How to Have a Happier, Smarter Baby

Pregnant women have tweaked their diets, tried prenatal education tricks, and attempted whatever else baby books and doctors have recommended—all in the quest to have happier, healthier, and perhaps even smarter babies. Mothers-to-be have latched onto fish oil, to cite one example, because of studies crediting omega-3 fatty acids with brighter babies and a lower risk of postpartum depression.

New research suggests none of the above. A study published today in the Journal of the American Medical Associationof more than 2,000 pregnant women who took either fish oil or vegetable oil capsules found no benefit to cognitive or language skills of babies born to fish oil-taking mothers. (Nor did fish oil seem to alleviate their postpartum depression.)

So what can women do to enhance their babies' prenatal experiences and give them a leg-up when they enter the world? In her new book Origins: How the Nine Months Before Birth Shape the Rest of Our Lives, journalist Annie Murphy Paul explores the burgeoning field of fetal origins, which examines how the conditions we encounter before birth influence us down the line. U.S. News spoke with Paul, who shared her insight on which prenatal behaviors withstand scientific scrutiny—and which are shaky at best. Edited excerpts:

Does research support gadgets and other devices marketed to boost babies' intelligence?

Parents often try prenatal education systems, which are completely unsupported by science. There's no indication they will make your baby smarter. Likewise, playing Mozart through headphones to the pregnant belly won't increase intelligence, and could even be harmful. A fetus isn't expecting music to be blasted into the womb, and it may be so loud it causes damage.

What's the deal with chocolate—can eating it during pregnancy really benefit babies, as you say in your book?

Frequent chocolate consumption during pregnancy has been tied to a happier, less fussy baby. Pregnant women who eat five or more servings of chocolate each week have a 40 percent lower risk of developing preeclampsia, a high blood pressure condition [that can endanger the lives of both mother and child]. If you're dying to treat yourself when pregnant, I would suggest some chocolate.

You advocate that pregnant women do a "kitchen purge," especially to discard certain plastics. Why?

Household plastics often contain the chemicals bisphenol A (BPA) and phthalates. These chemicals are endocrine disrupters, which means they imitate the action of chemical messengers in our bodies. Even a small amount can be damaging because our bodies don't recognize them as foreign, and they can mess up the fetus's development process. You can tell if your [plastics contain BPA] by looking at the recycling code on the bottom. Anything labeled 3, 6, or 7 should go in the trash. And don't use plastic in the microwave or put it in the dishwasher, since heat can release BPA.

Speaking of toxins, what's the consensus on alcohol use during pregnancy? A recent study suggests light drinking may not harm the fetus, contrary to traditional advice to abstain.

There's a reason public health experts and doctors always say no amount of alcohol is safe during pregnancy. That's not just an evasion or a stock line—it's true. We don't know how much is safe to drink and how much is problematic. The genetic makeup of the woman and the fetus also plays a role, because both will differ in how they respond to alcohol. That fuzziness is why I decided not to drink at all when I was pregnant. If you're thinking about it, remember that the fetus is most susceptible to damage from alcohol during the first trimester.

Pregnant women often go to great lengths to avoid stress. Should they be so concerned?

Traumatic, life-threatening stress—like being in a war-zone or experiencing a terrorist attack—can have a negative impact on the fetus. Some research shows an association between prenatal stress and cognitive and language skills. The more severe the stressful events, the poorer the infant's abilities, and the greater the rates of attention and behavior problems. That's why we need to have better systems in place for helping pregnant women during emergencies and disasters. Everyday stress, on the other hand, can actually be beneficial. It tones the fetus's nervous system and accelerates brain development.

In Origins, you say that exercising while pregnant makes babies healthier and smarter. Are concerns about overdoing it and harming the fetus unfounded?

Moderate exercise is very beneficial. When a woman works out, her fetus is getting a workout, too. Research suggests that women who exercise while expecting have larger babies who grow up to be smarter adults, perhaps because their brains are bigger. But if you're getting so winded you can't manage to gasp out a sentence, you're probably working out too hard. Pregnant women need to make sure they don't become dehydrated—so, drink a lot of water during and after exercise.

About 20 percent of pregnant women experience mood or anxietydisturbances, and at least 10 percent develop full-blown depression, according to your book. How does this affect the fetus?

Pregnant women who are depressed are more likely to deliver early and have babies with a low birth weight. The mother's emotional state can also influence the fetus's developing brain and nervous system, and potentially shape the way the baby will experience and manage its own emotions. Plus, babies born to depressed mothers are more likely to be irritable and have trouble sleeping. Pregnant women should be screened for depression, just as we screen for gestational diabetes.

Pregnant women are inundated with tips: Do this, but avoid that—until next week, when the advice changes. How can women become more savvy about what's worthwhile, and what they should approach more skeptically?

Women should read and learn as much as they can, and talk with their obstetrician. And remember that the fetus is resilient. We've been giving birth to babies for the entire history of humanity. If you're thinking about it and worrying about it, you're probably doing the best you can.

What's the single most important habit for pregnant women to adopt?

Nutrition. What a woman eats and drinks during pregnancy is so important—not only for her own health, but for the health of her offspring into infancy, childhood, and potentially even adulthood. Eat a well-balanced, healthy diet, with fruits, vegetables, whole grains, and fish. A lot of women are scared to eat seafood because of warnings about mercury, but it actually facilitates fetal brain development. Opt for kinds that are low in mercury: sardines, anchovies, tilapia, salmon, or shell-fish.