The New Pregnancy Nutrition Rules

US News

When I was in graduate school, Bridget Swinney's book on infant feeding, "Baby Bites," was one of my textbooks for a course on pediatric nutrition. Later on in life, I returned to her book for help navigating the thorny waters of transitioning my own kids to solids.

Recently, I heard she had published a fourth edition of "Eating Expectantly," a veritable bible for pregnancy nutrition. So I rushed out to get a copy, devoured it in one sitting and stalked her online to score an interview for this column.

"Eating Expectantly" is misleadingly titled--it's not just a book about pregnancy nutrition, is it?

It's really a lifestyle book about the whole "pregnancy season," encompassing pre-conception, pregnancy and that post-baby time when nutrition is important for breastfeeding and getting back in shape.

[See Trouble Trying to Conceive? This May Be Why.]

While food plays an important role in having a healthy baby, environmental influences like chemicals also contribute to a developing baby's "diet" in utero. This fourth edition focuses on living "cleaner" to keep baby's environment safe.

Yes, I was impressed to see how much discussion you devote to cosmetic and household chemicals that may affect pregnancy outcomes. What should women be on the lookout for?

Endocrine-disrupting chemicals can mimic, increase or decrease the action of hormones in the body. They are suspected as contributing to the worldwide decline in semen quality as well as physical abnormalities of the male reproductive tract. Such chemicals are found in amniotic fluid and semen and arrive there in the most innocuous of ways.

A person can be exposed to dozens of chemicals before she even leaves the house in the morning! People should read labels of makeup and household cleaners as closely as they would food labels. We're concerned about possible lead in lipstick; endocrine disrupting chemicals like phthalates in air fresheners, lotions, nail polish and cleaning products; Bisphenol-A (BPA) in canned foods; and pesticides on conventionally-grown produce.

[See How Safe Are Your Cosmetics?]

The term "fragrance" on a label often means it contains phthalates--a family of chemicals used in the manufacture of some plastics and personal care products. Some phthalates can be found on the label as DEP, DEHP, DBP and BBP, if they're listed at all. Other things to avoid include formaldehyde, propylene glycol (PG), polyethylene glycol (PEG) and paraben preservatives like methylparaben.

Let's switch gears: pre-natal vitamins and supplements. Everyone knows folic acid is the most important nutrient to supplement. But your book addresses other essential nutrients that seem not to appear in the average pre-natal vitamin--or at least not in recommended doses.

Vitamin D is a good example of this. Inadequate vitamin D during pregnancy has been linked to bacterial vaginosis, gestational diabetes, pre-eclampsia and decreased bone mass in offspring. Most prenatal supplements provide the current recommended Vitamin D intake for pregnancy--600 international units (IU). However, research consistently suggests that many women start their pregnancies with insufficient or deficient Vitamin D levels, so that dose is not enough.

Many researchers recommend supplementing at least 1,000 IU, but I think it's safer to have your vitamin D level tested so your doctor can advise a dose based on your specific needs.

Are there other nutrients we should be seeking out from supplements or diet?

Choline is one. It's important for the developing brain. Recently, mothers' low intakes have been linked to neural tube defects in their embryos. The best sources are actually beef or chicken liver, which I don't recommend during pregnancy due to their high vitamin A content (which can contribute to birth defects if taken in excess during the first trimester). Other good sources include eggs, cod, lean beef and Brussels sprouts.

[See Pregnant? Get Your Choline!]

Iodine is another. It's a vital component of thyroid hormone, which controls metabolism and is important for brain development. A deficiency during pregnancy can cause birth defects and impaired cognitive function in baby. Several factors can lead to inadequate iodine intake: People get much of their sodium from sodium-based preservatives or added salt that doesn't necessarily contain iodine; others are wisely cutting back on salt intake; and some have switched to sea salt, which may not contain iodine. Buying iodized salt, and choosing iodine-rich foods like cod, milk, potatoes and an occasional serving of seaweed are good ways to ensure adequate iodine intake.

I deal with pregnant women who are so nauseous that they're pounding ginger ale and lemon sodas like it's their job. Your book, however, emphasizes the importance of avoiding excess sugar intake during pregnancy to help prevent gestational diabetes. Are artificial sweeteners a preferable alternative?

My motto is moderation, and some foods should be eaten with more moderation than others! Of course, during times when nausea keeps you from eating at all, ginger ale and juice do a good job of increasing calorie and fluid intake. But generally, I urge moms to eat "smart carbs"-- healthier, slowly digested carbs like whole grains, fruits and vegetables--and to keep sweet treats and drinks to a minimum.

Substituting artificial sweeteners is not really an advisable alternative. Research from Denmark showed a significant increase in pre-term delivery for pregnant women who had more than one beverage sweetened with aspartame daily. While this study doesn't prove cause and effect, it does warn moms-to-be to think twice about their daily drink choices. To be safe, pregnant women should avoid regular intake of artificial sweeteners--and, at the most, have them only a few times a week.

Alternative "natural" sweeteners have pros and cons, too. Stevia, though used for many years in other countries, hasn't been tested for reproductive effects, according to the Center for Science in the Public Interest. Some sugar alcohols show promise, though. A natural sweetener I'm excited to recommend is Nectresse. It's made from erythritol and monk fruit extract.

[See Prenatal Yoga: What You Should Know.]

So pregnant women need more vitamins, and you're taking away their soda. That's a raw deal. What can you offer them in return?

How about chocolate? I consider natural cocoa and dark chocolate "super condiments" for pregnancy!

A growing body of research links these chocolates to improved blood vessel function, which is important for cardiovascular health. Several studies have linked regular chocolate consumption in the first and/or third trimester to reduced risk of pre-eclampsia. Eating chocolate only in the first trimester seems to decrease the risk of hypertension during pregnancy.

The perfect "dose" for pregnancy hasn't been established, but one to three servings per week of any cocoa-containing foods (hot cocoa, chocolate milk, chocolate chips ... ) appear to decrease the risk of pre-eclampsia. More than three servings doesn't seem to decrease the risk further. I recommend a half ounce of dark chocolate or 1 to 2 tablespoons of cocoa powder daily.

[See Make Room for Chocolate.]

Thanks for sharing these terrific insights--I almost want to get pregnant again just so I can try out some of your sample menus for pregnancy. (Almost.)

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns, and feedback.

Tamara Duker Freuman, MS, RD, CDN, is a NYC-based registered dietitian whose clinical practice specializes in digestive disorders, Celiac Disease, and food intolerances. Her personal blog, www.tamaraduker.com, focuses on healthy eating and gluten-free living.

View Comments