Nutrition for the First Trimester of Pregnancy

Aug 16, 2007

Pregnant women, especially those with unique nutrition needs, are encouraged to see a registered dietitian (RD) or other qualified professional for an individualized nutrition plan. However, wellness professionals are often asked questions by their pregnant and nursing clients. You can play a role in helping these clients eat healthily by providing them with the latest research-based news about pregnancy and diet. But you do need to stay within your scope of practice and avoid making recommendations about specific food plans or diets.

A healthy nutrition plan in pregnancy begins with eating small, frequent meals. Those traditional “three square meals a day” are best replaced by five small meals—breakfast, lunch, an afternoon snack, dinner and a bedtime snack. Pregnant women should avoid fasting (>13 hours) and should never skip breakfast, as doing so can increase the risk of a dangerous condition called ketosis, which is an increased acidity of the blood that can increase the risk of preterm delivery. Most nutrition experts caution that it is never healthy to diet during pregnancy (Hacker, Moore & Gambone 2004).

Instead, pregnant women are encouraged to eat an abundance of fruits, vegetables, whole grains and high-calcium foods during the entire gestation period. Other nutrition recommendations are more specific to the exact stage of fetal growth and development, which by convention is divided into pregnancy trimesters and postpartum lactation.

The First Trimester (Weeks 0-12)
Because the body is bombarded with hormonal changes in early pregnancy, at least 70% of moms-to-be experience nausea, vomiting, fatigue, stress and/or other discomforts in the first trimester (ACOG 2004).

For the baby, the first trimester is the most critical period in terms of its future health. The first 3 months mark the time of implantation, organ development and rapid growth. It is when good nutrition is paramount but challenging, especially for women plagued by relentless morning sickness. Weight gain may be nonexistent or up to about 1 pound per month during the first trimester (Hacker, Moore & Gambone 2004).

Obviously, maintaining optimal nutrition through healthful food choices, such as fruits, vegetables, dairy products, whole grains and lean protein, is ideal. But another important task for any future mother is remembering to take a prenatal vitamin every day.

Among a variety of other nutrients, a prenatal vitamin should contain at least 400 micrograms (mcg) of folic acid. Adequate intake of folic acid prevents about 60% of neural-tube defects, such as spina bifida and anencephaly, two devastating neurological abnormalities that result from an improperly formed spinal cord (CDC 2005; MRC Vitamin Study Research Group 1991). Folic acid prevents these kinds of defects if supplementation is initiated in the first several weeks of pregnancy, since the neural tube closes about 3-4 weeks after conception. However, because women often do not know they are pregnant in the first few weeks, public-health officials encourage all women of childbearing age to take a supplement that contains at least 400 mcg of folic acid. And while generous consumption of dark-green, leafy vegetables; fortified cereals; and fruits like oranges and strawberries may provide enough folate, taking a daily prenatal vitamin eliminates the guesswork and assures sufficient intake.

Although folic acid can decrease the risk of severe neurological defects, the Centers for Disease Control and Prevention estimates that only 33% of women of childbearing age take the supplement, and a mere 7% recognize the importance of folic acid prior to becoming pregnant (CDC 2005). It is also vital that vegans (i.e., vegetarians who exclude all animal products) take a vitamin B12 supplement during pregnancy, because a deficiency in this vitamin can also contribute to neural-tube defects.

Iron is another important component of any prenatal vitamin. The CDC recommends that all pregnant women take a daily supplement containing 30 milligrams (mg) of iron, since many women have difficulty maintaining iron stores during pregnancy (CDC 1998). Although research has not established that all pregnant women need an iron supplement, supplementation within recommended doses is not associated with health risks and it helps women maintain iron stores while pregnant. Excellent food sources of iron include lean red meat, fish, poultry, beans, dried fruits and iron-fortified cereals. It should also be noted that vitamin C increases iron absorption, meaning that iron-rich foods (or an iron-fortified supplement) is best taken with orange juice or tomato juice or while dining on other foods that are rich in vitamin C.

Calcium is another important nutrient throughout pregnancy. The developing fetus builds its bones through available calcium in the maternal bloodstream. In the fetus, calcium is also used to conduct nerve impulses and build strong muscles and a strong heart. As with other nutrients, the baby gets access to circulating calcium first. If calcium intake is not adequate, maternal bone strength is at risk. Because calcium absorption increases during pregnancy, the calcium needs of pregnant women are similar to those of nonpregnant women: about 1,000-1,200 mg per day, equivalent to about 3-4 glasses of milk per day (Ritchie & King 2000). Some experts say that adequate calcium intake may also help prevent pregnancy-induced high blood pressure and pre-eclampsia (Ritchie & King 2000). Although calcium is best gleaned through food sources (e.g., dairy products, fortified foods/juices, cooked spinach and broccoli), a calcium supplement can help certain clients meet their nutrition needs during pregnancy. Adequate vitamin D intake is also important for moms-to-be, as it aids in calcium absorption.

