Effect of Iodine Supplementation and During Pregnancy on Neuropsychological Development of Children Assessed at 2 Years Old

Iodine is required for the synthesis of thyroid hormones. During pregnancy, iodine needs are increased to cover maternal and fetal thyroid hormones synthesis and the increased renal iodine clearance. Maternal hypothyroidism and/or severe iodine deficiency are associated to mental retardation in their offspring. Indeed, thyroid hormones and iodine are necessary for fetal brain development.

Iodine deficiency remains the first cause of preventable mental retardation. In France, preventive programs with salt iodine fortification are insufficient to eradicate iodine deficiency. In previous studies, we have shown that iodine deficiency is the rule for pregnant women in our area: 66 to 85% of women tested depending on the stage of pregnancy (Brucker-Davis 2004, Hieronimus et al 2009, abstract at the 2008 ETA and SFE meetings, article in preparation reporting results from our 2006 PHRC: Study of thyroid function during pregnancy with or without iodine supplementation).We will study the impact of early iodine supplementation in normal pregnant women on the neuropsychological development of their offspring assessed at 2 years of age. This is the follow-up of a cohort of children born to women enrolled in our 2006 PHRC. 110 healthy women have been included in this prospective study: they were seen early (median 8 weeks of gestation) and had strictly normal thyroid function tests, as well as no personal thyroid history. They were randomized into two groups: group A taking pregnancy vitamins without iodine supplementation (Oligobs GrossesseR 2 tablets/day) our group B taking the same vitamins but iodine fortified (Oligobs MaxiodeR 2 tablets per day, i.e. 150 mcg of iodine/day).