NUTRITIONAL DEFICIENCIES
While there is widespread public awareness, at least on a basic level, of the importance of good nutrition during pregnancy, what that constitutes is not necessarily clearly understood. Even less well recognized is the importance of a woman’s nutritional status at the time of conception, at preimplantation, and during the early weeks of placental development, before pregnancy is known or confirmed. During this crucial time—three to seven weeks after the last menstrual period—an inadequate diet may result in low–birth-weight infants with lifelong health problems.25 These may include respiratory problems associated with barotrauma from ventilation at birth; neural tube defects; and orofacial clefts.25
Because of inadequate intake of fresh fruits and vegetables, many reproductive-age women in the US are deficient in vitamins A, C, B6, and E, as well as calcium, iron, zinc, magnesium, and folic acid. Although vitamin and mineral supplements are readily available, little clinical research—with the exception of folic acid—has been done on the efficacy of such supplementation.26
Until more is known, intake of these dietary components is best achieved as part of a well-balanced diet; however, this recommendation may need to be modified for African-American women. In a recent retrospective study of almost 2,500 white and African-American women who took a multivitamin supplement consistently during the month before conception, supplementation was associated with increased infant birth weight in the infants born to African-American women but not in those born to white women.26
Folic acid
In the specific case of folic acid, the crucial importance of preconception intake by reproductive-age women is hard to overstate. A well-established body of research supports supplementation to reduce the incidence of neural tube defects that may occur very early in development, before many women are aware of a pregnancy.25-27 However, it is estimated that only a minority of reproductive-age women take a regular folic acid supplement. This may be particularly true of women who are actively avoiding pregnancy and using regular contraception. Patients need to be educated that, as effective as current contraceptive methods are known to be, each method has a typical user failure rate, meaning that actual effectiveness is lower than theoretical effectiveness.
Considering that half of US pregnancies are unintended, with some occurring as a result of contraceptive method or user failures, the FDA Advisory Committee unanimously endorsed the concept of using OCs as a vehicle for folate supplementation.27 There are currently two FDA-approved OCs fortified with the equivalent of 0.4 mg of folic acid. Both contain drospirenone and therefore present a somewhat elevated risk for blood clots, especially in the first year of use.28,29 While this risk is small compared to the incidence of blood clots during pregnancy, a careful history should be taken to avoid prescribing these products to patients already at increased risk for blood clots (eg, obese women, smokers [even light smokers], those with a history of a blood clot after surgery or a motor vehicle accident). For women without risk factors, folic acid–supplemented OCs may be very beneficial should they become pregnant unintentionally or quickly after stopping contraception.
On the next page: Cultural considerations and conclusion >>