title: Habitual micronutrient intake during and after pregnancy in Caucasian Londoners. Improved iodine status is associated with improved mental performance of schoolchildren in Benin. Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. The impact of iodine supplementation and bread fortification on urinary iodine concentrations in a mildly iodine deficient population of pregnant women in South Australia Iodine supplementation improves cognition in mildly iodine-deficient children. Iodine supplementation in pregnancy and its effect on child cognition. Postpartum thyroid dysfunction in pregnant thyroid peroxidase antibody-positive women living in an area with mild to moderate iodine deficiency: is iodine supplementation safe? A randomized trial for the treatment of mild iodine deficiency during pregnancy: maternal and neonatal effects. Infant neurocognitive development is independent of the use of iodised salt or iodine supplements given during pregnancy. Iodine prophylaxis using iodized salt and risk of maternal thyroid failure in conditions of mild iodine deficiency. Comparison of two different doses of iodide in the prevention of gestational goiter in marginal iodine deficiency: a longitudinal study. Increased pregnancy loss rate in thyroid antibody negative women with TSH levels between 2.5 and 5.0 in the first trimester of pregnancy. Earliest prevention of endemic goiter by iodine supplementation during pregnancy. Mandatory fortification of bread with iodised salt modestly improves iodine status in schoolchildren. Evolution of thyroid autoimmunity during iodine prophylaxis--the Sri Lankan experience. The effects of iodoprophylaxis on thyroid size during pregnancy. Amelioration of some pregnancy-associated variations in thyroid function by iodine supplementation. Prevalence of thyroid disorders in pregnant women with mild iodine deficiency
abstract: Micronutrient status is of fundamental importance both upon conception and throughout pregnancy . There is an abundance of literature investigating nutrient intakes during individual trimesters of pregnancy but few studies have investigated baseline intakes of nutrients throughout gestation as a continuum . The current investigation set out to measure habitual micronutrient intakes at weeks 13 , 25 , 35 of pregnancy and 6 weeks postpartum using a prospect i ve background information question naire , 4 - 7-day weighed food diary and postnatal question naire . Seventy-two primiparous , Caucasian Londoners were recruited at the study start with 42 completing the first , second , third trimester and postpartum study stages respectively . Study findings indicated that sodium intakes were significantly higher than UK guidelines throughout and after pregnancy ( P < 0.001 ) . Intakes of folate , iron , vitamin D , potassium , iodine and selenium were lower than UK recommendations during and after pregnancy , but to varying levels of statistical significance ( P < 0.05 ) . Only 23 - 38 % of women met UK recommendations for  folate  ( 300 microg day(-1 ) ) through dietary sources . Similarly , only a small percentage of women met dietary guidelines for iron ( 19 - 28 % ) . The findings from the current study indicate that public health interventions may be required to help expectant mothers achieve an optimal diet , particularly after birth when dietary recommendations increase for some micronutrients BACKGROUND An adequate iodine supply in utero and shortly after birth is known to be crucial to an individual 's physical and mental development . The question of whether iodine supplementation later in life can exert a favorable influence on the mental performance of iodine-deficient population s was addressed in various studies , but with contradictory results . OBJECTIVE The aim of this study was to examine the effect of an improvement in iodine status on mental and psychomotor performance of schoolchildren ( 7 - 11 y ) who were moderately to severely iodine deficient . DESIGN The study , which was originally planned as a double-blind , r and omized , placebo-controlled intervention , was carried out in an iodine-deficient population of schoolchildren ( n = 196 ) in northern Benin . As the population began to have access to iodized salt during the 1-y intervention period , the study population was split post hoc-on the basis of urinary iodine concentrations-into a group with improved iodine status and a group with unchanged iodine status . Changes in mental and psychomotor performance over the intervention period were compared . RESULTS Children with increased urinary iodine concentrations had a