To the Editor.
—As physicians involved in the care of pregnant women, we found the article by Dr Goldenberg and colleagues1 dealing with the purported effect of zinc supplementation on pregnancy outcome interesting. The clear inference made by the authors, that 25 mg of zinc should be included in prenatal multivitamin/mineral tablets for general use, seems unsupported by the data.The study population consisted of 589 medically indigent African-American women with low plasma zinc levels. Even in this very specific group when appropriate adjustments were made for gestational age, "zinc supplementation was associated with an increase in birth weight of 38 g... and an increase in head circumference of 0.21 cm, neither of which was significant" (emphasis added). This is discordant from the claim made in the abstract, in which zinc supplementation was touted as being associated with a significant improvement in both of these factors. Even if zinc
Willette PN, Kiser WR. Zinc Supplementation During Pregnancy. JAMA. 1995;274(24):1909. doi:10.1001/jama.1995.03530240019021