Controlled trials on infant neurodevelopment were lacking ; gestational iodine supplementation reduced maternal thyroid volume and serum thyroglobulin and in some studies prevented a rise in serum thyroid-stimulating hormone .
Iodine supplementation improves some maternal thyroid indices and may benefit aspects of cognitive function in school-age children , even in marginally iodine-deficient areas .
BACKGROUND Although the detrimental effects of severe iodine deficiency are well recognised , the benefits of correcting mild-to-moderate iodine deficiency are uncertain .
OBJECTIVES We undertook a systematic review of the impact of iodine supplementation in population s with mild-to-moderate iodine deficiency .
Prevalence of thyroid disorders in pregnant women with mild iodine deficiency
To assess the prevalence of thyroid disorders in a region with mild iodine deficiency , this study was undertaken in a r and omized sample of pregnant women during different gestational periods . Evaluations were performed in 215 women : thyroid ultrasound scanning , thyroid stimulating hormone ( TSH ) , free thyroxine ( T4 ) and thyroid peroxidase ( TPO ) antibodies .  At the time of participation in the study , some women ( 90/215 ) had been receiving 150–200 µg iodine .  Hypothyroidism was found in four women ( 1.86 % ) . Positive TPO antibodies were seen in 34 of 215 women ( 15.8 % ) , and TPO antibody level over 150 mU/l was found in 9.8 % ( 21/215 ) . There was no significant difference between TSH levels in women with positive or negative TPO antibodies . There were no differences in TSH level between the women receiving and those not receiving iodine prophylaxis .  The prevalence of goiter in 211 euthyroid women was found to be 24.2 % ( 51/211 ) . In the group with iodine prophylaxis , thyroid volume was found to be significantly lower ( t = 2.5 ; p = 0.02 ) than in women who had not received it , or had started it during the second trimester . By comparison of history data on the prevalence of aborted pregnancy between the group with positive ( 26.5 % ; 9/34 ) and the group with negative TPO antibodies ( 14.3 % ; 26/181 ) , no significant differences were found . We conclude that , in mild iodine deficiency , pregnancy is related to a high risk of goiter , which can be prevented by iodine prophylaxis . TPO antibody carrier status in pregnant women is probably not associated with a significant risk of thyroid dysfunction or spontaneous abortion
Controlled trials on infant neurodevelopment were lacking ; gestational iodine supplementation reduced maternal thyroid volume and serum thyroglobulin and in some studies prevented a rise in serum thyroid-stimulating hormone .
Iodine supplementation improves some maternal thyroid indices and may benefit aspects of cognitive function in school-age children , even in marginally iodine-deficient areas .
BACKGROUND Although the detrimental effects of severe iodine deficiency are well recognised , the benefits of correcting mild-to-moderate iodine deficiency are uncertain .
OBJECTIVES We undertook a systematic review of the impact of iodine supplementation in population s with mild-to-moderate iodine deficiency .