Pregnancy Nutrition: What Expecting Moms Should Know

Featured Article, Pregnancy, Pregnancy Nutrition


New research shows, more than ever, that what you eat (and how much you eat) from the earliest moments of conception onward can have long-term effects on your baby. PREGNANT-now-what

“We know now that the in utero environment influences genetic expression in the fetus,” says Hope Ricciotti, M.D., author of I’m Pregnant, Now What Do I Eat? and head of obstetrics and gynecology at Beth Israel Deaconess Medical Center in Boston. “Your baby’s future risk for obesity, type 2 diabetes, heart disease and cancer are all influenced by what goes on during pregnancy.”

Gaining too much weight during pregnancy consistently increases the risk of that child being obese, adds Bridget expectantly-eatingSwinney, MS, RD, a registered dietitian and author of Eating Expectantly. But severe calorie restriction early in pregnancy also sets the stage for obesity, she notes. “Overeating seems to reset part of the brain that controls appetite, while undereating activates so-called ‘thrifty’ genes that make your body efficient at storing calories as fat,” she says. “Your goal should be to go into pregnancy at a normal body weight and to gain the amount of weight recommended for your body size.”

While every nutrient—and calorie—is important throughout your pregnancy, here is a breakdown by trimester that highlights new nutrition research findings.

1st Trimester

It might seem outwardly like not much is happening, but at a microscopic level, the baby “blueprint” is being drawn. The nutrients you need now are for proper DNA replication and cell division.


Why: Deficiency of this B vitamin was linked to neural tube defects more than two decades ago. Now folate is known to be intimately tied to genetic expression of the entire genome. It is required to make three out of four of the nucleotides (basic structures) needed to synthesize DNA.

Amount: 600 micrograms a day

Sources: Cooking destroys folate, so you need fresh, raw, uncooked fruits and vegetables. Think spinach salad, other fresh leafy greens, or folate-fortified foods such as orange juice and fortified cereals.


Why: Thyroid function is not yet established in the fetus, so the mother’s thyroid has to do double-duty. Iodine is needed to make thyroid hormones, and need goes up during pregnancy. Low amounts can lead to congenital hypothyroidism and developmental delays. You are more likely to be deficient if you’ve cut back on salt, are using “designer” or kosher salt (generally not iodized) or rely on salty processed foods, which are usually made with un-iodized salt.

Amount: 220 micrograms a day

Sources: Iodized salt, shellfish, seaweed such as powdered kelp.

2nd Trimester

Blood volume starts to increase at the end of the first trimester and is doubled by the end of the second trimester, so this is when blood-building nutrients become important. Fetal growth also takes off, so calorie needs start to increase.


Why: Every red blood cell your body makes needs four molecules of iron to be able to carry its maximum oxygen load. Problems with I.Q. and language development are now linked to iron deficiency in early pregnancy. It’s important to get iron levels back to normal as soon as possible, Dr. Riccoti says.

Amount: 27 milligrams a day, or more if you are deficient

Sources: Lean red meat, poultry, fish, dried beans and peas, and iron-fortified foods, but you’d need to eat food more than your calorie requirements to get enough iron, so supplements are in order, Dr. Riciotti says.

3rd Trimester

During this final growth push, there is a huge amount of brain development. The fetus develops fat stores; its bones and teeth are mineralized.


Why: Brains are nearly 60 percent, and the type of fat matters. You want to cut back on saturated and polyunsaturated fats, and get enough omega-3 fats. DHA, a component of fish oil, kickstarts the growth of new neurons in the brain and is essential for development of the retina and visual cortex.

Amount: The usual recommendation is up to 12 ounces of low-mercury, high-omega-3 fish such as wild salmon, sardines, mackerel or herring a week, Dr. Ricotti says. As for supplements, several studies have evaluated the efficacy of maternal supplementation on infant neurodevelopment or immune response. The studies demonstrating the greatest efficacy have used doses in the range of 1-2 grams a day, much higher than studies reporting negative results and higher than most informal recommendations in the United States.

Sources:  Wild salmon, herring, mackerel, anchovies, certain types of algae.


Why: The majority of the body’s choline is found in specialized fat molecules known as phospholipids, the most common of which is called phosphatidylcholine or lecithin, found in egg yolks. Choline is used to make acetylcholine, an important neurotransmitter. Research now shows that choline in mom’s diet is directly related to fetal brain development, Swinnett says. One recent study found that babies whose moms had low choline in their blood during pregnancy scored lower on cognitive tests at 18 months, indicating that their brain development had been compromised. Rodent studies have also demonstrated that choline during pregnancy increases intelligence into adulthood, and also seems to be protective against memory loss later in life.

Amount: 450 milligrams a day

Sources: Shrimp, egg yolks, shrimp, scallops, chicken, turkey, cod, tun, salmon, and beef. Soy lecithin granules are also a good source.


Why: Deficiency during pregnancy is now known to be associated with poor tooth health for the baby. Vitamin D is needed for tooth enamel to form properly. It’s also needed for proper bone mineralization in the fetus. Deficiency has been linked to infant rickets and easily broken bones that sometimes get mistaken for child abuse.

Amount: 600 IUs a day. Some vitamin D experts recommend 4,000 IUs a day.

Sources: Vitamin D-fortified foods such as milk, supplements, adequate sunlight exposure.


Why: Besides helping mom preserve her own teeth and bones, getting enough calcium and magnesium is now known to help reduce your risk for high blood pressure during late pregnancy. Plus, low magnesium intake during pregnancy is associated with a higher risk for perinatal hypoxia (inadequate oxygen to the brain.)  

Amounts: 1,000 mg a day of calcium; 350-400 mg of magnesium

Sources: dairy products (calcium), almonds, spinach, whole grains, beans (magnesium).

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