What you can do

• Exercise three to five days a week. If you were a couch potato before pregnancy, start with 15 minutes of continuous exercise three times a week, and increase gradually until you hit 30 minutes four days a week. This advice even applies if you’re overweight; obese women with gestational diabetes who exercise in addition to watching their calories gain less weight and deliver leaner babies than those who simply watch their food intake. If you’re a workout veteran, you can stick with your usual routine for as long as it’s comfortable, then cut back as necessary. Regardless of your fitness level, don’t push too hard. If you’re too winded to chat, take it down a notch.

• Stay cool and comfortable when you exercise. Wear breathable clothing, drink enough water, and avoid exercising in a hot, humid environment. Also, don’t exercise while flat on your back after the first trimester, since this can decrease the blood flow to the uterus.

• Eat organic whenever possible. A baby’s developing immune system is much more sensitive than an adult’s, and studies have linked prenatal pesticide exposure to later-in-life immune dysfunctions. Other research suggests that even small doses of pesticides in the water supply may increase the risk of premature births; one study found that preterm birth rates peaked in the months when levels of pesticides in surface water were highest and declined in late summer, when nitrates and pesticides were lowest. The produce harboring the highest pesticide concentrations tend to be fruits and veggies with thin skins, such as peaches, apples, bell peppers and strawberries. The worst offenders are listed here: www.foodnews.org/walletguide.php.

• Don’t “eat for two.” In the first trimester, you may not need any additional calories, and in the second and third trimesters, you need only 300 extra calories per day—that’s equivalent to an apple and 2 tablespoons of peanut butter. Current guidelines recommend that normal weight women gain 25 to 35 pounds during pregnancy (15 to 25 pounds for overweight women), but these standards may soon be revamped downward. Meanwhile, ask your doctor.

• Limit your—and your baby’s—exposure to toxins. Chemical additives used in countless products, from plastics to insect repellants to paints have been linked to shorter pregnancies and, in some cases, birth defects. So to use cleaning products with natural ingredients like baking soda and vinegar, and hold off any home renovation projects, especially sanding, finishing. and installing new carpeting or vinyl flooring. If you paint, choose brands that don’t contain VOCs (volatile organic compounds). To help keep indoor air fresh, open your windows daily, except on high ozone days, and run a wet mop over our floors to control dust particles.

• Choose healthy seafood, avoid mercury. Eat at least 12 ounces a fish a week, or take DHA supplements. DHA is the superstar omega-3 fatty acid that’s key for your baby’s prenatal brain development, leading to better vision, memory, motor skills and language comprehension in early childhood. DHA may also help you avoid postpartum depression. Fish rich in DHA include salmon, trout, herring and sardines. Avoid fish high in mercury, which is a toxic metal that can affect your baby’s developing nervous system. Some types of fish, such as shark, swordfish, king mackerel, and even some kinds of tuna are particularly likely to carry mercury that’s a consequence of industrial pollution. To find out if your favorite finned food is OK to eat, visit the Environmental Defense Fund’s Seafood Selector. Need ideas for preparing fish? Check the Rodale Recipe Finder for suggestions.

And speaking of mercury, recent studies imply that high fructose corn syrup (HFCS), a common sweetener and ingredient in processed foods, may sometimes be contaminated with it. We don’t yet know how widespread or serious this is, but avoiding the many products that contain HFCS is also a good way to cut calories from your diet.

• Add healthy oil. You can also get omega-3’s by cooking with canola oil and using flaxseed oil for salad dressings (flaxseed oil doesn’t hold up to heat). Your body will convert the oil into healthy omegas.

• Take folic acid supplements. In the first trimester, a daily 400-mcg dose reduces neural-tube defects—life-threatening birth defects brain and spine-- by a whopping 50 percent. Adequate folic acid taken prior to pregnancy and in the second trimester also can significantly lower your risk of preterm delivery. Doctors recommend taking folic acid prior to getting pregnant, since brain and spinal-cord defects typically develop in the first weeks of pregnancy, often before a woman knows that she is pregnant. Most prenatal multi-vitamins contain 400 mcg of folic acid, so a separate supplement isn’t necessary. The best food sources: fortified breakfast cereals, dried beans, leafy green vegetables and orange juice.

• Avoid alcohol, limit caffeine. When mom drinks alcohol during pregnancy, baby is more prone to learning disabilities, attention deficit disorder, hyperactivity and aggression. No amount of alcohol is considered safe. As for caffeine, new research shows that even 200 mg of caffeine per day—less than the 300 mg max usually recommended—may increase miscarriage risk. An occasional cup of Joe shouldn’t be a problem, but the less caffeine you drink, the better.

• Junk the junk food. If you spend your pregnancy at Dairy Queen, your child might grow up to be a shake-and-fries-aholic, research on animals suggests. A mother’s sugary, salty, high-fat diet seems to influence her offsprings’ taste preferences. Plus, empty calories like white bread, white rice, sweets and sodas flood your bloodstream, causing your blood-sugar and energy levels to skyrocket and then drop. These blood-sugar spikes are linked to premature birth and smaller babies, and also to lasting damage mom’s arteries. So cut back on the sugary stuff that you know isn’t good for you and replace them with fruits, veggies and hearty whole grains.