There were 4,317,119 births in the United States in 2007, the highest number of births ever registered. Although most infants are born healthy, of critical importance is that the infant mortality rate in the United States ranks 29th among developed nations. Preconception care has been advocated as a measure to improve pregnancy outcomes. In 2006, the Centers for Disease Control and Prevention (CDC) published a report aimed at improving preconception care. This report outlined the following 10 recommendations: (1) individual responsibility across the life span, (2) consumer awareness, (3) preventive visits, (4) intervention for identified risks, (5) interconception care, (6) prepregnancy checkup, (7) health insurance coverage for women with low incomes, (8) public health programs and strategies, (9) research, and (10) monitoring improvements. Preconception care can be provided most effectively as part of ongoing primary care. It can be initiated during visits for routine health maintenance, during examinations for school or work, at premarital or family planning visits, after a negative pregnancy test, or during well child care for another family member.

A woman’s nutritional status before pregnancy may have a profound effect on reproductive outcome. Obesity is the most common nutritional disorder in developed countries. Obese women are at increased risk for prenatal complications such as hypertensive disorders of pregnancy, gestational diabetes, and urinary tract infections. They are more likely to deliver large-for-gestational age infants and, as a result, have a higher incidence of intrapartum complications. Maternal obesity is also associated with a range of congenital malformations, including neural tube defects, cardiovascular anomalies, cleft palate, hydrocephalus, and limb reduction anomalies. Because dieting is not recommended during pregnancy, obese women should be encouraged to lose weight prior to conception.

On the other hand, underweight women are more likely than women of normal weight to give birth to low-birth-weight infants. Low birth weight may be associated with an increased risk of developing cardiovascular disease and diabetes in adult life (the “fetal origin hypothesis”).

At the preconception visit, the patient’s weight and height should be assessed and inquiries should be made regarding anorexia, bulimia, pica, vegetarian eating habits, and use of megavitamin supplements.

Vitamin A is a known teratogen at high doses. Supplemental doses exceeding 5000 IU/d should be avoided by women who are, or who may become, pregnant. The form of vitamin A that is teratogenic is retinol, not β-carotene, so large consumption of fruits and vegetables rich in β-carotene is not a concern.

Folic acid supplementation: Neural tube defects (NTDs), including spina bifida, anencephaly, and encephalocele, affect approximately 4000 pregnancies each year in the United States. Although anencephaly is almost always lethal, spina bifida is associated with serious disabilities including paraplegia, bowel and bladder incontinence, hydrocephalus, and intellectual impairment.

Over the past 30 years, multiple studies conducted in various countries have shown a reduced risk of NTDs in infants whose mothers used folic acid supplements. The strongest evidence was provided by the Medical Research Council Vitamin Study in the United Kingdom, which showed a 72% reduction of recurrence of NTDs with a daily dose of 4 mg of folic acid started 4 weeks prior to conception and continued through the first trimester of pregnancy. Additionally, other studies showed a reduction in the incidence of first occurrence NTD with lower doses of folic acid (0.36-0.8 mg). Since 1992, the CDC has recommended that all women of childbearing age who are capable of becoming pregnant take 0.4 mg of folic acid daily to reduce the risk of NTDs in pregnancy. It is also recommended that patients who had a previous pregnancy affected by an NTD take 4 mg of folic acid daily starting 1-3 months prior to planned conception and continuing through the first 3 months of pregnancy.

As of 1998 and in an effort to ensure an increased intake of folic acid, the US Food and Drug Administration (FDA) mandated the fortification of cereals and grains with folic acid at doses of 0.14 mg per 100 g of grain, an amount estimated to increase folic acid consumption by an average of 0.1 mg/d.

A recent report from the CDC showed that from the early postfortification period (1999-2000) to the most recent period of analysis (2003-2005), the prevalence of spina bifida decreased 6.9%. There was significant decrease in prevalence among infants born to non-Hispanic black mothers (19.8%), but not among infants born to non-Hispanic white or to Hispanic mothers. In order to further reduce the prevalence of spina bifida in the United States, public health efforts will need to focus on women with higher risks, such as obesity, Hispanic ethnicity, and certain genetic factors.

More and more women wish to continue with their exercise programs during pregnancy. Among a representative sample of US women, 42% reported exercising during pregnancy. Walking was the leading activity (43% of all activities reported), followed by swimming and aerobics (12% each).

Available data suggest that moderate exercise is safe for pregnant women who have no medical or obstetric complications. A meta-analysis review of the literature on the effects of exercise on pregnancy outcomes found no significant difference between active and sedentary women in terms of maternal weight gain, infant birth weight, length of gestation, length of labor, or Apgar scores.

Exercise may actually reduce pregnancy-related discomforts and improve maternal fitness and sense of self-esteem. The American College of Obstetricians and Gynecologists (ACOG) recommends that exercise in the supine position and any activity that increases the risk of falling (gymnastics, horseback riding, downhill skiing, and vigorous racquet sports) be avoided during pregnancy. Contact sports (such as hockey, soccer, and basketball) should also be avoided as they can result in trauma to both the mother and the fetus. Scuba diving is contraindicated during pregnancy because the fetus is at risk for decompression sickness. Absolute contraindications to exercise during pregnancy are significant heart or lung disease, incompetent cervix, premature labor or ruptured membranes, placenta previa or persistent second- or third-trimester bleeding, and preeclampsia or pregnancy-induced hypertension.

