Iodine Status in Pregnant Women of Puerto Rico

Iodine deficiency is a worldwide public health problem and a preventable cause of neurodevelopmental delay in children. There are no data regarding iodine sufficiency and knowledge on iodine nutrition among pregnant women in Puerto Rico. The objective of this study was to assess iodine status, potential factors influencing iodine status, and knowledge regarding iodine nutrition among Puerto Rican pregnant women.

This was a cross-sectional study of 125 pregnant women recruited from an ambulatory high-risk obstetric clinic in San Juan, Puerto Rico. The participants completed a survey and provided spot urine samples. We excluded women on thyroid medications or those who had undergone iodinated contrast studies in the last 6 months. Spot urine iodine concentrations (UICs) were measured spectrophotometrically.

The median UIC was 182 μg/L. Only 3 (2%) of the participants were aware that pregnant women need increased iodine intake, and 78% reported taking prenatal vitamins, 77% of which were prescription products. The participants who reported taking prescription prenatal vitamins had a median (range) UIC of 148.6 (15.3-1188.6) μg/L compared to those who were not taking prescription prenatal vitamins, who had a median UIC of 249.7 (47.8-2179.0) μg/L (P = .05). The iodine content of the prenatal vitamins was unknown.

The World Health Organization has defined iodine deficiency as a median UIC of <150 μg/L in populations of pregnant women. Our sample of pregnant Puerto Rican women had an adequate iodine status. Most women used prescribed prenatal vitamins with unknown iodine content. The majority of participants reported not receiving any education by health care providers regarding dietary iodine needs.