significantly greater increase in performance on the combination of mental tests than did the group with no change in urinary iodine concentrations . CONCLUSIONS An improvement in iodine status , rather than iodine status itself , determined mental performance in this population , which was initially iodine deficient . These findings suggest a " catch-up " effect in terms of mental performance BACKGROUND Iodine is required for the production of thyroid hormones , which are necessary for normal brain development and cognition . Although several r and omized trials examined the effect of iodine supplementation on cognitive performance in schoolchildren , the results were equivocal . OBJECTIVE We aim ed to ascertain whether providing iodized oil to iodine-deficient children would affect their cognitive and motor performance . DESIGN In a double-blind intervention trial , 10 - 12-y-old children ( n = 310 ) in primary schools in rural southeastern Albania were r and omly assigned to receive 400 mg I ( as oral iodized oil ) or placebo . We measured urinary iodine ( UI ) , thyroid-stimulating hormone ( TSH ) , and total thyroxine ( TT4 ) concentrations and thyroid gl and volume ( by ultrasound ) . The children were given a battery of 7 cognitive and motor tests , which included measures of information processing , working memory , visual problem solving , visual search , and fine motor skills .  Thyroid ultrasound and the biochemical and psychological tests were repeated after 24 wk . RESULTS At baseline , the children 's median UI concentration was 43 microg/L ; 87 % were goitrous , and nearly one-third had low concentrations of circulating TT4 . Treatment with iodine markedly improved iodine and thyroid status : at 24 wk , median UI in the treated group was 172 microg/L , mean TT4 was approximately 40 % higher , and the prevalence of hypothyroxinemia was < 1 % . In the placebo group after the intervention , these variables did not differ significantly from baseline . Compared with placebo , iodine treatment significantly improved performance on 4 of 7 tests : rapid target marking , symbol search , rapid object naming , and Raven 's Coloured Progressive Matrices ( P < 0.0001 ) . CONCLUSION Information processing , fine motor skills , and visual problem solving are improved by iodine repletion in moderately iodine-deficient schoolchildren Mild iodine deficiency during pregnancy can have significant effects on fetal development and future cognitive function . The purpose of this study was to characterise the iodine status of South Australian women during pregnancy and relate it to the use of iodine-containing multivitamins . The impact of fortification of bread with iodized salt was also assessed . Women ( n = 196 ) were recruited prospect ively at the beginning of pregnancy and urine collected at 12 , 18 , 30 , 36 weeks gestation and 6 months postpartum . The use of a multivitamin supplement was recorded at each visit . Spot urinary iodine concentrations ( UIC ) were assessed . Median UICs were within the mildly deficient range in women not taking supplements ( < 90 μg/L ) . Among the women taking iodine-containing multivitamins  UICs were within WHO recommendations ( 150–249 μg/L ) for sufficiency and showed an increasing trend through gestation . The fortification of bread with iodized salt  increased the median UIC from 68 μg/L to 84 μg/L ( p = .011 ) which was still in the deficient range . Pregnant women in this region of Australia were unlikely to reach recommended iodine levels without an iodine supplement , even after the m and atory iodine supplementation of bread was instituted in October 2009 BACKGROUND The effects of severe iodine deficiency during critical periods of brain development are well documented . There is little known about the consequences of milder forms of iodine deficiency on neurodevelopment . OBJECTIVE The objective was to determine whether supplementing mildly iodine-deficient children with iodine improves cognition . DESIGN A r and omized , placebo-controlled , double-blind trial was conducted in 184 children aged 10 - 13 y in Dunedin , New Zeal and . Children were r and omly assigned to receive a daily tablet containing either 150 microg I or placebo for 28 wk .  