Three months before

Watch what you eat
Eating for two should mean being twice as careful about food. Start making choices that boost your metabolism and optimize your hormone levels. Complex carbohydrates (fruits, vegetables, and whole grains) contain fiber that slows digestion and stabilizes your glucose levels. Protein builds a healthy placenta and produces red blood cells; one great source, fish, is also rich in omega-3 fatty acids, which will help your growing baby's brain and nervous system.

Think before you drink
Alcohol raises the risk of physical and mental disabilities, so cut out drinking once you're actively trying to conceive. Heavy drinking--2 or more drinks a day--may increase your estrogen levels, which can cause irregular menstrual cycles and deplete your body of folic acid (the vitamin that protects the fetus from neural-tube defects).

Cut back on caffeine
A study published in The American Journal of Epidemiology found that women who consumed 300 milligrams or more of caffeine a day (equal to three 8-ounce cups of coffee) had twice as much trouble conceiving as those who didn't have any. Yet, most experts say a cup a day is safe.

Consider going organic
Certain environmental toxins may stay in your system and endanger your developing baby. To avoid pesticides, buy organic produce or make sure to wash fruits and vegetables with mild soap. Inhaling certain solvents, paints, and household cleaners has also been shown to cause birth defects and increase miscarriage risk, so make sure your home and workplace are well ventilated.