1. ¹Laboratory for Human Nutrition, Swiss Federal Institute of Technology, Zürich, Switzerland
2. ²International Council for Control of Iodine Deficiency Disorders, Brussels, Belgium

Correspondence: M Zimmermann, Laboratory for Human Nutrition, Institute of Food Science and Nutrition, Swiss Federal Institute of Technology Zürich, Seestrasse 72/Postfach 474, CH- 8803 Rüschlikon, Switzerland. E-mail: michael.zimmermann@ilw.agrl.ethz.ch

Guarantor: M Zimmermann.

Contributors: Both MZ and FD gathered and analyzed the published data and each contributed to the interpretation and discussion. The main preparation of the manuscript was done by MZ with revisions and editing by FD.

Received 9 September 2003; Revised 29 October 2003; Accepted 13 November 2003.

Abstract

Objective: Nearly two-thirds of the population of Western and Central Europe live in countries that are iodine deficient. Damage to reproductive function and to the development of the fetus and newborn is the most important consequence of iodine deficiency. The objective of this review was to examine the iodine status of pregnant women in Europe and the potential need for iodine supplementation.

Design: A MEDLINE/PubMed search and compilation of all published studies since 1990 of iodine nutrition and iodine supplementation of pregnant women in Europe, as well as an Internet-based search and review on availability and legislation of iodine supplements in the European Union.

Results: Although the data suggest most women in Europe are iodine deficient during pregnancy, less than 50% receive supplementation with iodine. Mild-to-moderate iodine deficiency during pregnancy adversely affects thyroid function of the mother and newborn and mental development of the offspring and these adverse effects can be prevented or minimized by supplementation. There are no published data on the effect of iodine supplementation on long-term maternal and child outcomes. The iodine content of prenatal supplements in Europe varies widely; many commonly used products contain no iodine. The European Union is developing legislation to establish permissible levels for iodine in food supplements.

Conclusions: In most European countries, pregnant women and women planning a pregnancy should receive an iodine-containing supplement (150 g/day). Kelp and seaweed-based products, because of unacceptable variability in their iodine content, should be avoided. Prenatal supplement manufacturers should be encouraged to include adequate iodine in their products. Professional organizations should influence evolving EU legislation to ensure optimal doses for iodine in prenatal vitamin–mineral supplements.

Sponsorship: International Council for Control of Iodine Deficiency Disorders.