Biochemical , anthropometric , and dietary data were collected from each child at baseline and after 28 wk . Cognitive performance was assessed through 4 subtests from the Wechsler Intelligence Scale for Children . RESULTS At baseline , children were mildly iodine deficient [ median urinary iodine concentration ( UIC ) : 63 microg/L ; thyroglobulin concentration : 16.4 microg/L ] . After 28 wk , iodine status improved in the supplemented group ( UIC : 145 microg/L ; thyroglobulin : 8.5 microg/L ) , whereas the placebo group remained iodine deficient ( UIC : 81 microg/L ; thyroglobulin : 11.6 microg/L ) . Iodine supplementation significantly improved scores for 2 of the 4 cognitive subtests [ picture concepts ( P = 0.023 ) and matrix reasoning ( P = 0.040 ) ] but not for letter-number sequencing ( P = 0.480 ) or symbol search ( P = 0.608 ) . The overall cognitive score of the iodine-supplemented group was 0.19 SDs higher than that of the placebo group ( P = 0.011 ) . CONCLUSIONS Iodine supplementation improved perceptual reasoning in mildly iodine-deficient children and suggests that mild iodine deficiency could prevent children from attaining their full intellectual potential . The trial was registered with the Australia New Zeal and Clinical Trials Register as ACTRN12608000222347 Maternal hypothyroidism and hypothyroxenemia due to iodine deficiency have been shown to affect development of the newborn negatively . Maternal iodine supplementation may therefore improve cognitive performance of the offspring , even in areas of mild-to-moderate iodine deficiency ( ID ) . Several iodine supplementation studies have been performed in mildly ID pregnant women in Europe . These studies have shown that iodine supplementation increases maternal urinary iodine ( UI ) excretion and reduces thyroid volume , as well as prevents increases in infant thyroid volume and thyroglobuline . However , r and omized controlled studies with long-term outcomes are lacking . Therefore , two trials were started in 2008 in areas of low iodine status ; one in Bangalore , India ( n=325 ) , and another in Bangkok , Thail and ( n=514 ) . Pregnant women were recruited < 14 weeks gestational age and r and omized to either receive a daily dose of 200 μg I ( as KI ) or an identical placebo throughout pregnancy . Both trials are ongoing , and women are followed up during pregnancy and at delivery . UI , thyroid hormones , and thyroid size are measured . Birth outcomes are recorded , such as gestational age at delivery , height , weight , and APGAR scores , and cord blood and heel stick blood ( < 72 h ) is collected from the child . Child development is assessed at 6 weeks of age using the Neonatal Behavioral Assessment Scale ( NBAS ) , and at 12 and 24 months of age using the Bayley Scales of Infant Development . The outcomes of these trials will contribute importantly to the evidence base for iodine supplementation of pregnant women living in areas of mild iodine deficiency In moderately iodine-deficient , pregnant , thyroid peroxidase antibody (TPO-Ab)-positive women the role of iodine supplementation in the development of postpartum thyroid dysfunction ( PPTD ) was studied in a placebo-controlled , r and omized , double blind trial . Screening for TPO-Ab was performed in early pregnancy in a population of healthy pregnant Danish women with no previous diagnosed thyroid disease ( prevalence , 117 of 1,284 ; 9.1 % ) . The participants were r and omized , stratified according to TPO-Ab level , to three groups . All participants received a daily vitamin and mineral tablet with 150 microg iodine or no iodine . The + /+ group received iodine during pregnancy and the postpartum period , the + /- group received iodine during pregnancy only , and the -/- group received no iodine supplementation . A total of 66 TPO-Ab positive women were followed , and in the postpartum period sera were collected at 8-week interval for biochemical evaluation of thyroid function and antibody level . Compliance was evaluated by 24-h urinary iodine measurements . PPTD developed in 55 % of the participants . In 67 % of the cases abnormal TSH was accompanied by abnormalities in thyroid hormones , whereas 33 % had abnormal serum TSH only . There was no statistically significant difference in the frequency of PPTD in the three groups : + /+ group , 59 % ( 95 % confidence interval , 36 - 79 % ) ; + /- group , 60 % ( 36 - 81 % ) ; and -/- group , 46 % ( 26 - 67 % ) . There were also no differences in the severity of the PPTD , as evaluated by duration and grade of deviation of TSH and thyroid hormones from normality . The occurrence , severity , and type of PPTD predominantly depended on the TPO-Ab level : TPO-Ab below 200 U/L at screening , 35 % developed PPTD ; TPO-Ab of 200 - 900 U/L , 54 % ; and TPO-Ab above 900 U/L , 75 % developed PPTD . Women with low levels of antibodies predominantly remained euthyroid or had hyperthyroidism only , whereas women with high antibody