Julie Redfern, R.D, L.D.N.
Brigham and Women's Hospital

Congratulations! Your doctor has just confirmed that you are pregnant! You're happy, nervous, excited and feeling responsible for your baby's future. Instead of being worried about eating perfectly, read on for a helpful overview of the most important nutrients you need in pregnancy.

Newer fields of research are focusing on the importance of the fetal experience in preventing chronic disease. Through the studies of such researchers as David Barker, M.D. from Southhampton University in England, it's becoming more apparent that the fetus' environment can have long-term effects on the quality of its adult life, in terms of preventing adult health problems. What you eat, your hormones, and any environmental stresses during pregnancy can influence the quality of your baby's adult life. If these thoughts actually add to your stress, relax! Being informed is more helpful than being anxious.

Eating when pregnant should be a positive experience. As always, you should aim to eat an optimum diet. The good news is that you have some choices about how to eat healthfully for your baby.

Here are some important things to consider.

How much weight should I gain?
There is a healthy range of total weight gain during pregnancy based on your height and pre-pregnancy weight.

Pre-pregnancy Weight
Suggested Weight Gain

Normal weight
25 - 35 pounds

Underweight
28 - 40 pounds

Overweight (greater than 20% of ideal body weight)
15 - 25 pounds

Your rate of weight gain also can influence the long-term health of your baby. An adequate rate is four to six pounds during the first trimester, and about one pound each week during the second and third trimesters. To achieve this weight gain, eat an additional 300 calories a day. You can easily obtain these extra calories by adding a couple of healthy snacks during the day. For example, 4 ounces of yogurt, one slice of whole-grain bread and one tablespoon of peanut or almond butter would be about 300 calories altogether.

While calorie needs increase about 20 percent in pregnancy, some nutrient needs can increase by 50 percent to 100 percent. You need a relatively small increase in quantity of food, but a large increase in quality. We recommend you eat more "nutrient-dense" foods, those packing more nutrients in each calorie.
Foods with excessive calories and very little nutrition, such as tonic, sweets, etc., should be limited.

Target foods containing nutrients needed for an optimal pregnancy, such as protein, calcium, folic acid, iron and Vitamin C.

Consider the Power of Proteins
Proteins are the building blocks of your baby's cells. Complete proteins (sources with all amino acids) are recommended. These include meat, poultry, fish, eggs, milk, cheese, yogurt, and soy. Protein is needed for the baby's growth, as well as for the developing placenta. Protein needs increase by 10 to 15 grams a day. As a reference point, there are 8 grams of protein in: 1 ounce of meat or cheese, 2 tablespoons of peanut butter, 8 ounces milk or yogurt, 1/3 cup of most nuts, and 1/2 cup of beans. Just the addition of two or three high-quality snacks each day, can give you your needed protein.

A word about fish and pregnancy: Fish is an excellent source of not only protein but also omega-3 fatty acids. These are essential fatty acids that cannot be made in our body and must be obtained from our diet. Omega-3 is needed for optimal fetal brain, retinal, and motor development, especially in the third trimester. However, there are some cautions about eating fish in pregnancy. Fish can contain unsafe levels of the natural but toxic element mercury. Mercury is higher in waterways near industrialized cities. High amounts of mercury can cause neurological problems in fetuses and breast-feeding babies. Current recommendations by the Massachusetts Department of Public Health and the U.S. Food and Drug Administration are to limit your intake to 12 ounces per week of safe fish. Safe fish include flounder, shrimp, cod, haddock, mullet, scallops, whitefish, pollack, tilapia,, salmon, sole, mussels, and canned light or chunk light tuna. Avoid swordfish, shark, king mackerel, tilefish and fresh tuna steaks.

Figure In Folic Acid
Folic acid is a B vitamin that's essential for a growing baby. Needs increase in pregnancy, and deficiencies have been associated with problems of the central nervous system such as neural tube defects, especially spina bifida. Since these problems can occur in the first few weeks of pregnancy, it's now advised to increase folic acid when planning pregnancy. Recent research is showing that folic acid is important throughout the pregnancy to help to prevent premature birth. Food sources of this B vitamin include enriched cereals, black and navy beans, black-eyed peas and lentils, asparagus, avocado, orange juice and sunflower seeds. Since your body doesn't store this critical vitamin, it's advised to take a folic acid supplement of 600 micrograms per day. Many prenatal vitamins include 800 microgram to 1 milligram per day. This is a safe amount of folic acid that you can add to your food sources. Women who have previously had a child with neural tube defects may be on therapeutic doses of folic acid. Try to i crease this vitamin by adding beans to salads, soup or pasta dishes. Drink fruit smoothies made with orange juice.

Count On Calcium
Calcium is needed in pregnancy to support the baby's skeletal and teeth development. If not enough is available, your growing baby pulls calcium from your bones. Teeth and bones begin to develop from the second month and double their growth by the sixth month, with large increases by the third trimester. You don't have to be a dairy lover to achieve the recommended needs of 1,200 milligrams per day.
Here are your best bets:

Food Sources
Calcium
(in milligrams)

Yogurt (1 cup)
350 - 400

Milk (1 cup)
300

Cheese ( 1 oz.)
200

Cottage cheese (1 cup)
150

Firm tofu ( 1 cup)
200

Almonds (1/4 cup)
75

Broccoli (1/2 cup)
50

If you have trouble tolerating dairy products due to lactose intolerance or allergies, or you just don't like them, you have a wide choice today from many "designer" milks available. Milk can be lactose free, full fat, low fat, soy, etc. For the most part, the amount of calcium and protein in these products is excellent. However, soy-based milks and yogurts need to be enriched with extra calcium.

Other notable nutrients for pregnancy are iron, vitamin C, vitamin A and zinc. By including many of the foods already mentioned, you will be on your way to increasing these nutrients in your diet as well.

Remember, this should be a positive experience, a time for change with a new future ahead.

Take small steps to improve your present diet and incorporate the added nutrients needed for your future family member. Try not to be worried or stressed about eating well, especially when nausea and fatigue take over. For more information about nutrition and pregnancy consider the following books:

  • Expect the Best: Your Guide to Healthy Eating Before, During, and After Pregnancy. John Wiley & Sons, American Dietetic Association, June 2009.
  • The Harvard Medical School Guide to Healthy Eating During Pregnancy. W. Allan Walker, McGraw-Hill Companies, 2006.
  • Managing Morning Sickness, Miriam Erick, M.S., R.D., Bull Publishing Co., Boulder, CO. 2004.

If you have special nutritional needs, for example if you are carrying multiple or following a vegetarian diet, you may want to seek advice from a registered dietitian who specializes in obstetrical nutrition.

Author's Bio: 

For close to 175 years, Brigham and Women’s Hospital has been the most trusted name in women’s health. Our women health center has been the site for important advances in women’s health. Our team works to improve the health of women and transform their care. For more information about BWH, please visit http://www.brighamandwomens.org/.