K Mahomed1, A M Gülmezoglu. 1. Department of Obstetrics and Gynaecology, University of Zimbabwe, PO Box A178, Avondale, Harare, Zimbabwe. kmahomed@healthnet.zw
Abstract
BACKGROUND: Iodine deficiency is the leading preventable cause of intellectual impairment in the world. Although iodine supplementation is generally considered to be safe, there is a possibility of high doses of iodine suppressing maternal thyroid function. OBJECTIVES: The objective of this review was to assess the effects of iodine supplementation before or during pregnancy in areas of iodine deficiency. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register. SELECTION CRITERIA: All acceptably controlled trials of maternal iodine supplementation during pregnancy with clinical outcomes. DATA COLLECTION AND ANALYSIS: Eligibility and trial quality were assessed by two reviewers. MAIN RESULTS: Three trials involving 1551 women were included. In two trials, iodine supplementation was associated with a statistically significant reduction in deaths during infancy and early childhood (relative risk 0.71, 95% confidence interval 0. 56 to 0.90). Iodine supplementation was associated with decreased prevalence of endemic cretinism at the age of four years (relative risk 0.27, 95% confidence interval 0.12 to 0.60) and better psychomotor development scores between four to 25 months of age. REVIEWER'S CONCLUSIONS: Iodine supplementation in a population with high levels of endemic cretinism results in an important reduction in the incidence of the condition with no apparent adverse effects.
BACKGROUND:Iodine deficiency is the leading preventable cause of intellectual impairment in the world. Although iodine supplementation is generally considered to be safe, there is a possibility of high doses of iodine suppressing maternal thyroid function. OBJECTIVES: The objective of this review was to assess the effects of iodine supplementation before or during pregnancy in areas of iodine deficiency. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register. SELECTION CRITERIA: All acceptably controlled trials of maternal iodine supplementation during pregnancy with clinical outcomes. DATA COLLECTION AND ANALYSIS: Eligibility and trial quality were assessed by two reviewers. MAIN RESULTS: Three trials involving 1551 women were included. In two trials, iodine supplementation was associated with a statistically significant reduction in deaths during infancy and early childhood (relative risk 0.71, 95% confidence interval 0. 56 to 0.90). Iodine supplementation was associated with decreased prevalence of endemic cretinism at the age of four years (relative risk 0.27, 95% confidence interval 0.12 to 0.60) and better psychomotor development scores between four to 25 months of age. REVIEWER'S CONCLUSIONS:Iodine supplementation in a population with high levels of endemic cretinism results in an important reduction in the incidence of the condition with no apparent adverse effects.