Diabetes

Congenital anomalies occur two to six times more often in the offspring of women with diabetes mellitus and have been associated with poor glycemic control during early pregnancy. Preconceptional care with good diabetic control during early embryogenesis has been shown to reduce the rate of congenital anomalies to essentially that of a control population. In a meta-analysis of 18 published studies, the rate of major anomalies was lower among preconception care recipients (2.1%) than nonrecipients (6.5%).

According to the American Diabetes Association recommendations, the goal for blood glucose management in the preconception period and in the first trimester is to reach the lowest A1c level possible without undue risk of hypoglycemia to the mother. A1c levels that are less than 1% above the normal range are desirable. Suggested pre- and postprandial goals are as follows: before meals, capillary plasma glucose 80-110 mg/dL; 2 hours after meals, capillary plasma glucose less than 155 mg/dL.

Prior to conception, a baseline dilated eye examination is recommended, because diabetic retinopathy can worsen during pregnancy. Hypertension, frequently present in diabetic patients, needs to be controlled. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and diuretics should be avoided as they have been associated with adverse effects on the fetus. Insulin is used almost exclusively in pregnancy for patients with either type 1 or type 2 diabetes. Despite the emerging evidence about the safety of oral hypoglycemic drugs during pregnancy, the ACOG recommends that their use for control of type 2 diabetes during pregnancy should be limited until more data become available.

Hypothyroidism

Approximately 2.5% of pregnant women in the United States have hypothyroidism. Before 12 weeks’ gestation, the fetal thyroid is unable to produce hormones and the fetus is dependent on maternal thyroxine that crosses the placenta. During pregnancy, maternal thyroid hormone requirements increase as early as the fifth week of gestation, typically before the first obstetrical visit. Inadequately treated maternal hypothyroidism is associated with impaired cognitive function in the offspring, as well as pregnancy complications including increased rates of miscarriage, preeclampsia, placental abruption, preterm birth, and low birth weight. Treatment with levothyroxine should be optimized before conception in women with hypothyroidism and they should be advised of the need for increased dosage should they become pregnant.

Epilepsy

Epilepsy occurs in 1% of the population and is the most common serious neurologic problem seen in pregnancy. There are approximately 1 million women of childbearing age with epilepsy in the United States, of whom around 20,000 deliver infants every year. Much can be done to achieve a favorable outcome of pregnancy in women with epilepsy. Ideally, this should start before conception. Menstrual disorders, ovulatory dysfunction, and infertility are relatively common problems in women with epilepsy and should be addressed.

Women with epilepsy must make choices about contraceptive methods. Certain antiepileptic drugs (AEDs), such as phenytoin, carbamazepine, phenobarbital, primidone, and topiramate, induce hepatic cytochrome P450 enzymes, leading to an increase in the metabolism of the estrogen and progestin present in the oral contraceptive pills. This increases the risk of breakthrough pregnancy. The American Academy of Neurology recommends the use of oral contraceptive formulations with at least 50 μg of ethinyl estradiol or mestranol for women with epilepsy who take enzyme-inducing AEDs.

Both levonorgestrel implants (Norplant) and the progestin- only pill have reduced efficacy in women taking enzyme-inducing AEDs. Other AEDs that do not induce liver enzymes (eg, valproic acid, lamotrigine, vigabatrin, gabapentin, and felbamate) do not cause contraceptive failure.

Because many AEDs interfere with the metabolism of folic acid, all women with epilepsy who are planning a pregnancy should receive folic acid supplementation at a dose of 4-5 mg/d. Withdrawal of AEDs can be considered in any woman who has been seizure free for at least 2 years and has a single type of seizure, normal neurologic examination and intelligence quotient, and an electroencephalogram that has normalized with treatment. Because the risk of seizure relapse is greatest in the first 6 months after discontinuing AEDs, withdrawal should be accomplished before conception. If withdrawal is not possible, monotherapy should be attempted to reduce the risk of fetal malformations. Offspring of women with epilepsy are at increased risk for intrauterine growth restriction, congenital malformations that include craniofacial and digital anomalies, and cognitive dysfunction. The term fetal anticonvulsant syndrome encompasses various combinations of these findings and has been associated with use of virtually all AEDs. Some recent studies have indicated a higher risk for birth defects as well as for lower verbal intelligence in association with valproic acid compared with other AEDs, mainly carbamazepine.

Phenylketonuria

Phenylketonuria (PKU) is one of the most common inborn errors of metabolism. It is associated with deficient activity of the liver enzyme phenylalanine hydroxylase, leading to an accumulation of phenylalanine in the blood and other tissues. If untreated, PKU can result in mental retardation, seizures, microcephaly, delayed speech, eczema, and autistic-like behaviors. All states have screening programs for PKU at birth. When diagnosed early in the newborn period and when treated with a phenylalanine-restricted diet, affected infants have normal development and can expect a normal life span.