Dr. Ricardo Yazigi

by Dr. Eric Levens

Claims abound that nutritional supplements will improve our health are constantly in the headlines. While nutritional supplements may provide some health benefits including pregnancy-related outcomes, nutritional supplements may not be as safe as they would seem, especially when considering early fetal development.

I frequently get asked about vitamins with respect to fertility. Many patients are surprised to learn that excessive vitamin intake may result in serious medical conditions and have been associated with fetal malformations. This is especially the case for fat-soluble vitamins (A, D, E and K). In general, additional nutritional supplementation outside of a standard prenatal vitamin is not necessary. A typical prenatal vitamin will provide sufficient vitamins and minerals for a healthy early pregnancy. The amount of vitamin A, for example, in standard prenatal vitamins (4,000 to 5,000 IU) is considered the maximum recommended dose before and during pregnancy.1

Another concern with nutritional supplements is that numerous supplements have been found to contain contaminants such as toxic plant materials, heavy metals and even prescription medications, to name a few. These compounds pose serious potential consequences for a developing fetus. Prior to 1994, dietary supplements (vitamins, minerals, amino acids, and botanicals) were considered food additives and thus were required to demonstrate safety prior to product marketing. Since the passage of the Dietary Supplement Health and Education Act, supplements are now presumed to be safe until shown otherwise. Relaxed Federal regulation, largely unknown by consumers and physicians alike, has created an environment in which hazardous supplements may be produced with little product liability. To date, more than 140 contaminated products have been identified, but this likely represents only a small proportion of the total contaminated products available today.2

There has been little conclusive research demonstrating a benefit of nutritional supplements for fertility or early fetal development. A notable exception is folic acid. Folic acid has been shown to reduce the incidence of a specific birth defect known as neural tube defects by as much as 36 percent.1 As a result, the Centers for Disease Control and Prevention and my former agency, the US Public Health Service, recommend that women of reproductive age take 0.4 mg of folic acid daily before conception and during the first trimester. For women with a prior history of a pregnancy affected by a neural tube defect and for women taking anti-seizure medications, 4 mg (10 times the amount) of folic acid in the months in which conception is attempted and for the first trimester is expected to reduce this risk by a remarkable 80 percent.

Nutrition is an essential component of preconception care for all patients. The combination of a well-balanced, varied diet that is consistent with a woman’s food preferences and a standard prenatal vitamin should be sufficient to meet the dietary needs of a developing pregnancy.

Please feel free to write comments on this blog and as always, I wish you the best in your pursuit of a fertile future.

1. American College of Obstetricians and Gynecologists. (2007). Guidelines for perinatal care. Elk Grove Village, IL
2. Cohen, P. A. (2009). “American roulette — contaminated dietary supplements.” N Engl J Med 361(16): 1523-1525.