In 2016, prenatal care was initiated in the first trimester in more than 75% of pregnancies,¹ providing a multitude of opportunities for family physicians to counsel these patients on the basics of a healthy pregnancy. During prenatal visits, physicians can dispel many myths about pregnancy. This article will discuss physical activity, provide recommendations for weight gain during pregnancy, review components of a well-balanced diet, discuss supplement and medication use, and dispel myths related to topics that have traditionally been taboo: sex and the use of marijuana and alcohol during pregnancy. Communicating this information in an individualized manner will promote maternal and fetal health.

Weight Gain and Diet

The National Academy of Medicine recommends that weight gain during pregnancy be based on preconception body mass index(Table 1).² Patients should be counseled that pregnancy does not require doubling caloric intake.² Weight goals should be individualized according to the baseline fitness level, prepregnancy weight, and other metabolic considerations. A safe recommendation is 350 to 450 calories per day above the previous intake³ (e.g., two slices of bread with half an avocado, ¾ cup of Greek yogurt or 1 cup of blueberries with two hard-boiled eggs). These recommendations optimize birth weight and minimize adverse pregnancy outcomes.^2,4 Excessive weight gain and preexisting maternal obesity are associated with increased antepartum complications, including fetal death, stillbirth, and neonatal death^5,6 (Table 2⁵ ).

When advising pregnant patients about their diet, physicians should counsel about foods to limit or avoid. Foods such as soft cheeses made from unpasteurized milk, deli meats, sprouts, melons not eaten immediately after cutting, and raw or smoked fish can be contaminated with Listeria monocytogenes. The risk of listeriosis is 18 times higher in patients who are pregnant compared with the general population.⁷ Other unpasteurized foods such as kefir, kombucha, and kimchi are less well studied. The Centers for Disease Control and Prevention recommends that all unpasteurized foods be avoided during pregnancy to prevent listeriosis.⁸ The mortality rate of fetal listeriosis is 25% to 35%, depending on the gestational age at the time of infection.⁷

Vitamins and Supplements

A well-balanced diet rich in vitamin D, folic acid, iron, calcium, omega-3 fatty acids, and other micronutrients should be encouraged for pregnant patients (Table 3^3,9–14 ). Prenatal vitamins are recommended because they provide folic acid, iron, calcium, and vitamin D. Ideally, they should be started before conception and should contain at least 400 mcg of folic acid,^2,3 30 mg of elemental iron,^2,3 200 to 300 mg of calcium,⁴ and 400 IU of vitamin D.⁴ Because of the role that vitamin D plays in bone development, the daily recommended intake for patients of childbearing age is 600 IU.⁹ Vitamin D can be obtained from fortified cereals, pasta, breads, cow's milk, cheese, and yogurt.⁹ Salmon and eggs are also excellent sources.⁹ Vitamin D can be synthesized in the skin when exposed to sunlight.⁹

Calcium is an important part of the prenatal diet. The recommended daily intake is 1,000 mg for people 19 years and older and 1,300 mg for those 14 to 18 years of age.⁹ Calcium can be obtained from milk and other dairy sources, and it is present in lower concentrations in dark green leafy vegetables.