levels had hyperthyroidism followed by hypothyroidism or hypothyroidism only . We conclude that iodine supplementation ( 150 microg ) during pregnancy and the postpartum period to TPO-Ab-positive women living in an area with mild to moderate iodine deficiency did not induce or worsen PPTD . The study confirmed that screening for TPO-Ab in early pregnancy can predict women at high risk for development of PPTD One hundred and eighty euthyroid pregnant women were selected at the end of the first trimester of gestation on the basis of biochemical criteria of excessive thyroid stimulation , defined as supranormal serum thyroglobulin ( TG > 20 micrograms/L ) associated with a low normal free T4 index ( < 1.23 ) and /or an increased T3/T4 ratio ( > 25 x 10(-3 ) ) . Women were r and omized in a double blind protocol into three groups and treated until term with a placebo , 100 micrograms potassium iodide (KI)/day , or 100 micrograms iodide plus 100 micrograms L-T4/day . Parameters of thyroid function , urinary iodine excretion , and thyroid volume were monitored sequentially . Neonatal thyroid parameters , including thyroid volume by echography , were also assessed in the newborns from mothers of the three groups . In women receiving a placebo , the indices of excessive thyroid stimulation worsened as gestation progressed , with low free T4 levels , markedly increased serum TG and T3/T4 ratio . Serum TSH doubled , on the average , and was supranormal in 20 % of the cases at term . Urinary iodine excretion levels were low , around 30 micrograms/L at term . The thyroid volume increased , on the average , by 30 % , and 16 % of the women developed a goiter , confirming the goitrogenic stimulus associated with pregnancy . Moreover , the newborns of these mothers had significantly larger thyroid volumes at birth as well as elevated serum TG levels . In both groups of women receiving an active treatment , the alterations in thyroid function associated with pregnancy were markedly improved . The increase in serum TSH was almost suppressed , serum TG decreased significantly , and changes in thyroid volume were minimized ( group receiving KI ) or almost suppressed ( group receiving KI combined with L-T4 ) . Moreover , in the newborns of the mothers in the two groups receiving an active treatment , serum TG was significantly lower , and thyroid volume at birth was normal . The effects of therapy were clearly more rapid and more marked in the group receiving a combination of T4 and KI than in the women receiving KI alone . The differences could be partly attributed to the slightly higher amount of iodine received by women in the combined treatment . However , the main benefits of the combined treatment were almost certainly attributable to the hormonal effects of the addition of L-T4 . Furthermore , the study demonstrated that the administration of T4 did not hamper the beneficial effect of iodine supplementation . In conclusion , the present work emphasizes the potential risk of goitrogenic stimulation in both mother and newborn in the presence of mild iodine deficiency . ( ABSTRACT TRUNCATED AT 400 WORDS The benefits of iodine supplements during pregnancy remain controversial in areas with a mild-to-moderate iodine deficiency . The aim of the present study was to determine the effect of improving iodine intakes , with iodised salt ( IS ) or iodine supplements , in pregnant Spanish women . A total of 131 pregnant women in their first trimester were r and omly assigned to three groups : ( 1 ) IS in cooking and at the table , ( 2 ) 200 μg potassium iodide (KI)/d or ( 3 ) 300 μg KI/d . No differences were found in thyroid-stimulating hormone ( TSH ) , free thyroxine ( FT4 ) , free triiodothyronine ( FT3 ) or thyroid volume ( TV ) between the three groups . Regardless of the group in which women were included , those who had been taking IS for at least 1 year before becoming pregnant had a significantly lower TV in the third trimester ( P= 0.01 ) and a significantly higher urinary iodine in the first ( 173.7 ( sd 81.8 ) v. 113.8 ( sd 79.6 ) μg/l , P= 0.001 ) and third trimesters ( 206.3 ( sd 91.2 ) v. 160.4 ( sd 87.7 ) μg/l , P= 0.03 ) . Also , no differences were seen in TSH , FT4 or FT3 . Children 's neurological development was not significantly associated with the consumption of IS for at least 1 year before becoming pregnant and no differences were found according to the treatment group . In conclusion , in pregnant women with insufficient iodine intake , the intake of IS before becoming pregnant was associated with a better maternal thyroid function . The