Development of thyroid gland volume during the first 3 months of life in breast-fed versus iodine-supplemented and iodine-free formula-fed infants Efficacy of daily and weekly multiple micronutrient food-like tablets for the correction of iodine deficiency in Indonesian males aged 6-12 mo. Breast-milk iodine concentration declines over the first 6 mo postpartum in iodine-deficient women. Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. The nutritional iodine supply of Belgian neonates is still insufficient Iodine status and thyroid function of pregnant, lactating women and infants (0-1 yr) residing in areas with an effective Universal Salt Iodization program. Urinary iodine excretion as a predictor of the iodine content of breast milk. Reference values for spot urinary iodine concentrations in iodine-sufficient newborns using a new pad collection method. Iodine supplementation in pregnancy and its effect on child cognition. Iodine Concentration in Breastmilk and Urine among Lactating Women of Bhaktapur, Nepal Iodine supplementation improves cognition in mildly iodine-deficient children. Infant neurocognitive development is independent of the use of iodised salt or iodine supplements given during pregnancy. Effects of iodine supplementation during pregnancy on child growth and development at school age. The impact of iodine supplementation and bread fortification on urinary iodine concentrations in a mildly iodine deficient population of pregnant women in South Australia Treatment of iodine deficiency in school-age children increases insulin-like growth factor (IGF)-I and IGF binding protein-3 concentrations and improves somatic growth. Randomised trial of iodine intake and thyroid status in preterm infants Efficacy and safety of iodine in the postpartum period in an area of mild iodine deficiency.
Summary The spontaneous development of thyroid gl and volume ( TGV ) during the first 3 months of life was studied in entirely breast-fed infants ( n = 21 ) and compared to those fed an iodine-supplemented formula ( n = 19 ) , an iodine-free formula ( n = 5 ) , or partially breast-fed in addition to an iodine-free ( n = 4 ) or an iodine-supplemented formula ( n = 16 ) . The TGV of the infants and their mothers was determined sonographically in addition to their urinary iodine concentrations 57 days postpartum and 3 months later . In ten additional lactating mothers the breast milk concentrations of thyroid hormones and iodine were determined . It was shown that at 3 months of age an infant consuming about 1000 ml breast milk per day receives about 2 μg thyroid hormones and 55 μg iodine per day . At the end of their first week of life the infants showed a TGV between 0.28 and 1.5 ml ( median 0.61 ml ) and a urinary iodine concentration between 0.03 and 16.3 μg/dl ( median 3.0 μg/dl ) . At 3 months of age the TGV of the breast-fed infants had decreased by a median of 0.24 ml (= −34 % ; median of percentage changes ) whereas those fed a formula without iodine had increased by a median of 0.26 ml (= + 50 % ; median of percentage changes ) . Those receiving an iodine-supplemented formula  showed a TGV reduction of 0.14 ml (= + 2 % ; median of percentage changes ) . The TGV development of the partially breast-fed infants lay between those being exclusively breast or formula fed . It is concluded that with respect to the development of TGV , breast milk is superior even to the feeding of an iodine-supplemented formula BACKGROUND Infants are highly vulnerable to iodine deficiency , and little data exist on the effect of multiple micronutrient supplementation on their iodine status . OBJECTIVE We aim ed to compare the efficacy of daily and weekly multiple micronutrient food-like tablets ( foodLETs ) on increasing iodine status among infants . DESIGN In a double-blind , placebo-controlled trial , 133 Indonesian males aged 6 - 12 mo were r and omly assigned to 1 of 4 groups : a daily multiple-micronutrient foodLET providing the Recommended Nutrient Intake (RNI)(DMM ) , a weekly multiple-micronutrient foodLET providing twice the RNI ( WMM ) , a daily 10-mg Fe foodLET ( DI ) , or placebo .  Urinary iodine ( UI ) concentrations were measured at baseline and at 23 wk . RESULTS At baseline , the average UI concentration ( 1.37 micromol/L ) was within the normal range , and 30.8 % of subjects had iodine deficiency ( UI < 0.79 micromol/L ) . At 23 wk , the DMM group had the highest increment in UI ; however , after adjustment for initial UI , the changes in UI were not significantly different between the 4 groups ( P = 0.39 ) . Initial UI correlated inversely with the changes in UI ( P < 0.001 ) . The DMM group had the greatest reduction and increment in the proportion of iodine-deficient infants and in infants with iodine excess , respectively ; however , no significant difference was found in these proportions ( P = 0.13 and P = 0.42 ) between the 4 groups . CONCLUSION Daily consumption of a multiple-micronutrient foodLET providing the RNI during infancy may be one strategy to improve iodine status BACKGROUND Little is known about the iodine status of lactating mothers and their infants during the first 6 mo postpartum or , if deficient , the amount of supplemental iodine required to improve status . OBJECTIVE The objective was to determine maternal and infant iodine status and the breast-milk iodine concentration ( BMI C ) over the first 6 mo of breastfeeding . DESIGN A r and omized , double-blind , placebo-controlled supplementation trial was conducted in lactating women who received placebo ( n = 56 ) , 75 μg I/d ( n = 27 ) , or 150 μg I/d ( n = 26 ) after their infants ' birth until 24 wk postpartum .  