Iodine Status of Pregnant Women and Their Progeny in the Minho Region of Portugal

Background: Iodine sufficiency is particularly necessary throughout pregnancy, given its recognized impact on psychomotor performance of the offspring. There are no recent reports about iodine status or supplementation in Portugal, a country that the International Council for Control of Iodine Deficiency Disorders considered, in 2004, to have probably reached iodine sufficiency. The objective of this study was to evaluate in the Minho region of Portugal the iodine status of women throughout pregnancy and after delivery, and of their offspring. Methods: Urinary iodine concentration (UI) was determined in 78 nonpregnant premenopausal women, in 140 pregnant women in the three trimesters of pregnancy and after delivery, and in their 142 offspring. Milk iodine concentration was determined at day 3 and 3 months after delivery. The thyroid volume was determined in women in the third trimester of pregnancy and 3 months after delivery and in infants at 3 months of age. Results: Based on the World Health Organization criteria, both nonpregnant and pregnant women had iodine deficiency (ID), as documented by median UI of < 75 mu g/L and milk iodine concentration of < 100 mu g/L. Goiter was observed in 14% of the pregnant women. Concordant with the mother's ID, median neonatal UI was low (71 and 97 mu g/L at 3 days and 3 months of age). Conclusion: Portuguese women of the Minho region have an inadequate iodine intake, which may compromise the potential for full psychomotor development of their progeny. These observations suggest that iodine supplementation should be implemented throughout pregnancy and lactation in Portugal.