form of iodide intake was not associated with maternal thyroid function or children 's neurological development CONTEXT Mild to moderate iodine deficiency during pregnancy can cause transient maternal hypothyroidism and impaired mental development of the progeny . These unfavorable effects are preventable by iodine supplementation . In Europe , however , less than 50 % pregnant women receive iodine-containing supplements , thus representing dietary iodized salt the only carrier of iodine for most women in this life stage . OBJECTIVE / DESIGN This longitudinal study is aim ed to investigate the effects of long-term iodized salt consumption on maternal thyroid function during gestation . PARTICIPANTS / OUTCOME MEASURES : We prospect ively evaluated thyroid function in 100 consecutive thyroperoxidase antibody-negative pregnant women from a mildly iodine-deficient area . Sixty-two women who had regularly used iodized salt for at least 2 yr prior to becoming pregnant and 38 who commenced iodized salt consumption upon becoming pregnant were classified as long-term ( LT ) and short-term ( ST ) iodine supplemented , respectively . RESULTS Long-term iodized salt consumption result ed in a very low prevalence of maternal thyroid failure ( MTF ) in LT women . Conversely , short-term iodine prophylaxis does not seem to protect against the risk of MTF , the prevalence of which was almost 6-fold higher in ST than LT women ( 36.8 % vs. 6.4 % ; chi(2 ) 14.7 , P < 0.0005 ; relative risk 5.7 , 95 % confidence interval 2.03 - 16.08 , P < 0.001 ) . The relative risk reduction amounted to 82.5 % , this measure indicating the extent to which long-term iodine prophylaxis using iodized salt would reduce the risk of MTF in ST women . CONCLUSIONS Prolonged iodized salt significantly improves maternal thyroid economy and reduces the risk of maternal thyroid insufficiency during gestation , probably because of a nearly restoring intrathyroidal iodine stores OBJECTIVE A prospect i ve r and omized trial was performed to assess the usefulness of iodine supplementation in the prevention of goiter in pregnant women living in marginally iodine-deficient areas . DESIGN Eighty-six pregnant women were recruited and r and omized in two groups and treated daily for up to six months after delivery with 200 microg iodide ( group A ) or 50 microg iodide ( group B ) . Sixty-seven women ( 32 in group A and 35 in group B ) completed the study . METHODS Thyroid volume ( TV ) , thyroid functional parameters and urinary iodine concentration were determined in all subjects at booking , at the 18th-26th , and the 29th-33rd week of gestation , and at the 3rd and 6th month after delivery . RESULTS A slight but not significant increase in TV during gestation was observed only in group B. After delivery a progressive decrease in TV was documented in both groups , the final TV being significantly reduced with respect to the initial volume in group A. No significant changes in serum free thyroid hormones and TSH concentrations were found during gestation in either group . Postpartum thyroiditis was observed in 5 women ( 2 in group A , 3 in group B ) . No side effects were seen . CONCLUSION The present data indicate that in marginally iodine-deficient areas , the administration of iodide is recommended in pregnancy and lactation . In the conditions of the present trial a dose of 50 microg iodide/day is a safe and effective measure in preventing an increase in TV during pregnancy but a dose of 200 microg iodide/day appeared to be more effective without inducing side effects and without enhancing the frequency of post-partum thyroiditis CONTEXT The definition of what constitutes a normal TSH during pregnancy is in flux . Recent studies suggested that the first trimester upper limit of normal for TSH should be 2.5 mIU/liter . OBJECTIVE The objective of the study was to evaluate the pregnancy loss and preterm delivery rate in first-trimester thyroid peroxidase antibody-negative women with TSH values between 2.5 and 5.0 mIU/liter . DESIGN The present study is a component of a recently published large-scale prospect i ve trial that evaluated the impact of levothyroxine treatment on maternal and neonatal complications in thyroid peroxidase-positive women with TSH levels above 2.5 mIU/liter . The present study evaluated 4123 thyroid peroxidase antibody-negative women with TSH levels at or below 5.0 mIU/liter . Women were divided into two groups based on their initial TSH : group A , TSH level below 2.5 mIU/liter , excluding hyperthyroid women defined as an undetectable TSH with an elevated free T(4 ) , and