Prenatal vitamins provide an abundance of other vitamins and minerals important in early pregnancy. However, vitamins should act more as insurance than as the primary source of nutrition. That’s because, in some cases, it is possible to have too much of a good thing. For instance, consumption of more than 10,000 International Units of vitamin A in early pregnancy can actually cause birth defects (Rothman et al. 1995).

A precaution throughout pregnancy—but especially during the first trimester, when the baby’s organs are developing—is to avoid alcohol consumption. Certainly, many moms-to-be do not know that they are pregnant from the first day of conception and may have had a glass of wine or a couple of beers early in the pregnancy. Most research suggests that this will not cause serious birth defects, since during the first 2 weeks after conception, the fetus will either miscarry or develop normally (Lewanda 2000). However, after 2 weeks, the risks to the fetus increase substantially, depending on the amount of alcohol consumed. Clients should understand that no safe level of alcohol consumption has been established for pregnant women. Alcohol-induced problems, such as mental retardation, learning disabilities and fetal alcohol syndrome and its associated birth defects, are entirely preventable with abstinence. Since it is unknown what amount of alcohol intake can cause fetal damage, health experts advise that alcohol be avoided entirely throughout pregnancy (U.S. Surgeon General 2005; American Academy of Pediatrics 2000).

Caffeine is also a potentially dangerous substance during pregnancy, particularly when consumed in high doses. Caffeine readily crosses the placenta (which develops at the end of the first trimester) and can affect fetal heart rate and breathing. It can also increase the risk of miscarriage, sudden infant death syndrome and low birth weight, according to the American Dietetic Association (ADA 2002), and very high doses may result in congenital anomalies or birth defects (Browne 2006). Although studies have been mostly inconclusive and no one really knows the true risks of caffeine consumption, many experts recommend limiting intake to no more than 300 mg per day—and preferably much less than that (March of Dimes 2007). That’s roughly equivalent to two 8-ounce cups of coffee, three 8-ounce glasses of black tea or five 12-ounce cans of soda per day (March of Dimes 2007). It is especially important to limit caffeine during the first trimester, when the baby’s organs are developing and the risk of miscarriage is highest.

You can help your expectant clients by sharing information on the benefits of eating healthily within the ranges specified in the government’s food pyramid; being physically active at least 30 minutes most days of the week; taking a prenatal vitamin; and breastfeeding if possible. Perhaps most important, remind them that women have been having healthy babies for thousands of years. Finally, suggest that they relax, take a few deep breaths and enjoy this special time in their lives.

American Academy of Pediatrics. 2000. Committee on Substance Abuse and Committee on Children With Disabilities. Policy Statement: Fetal alcohol syndrome and alcohol-related neurodevelopmental disorders. Pediatrics, 106 (2), 358-61.
American College of Obstetricians and Gynecologists (ACOG). 2004. ACOG practice bulletin: Clinical management guidelines for obstetricians-gynecologists. Obstetrics and Gynecology, 103 (4), 803-15.
American Dietetic Association (ADA). 2002. Position of the American Dietetic Association: Nutrition and lifestyle for a healthy pregnancy outcome. Journal of the American Dietetic Association, 102, 1470-90.
Browne, M.L. 2006. Maternal exposure to caffeine and risk of congenital anomalies: A systematic review. Epidemiology, 17 (3), 324-31.
Centers for Disease Control and Prevention (CDC). 1998. Recommendations to prevent and control iron deficiency in the United States. Morbidity and Mortality Weekly Report (MMWR), 47 (3), 1-36.
Centers for Disease Control and Prevention (CDC). 2005. Use of dietary supplements containing folic acid among women of childbearing age--United States, 2005. MMWR, 54 (38), 955-58.
Hacker, N., Moore, J.G., & Gambone, J.C. (Eds). 2004. Essentials of Obstetrics and Gynecology (4th ed.). Philadelphia: Saunders.
Lewanda, A.F. 2000. Fetal alcohol syndrome. Center for Craniofacial Development and Disorders, Johns Hopkins Medical Center.
Source=Physician; retrieved Feb. 4, 2007.
March of Dimes. 2007. Caffeine in pregnancy.; retrieved Mar. 4, 2007.
MRC Vitamin Study Research Group. 1991. Prevention of neural tube defects: Results of the Medical Research Council Vitamin Study. The Lancet, 338, 131-37.
Ritchie, L.D., & King, J.C. 2000. Dietary calcium and pregnancy-induced hypertension: Is there a relation? American Journal of Clinical Nutrition, 71 (5), 1371S-74S.
Rothman, K.J., et al. 1995. Teratogenicity of high vitamin A intake. The New England Journal of Medicine, 333 (21), 1369-73.

U.S. Surgeon General. 2005. News release: U.S. Surgeon General releases advisory on alcohol use in pregnancy.; retrieved Feb. 4, 2007.

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