant woman should consume an additional 340 kcal/day above the nonpregnant energy requirement, and in the third trimester, the additional caloric requirement is 452 kcal/day.

Vitamins

The increased need for iron and folic acid should be met with foods as well as vitamin and mineral supplements. Megavitamins should not be taken in pregnancy, as they may result in fetal malformation or disturbed metabolism. However, a balanced prenatal supplement containing 30 mg of iron, 400 mcg (0.4 mg) of folate. There is evidence that periconceptional folic acid supplements can decrease the risk of neural tube defects in the fetus. For this reason, the United States Public Health Service recommends the consumption of 0.4 mg of folic acid per day for all pregnant and reproductive age women. Women with a prior pregnancy complicated by neural tube defect may require higher supplemental doses as determined by their providers. Lactovegetarians and ovolactovegetarians do well in pregnancy; vegetarian women who eat neither eggs nor milk products should have their diets assessed for adequate calories and protein and should take oral vitamin B12 and vitamin D supplements during pregnancy and lactation.

Salt restriction is not necessary. While consumption of highly salted snack foods and prepared foods is not desirable, 2–3 g/day of sodium is permissible. The increased calcium needs of pregnancy (1200 mg/day) can be met with milk, milk products, green vegetables, soybean products, corn tortillas, and calcium carbonate supplements

Key points: Nutrition during pregnancy...
  • Institute of Medicine (IOM) Recommendations for gestational weight gain for women are set by weight category: underweight (BMI <18.5), normal weight (BMI 18.5 to 24.9), overweight (BMI 25 to 29.9), and obese (BMI >30).
  • During the second trimester, a pregnant woman should consume an additional 340 kcal/day above the nonpregnant energy requirement, and in the third trimester, the additional caloric requirement is 452 kcal/day.
  • Protein requirements during pregnancy increase from 0.8 g/kg/day for nonpregnant women to 1.1 g/kg/day during pregnancy.
  • The daily recommended intake for folate in women of childbearing age is 400 µg/day.
    • Women whose fetuses are at high risk of an NTD should be prescribed a higher dose of folate (4 mg/day) both before conception and in early pregnancy.
  • Iron supplementation is often prescribed during pregnancy because of the (20% to 30%) expanded maternal red cell mass as well as for fetal and placental tissue production.
    • Iron supplements can cause GI side effects such as constipation.
  • Vitamin D supplementation is often required during pregnancy in women with specific dietary preferences or for those with minimal exposure to sunlight.
    • To evaluate vitamin D concentrations before and during pregnancy, check serum 25(OH)D levels and aim for concentrations of 25(OH)D of greater than 20 nmol/L.
    • The Dietary Reference Intakes (DRI) for vitamin D is 600 IU/day in all pregnant and reproductive-age women.
  • Calcium in nonpregnant and pregnant women 19 to 50 years of age is 1000 mg/day, and it is 1300 mg/day for females 9 to 19 years of age.
  • Many common GI problems during pregnancy—such as heartburn, nausea and vomiting, and constipation—are improved with proper nutritional counseling.

References

  1. American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 548: weight gain during pregnancy. Obstet Gynecol. 2013 Jan;121(1):210-2.
  2. Trumbo P, Schlicker S, Yates AA, Poos M; Food and Nutrition Board of the Institute of Medicine, The National Academies. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids. J Am Diet Assoc. 2002;102(11):1621-1630.
  3. Healthy Weight during Pregnancy. [online] Available at: https://www.eatright.org/health/pregnancy/prenatal-wellness/healthy-weight-during-pregnancy.