group B , TSH level between 2.5 and 5.0 mIU/liter . SETTING The study was conducted at two ambulatory clinics of community hospitals in southern Italy . PATIENTS A total of 4123 women were evaluated . INTERVENTION There was no intervention . MAIN OUTCOME MEASURES The incidence of pregnancy loss and preterm delivery in group A as compared with group B was measured . RESULTS The rate of pregnancy loss was significantly higher in group B as compared with group A ( 6.1 vs. 3.6 % respectively , P = 0.006 ) . There was no difference in the rate of preterm delivery between the two groups . CONCLUSIONS The increased incidence of pregnancy loss in pregnant women with TSH levels between 2.5 and 5.0 mIU/liter provides strong physiological evidence to support redefining the TSH upper limit of normal in the first trimester to 2.5 mIU/liter During pregnancy complex changes of maternal thyroid function occur and they are influenced by the maternal iodine supply . It has been demonstrated that with decreasing iodine supply maternal goiter and hypothyroxinemia as well as fetal and neonatal hypothyroidism become more prevalent . Therefore iodine supplementation during pregnancy is now strongly recommended also in areas of moderate iodine deficiency . To monitor the success of iodine supplementation and its theoretical risk of increasing the frequency of thyroid autoantibodies , we have investigated the thyroid volume , thyroid function , urinary iodine excretion and antibodies to thyroid peroxidase at 10 - 12 weeks of gestation and postpartum in 38 mothers receiving 300 micrograms potassium iodide/day and in 70 mothers without iodine supplementation .  In all of their newborns thyroid volume was determined by ultrasound . The thyrotropin ( TSH ) levels and antibodies to thyroid peroxidase ( TPO-ab ) in the neonates were measured in dried blood spots on filter paper from their newborn screening . Urinary iodine excretion was increased significantly after iodine supplementation in mothers ( p < 0.001 ) and their newborns ( < 0.05 ) . No hypo- or hyperthyroidism was observed in the mothers or newborns . Interestingly , no difference of maternal thyroid volumes was observed between the two groups after pregnancy , but the volumes of the thyroid gl and s in newborns of mothers who received iodine were significantly ( p < 0.004 ) lower ( 0.7 + /- 0.4 ml ) than in the control group ( 1.5 + /- 1.1 ml ) . There was no change in the frequency of TPO-ab in either group after pregnancy . In four mothers transplacental passage of these antibodies was documented by positive measurement in the blood sample of the newborn . This study documents that iodine supplementation during pregnancy in an area of moderate iodine deficiency results in a lower size of neonatal thyroid volume and that this supplementation was not accompanied by an increase in the frequency of TPO-ab Iodine deficiency has re-emerged in many parts of the world including the UK , Australia and New Zeal and ( NZ ) . In 2009 , the NZ government introduced the m and atory fortification of bread with iodised salt as a strategy to improve iodine intakes . The aim of the present study was to assess the impact of fortification on the iodine status of NZ schoolchildren . A school-based cluster survey was used to r and omly select schools from two NZ cities . Children aged 8 - 10 years were administered a general question naire , and asked to provide a casual urine and finger-prick blood sample . The median urinary iodine concentration ( UIC ) of the children ( n 147 ) was 113 μg/l , which falls between 100 and 199 μg/l indicating adequate iodine status ; 12 % of children had a UIC < 50 μg/l and 39 % had a UIC < 100 μg/l . The median serum thyroxine concentration was 115 nmol/l . The median serum thyroglobulin ( Tg ) concentration was 10.8 μg/l and falls in the 10.0 - 19.9 μg/l range indicative of mild iodine deficiency , suggesting that these children still had enlarged thyroid gl and s. When compared with the median UIC of 68 μg/l reported in the 2002 NZ Children 's Nutrition Survey , the UIC of children in the present study had increased , which is probably caused by the addition of iodised salt to bread . However , the elevated concentration of Tg in these children suggests that the increase in UIC is not sufficient to ensure that thyroid volume has normalised . The fortification of other staple foods , in addition to bread , should be considered to ensure good iodine status in NZ children OBJECTIVE To study the evolution of thyroid autoimmunity , in relation to the change in goitre prevalence , during 3 Years of iodine prophylaxis  in Sri Lanka . METHODS Two groups of Sri Lankan schoolgirls between the ages of 10.8 and 17.5 Years were studied in 1998 ( 401 girls ) and 2001 ( 282 girls ) . A prospect i ve study was performed in 42 schoolgirls who were thyroid autoantibody (Ab)-positive ( + ve ) in 1998 .  Anthropometric measures , urinary iodine excretion ( UIE ) , thyroid Volume , free thyroxine , free tri-iodothyronine , TSH , and thyroglobulin ( Tg ) and thyroid peroxidase ( TPO ) Ab were evaluated in all 683 girls . RESULTS Goitre prevalence was significantly lower in 2001 compared with 1998 related to age ( 2.9 % compared with 20.2 % ) and body surface area ( 11.6 % compared with 40.8 % ) , although UIE was unchanged . Prevalence of thyroid Ab in 2001 was also lower ( 23.4 % compared with 49.9 % ) ; among those with the Ab , 34.8 % had TgAb alone and 46.9 % had a combination of TgAb+TPOAb , compared with 82.0 % TgAb alone in 1998 . In 2001 , sub clinical hypothyroidism was more frequent in Ab+ve ( 6.3 % ) than Ab-negative girls ( 1.0 % ) . A cohort of 42 Ab+ve schoolgirls in 1998 ( 34 with TgAb alone , eight with TgAb+TPOAb ) were evaluated again in 2001 . Only 10 of them ( 23.8 % ) remained Ab+ve ( mostly TPOAb+/-TgAb ) in 2001 . CONCLUSIONS This study demonstrates that : ( 1 ) in 2001 , goitre prevalence and thyroid autoimmunity rates were significantly lower than in 1998 ; ( 2 ) the pattern of thyroid Ab was different in the two surveys ; ( 3 ) in 2001 alone , the occurrence of hypothyroidism was correlated with the presence of thyroid autoimmunity . These results indicate an evolution of thyroid autoimmune markers during the course of iodine prophylaxis , which has not been described before Thyroid gl and size was ultrasonographically determined in 35 pregnant women who live in an area with moderate iodine deficiency .  Iodide salt was administered to group A ( n = 17 ) , whereas group B ( n = 18 ) was used as a control . Each group was tested for thyroid-stimulating hormone serum levels , iodine excretion , and thyroid volume . In both groups thyroid-stimulating hormone levels were similar and did not change throughout pregnancy . The iodine excretion at the third trimester in the treated group was significantly ( p less than 0.01 ) higher than that of group B ( 100.0 + /- 39.0 versus 50.0 + /- 37.0 micrograms iodine per 24 hours , respectively ) . Initially , thyroid volume did not differ between the two groups . At the end of pregnancy , no difference was found in thyroid size in group A , whereas in the untreated women it increased significantly ( p less than 0.0001 ) with a mean increase of 1.6 + /- 0.6 ml ( 16.2 % + /- 6.0 % ) . These results show that the increased thyroid size in the control group was mainly a result of relative iodine deficiency and that iodoprophylaxis should be warranted even in areas with moderate iodine deficiency to prevent the increase in thyroid size and , probably , to avoid the risk of maternal and fetal hypothyroidism Knowledge of the effect of differences in iodine intake levels on public health in areas with no endemic goiter is limited . Groups at risk when iodine intake is relatively low are pregnant and lactating women and their newborns . A prospect i ve r and omized study was performed to evaluate the effect of iodine supplementation in an area where the median daily iodine excretion in urine is around 50 micrograms . Fifty-four normal pregnant women were r and omized to be controls or to receive 200 micrograms iodine/day from weeks 17 - 18 of pregnancy until 12 months after delivery . In the control group , serum TSH , serum thyroglobulin ( Tg ) , and thyroid size showed significant increases during pregnancy . These variations were ameliorated by iodine supplementation . Iodine did not induce significant variations in serum T4 , T3 , or free T4 . Cord blood Tg was much lower when the mother had received iodine , whereas TSH , T4 , T3 , and free T4 levels were unaltered . The results suggest that a relatively low iodine intake during pregnancy leads to thyroidal stress , with increases in Tg release and thyroid size . However , the thyroid gl and is able to adapt and keep thyroid hormones in the mother and the child normal , at least under normal circumstances , as evaluated in the present study . It is not known whether this stress is sufficient to be of importance for late development of autonomous thyroid growth and function 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
target: 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: 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 .