Maternal and infant urine sample s and breast-milk sample s were collected at 1 , 2 , 4 , 8 , 12 , 16 , 20 , and 24 wk . Maternal serum thyrotropin and free thyroxine concentrations were measured at 24 wk . RESULTS Over 24 wk , the median urinary iodine concentration ( UIC ) of unsupplemented women and their infants ranged from 20 to 41 μg/L and 34 to 49 μg/L , respectively , which indicated iodine deficiency ( ie , UIC < 100 μg/L ) . Mean maternal UIC was 2.1 - 2.4 times higher in supplemented than in unsupplemented women ( P < 0.001 ) but did not differ significantly between the 2 supplemented groups . BMI C in the placebo group decreased by 40 % over 24 wk ( P < 0.001 ) and was 1.3 times and 1.7 times higher in women supplemented with 75 μg I/d ( P = 0.030 ) and 150 μg I/d ( P < 0.001 ) , respectively , than in unsupplemented women . Thyrotropin and free thyroxine did not differ significantly between groups . CONCLUSION BMI C decreased in the first 6 mo in these iodine-deficient lactating women ; supplementation with 75 or 150 μg I/d increased the BMI C but was insufficient to ensure adequate iodine status in women or their infants . The study was registered with the Australian New Zeal and Clinical Trials Registry as ACTRN12605000345684 BACKGROUND Iodine deficiency in infants can damage the developing brain and increase mortality . Present recommendations state that oral iodised oil should be given to breastfeeding mothers to correct iodine deficiency in infancy when iodised salt is not available , and that direct supplementation should be given to infants who are not being breastfed or receiving iodine-fortified complimentary foods . However , there is little evidence for these recommendations . We aim ed to assess the safety and efficacy of direct versus indirect supplementation of the infant . METHODS We did this double blind , r and omised , placebo-controlled trial in Morocco . Healthy breastfeeding mothers and their term newborn babies ( aged ≤8 weeks ) were block r and omised by clinic day to receive either : one dose of 400 mg iodine to the mother and placebo to the infant ( indirect infant supplementation ) , or one dose of about 100 mg iodine to the infant and placebo to the mother ( direct infant supplementation ) . R and omisation was masked to participants and investigators . Co primary outcomes were : maternal and infant urinary iodine concentrations , breastmilk iodine concentration , maternal and infant thyroid-stimulating hormone ( TSH ) concentrations , maternal and infant thyroxine ( T4 ) concentrations , and infant growth . These outcomes were measured at baseline , and when infants were aged about 3 months , 6 months , and 9 months , and the two groups were compared using mixed effects models . This study is registered with Clinical Trials.gov , number NCT01126125 . FINDINGS We recruited 241 mother-infant pairs between Feb 25 , and Aug 10 , 2010 , and completed data collection by Aug 6 , 2011 . At baseline , median urinary iodine concentration was 35 μg/L ( IQR 29 - 40 ) in mothers and 73 μg/L ( 29 - 237 ) in infants , suggesting iodine deficiency . During the study , maternal urinary iodine concentration ( p=0.011 ) , breastmilk iodine concentration ( p<0.0001 ) , and infant urinary iodine concentration ( p=0.042 ) were higher in the indirect infant supplementation group than in the direct supplementation group . Maternal TSH ( p=0.276 ) and T4 ( p=0.074 ) concentrations did not differ between the groups over the course of the study , nor did infant TSH ( p=0.597 ) and T4 ( p=0.184 ) concentrations , but the number of infants with thyroid hypofunction was lower ( p=0.023 ) in the indirect supplementation group than the direct supplementation group . The infant groups did not differ in anthropomorphic measures , except that length-for-age Z score was slightly greater in the direct infant supplementation group ( p=0.032 ) . At 3 months and 6 months of age , median infant urinary iodine concentration in the indirect infant supplementation group was sufficient ( > 100 μg/L ) , whereas infant urinary iodine concentration was sufficient only at 6 months in the direct supplementation group . There were no serious adverse events in either group . INTERPRETATION In regions of moderate-to-severe iodine deficiency without effective salt iodisation , lactating women who receive one dose of 400 mg iodine as oral iodised oil soon after delivery can provide adequate iodine to their infants through breastmilk for at least 6 months , enabling the infants to achieve euthyroidism . Direct supplementation is less effective in improving infant iodine status . FUNDING ETH Zurich , Switzerl and ; the Medicor Foundation , Vaduz , Lichtenstein Abstract . Belgium used to be affected by mild iodine deficiency . Improvement in iodine nutrition has been recently documented in schoolchildren in Belgium in spite of the absence of any systematic programme of iodine supplementation . The question arises as to whether this ' silent iodine prophylaxis ' affected also the neonates . A total of 185 r and om urine sample s were collected from 90 full term and 65 preterm neonates in Brussels on day 5 and repeated on day 30 in 30 preterms who were bottle-fed with iodine-enriched formula-milk . The iodine content was also determined in 58 sample s of breast-milk on day 5 . The median urinary iodine on day 5 in full term neonates was 86 µg/l , which is markedly higher than the figure of 48 µg/L reported 15 years previously in neonates in the same area but still much lower than normal for this age group ( 150–200 µg/l ) . The mean iodine content of breast-milk was 78 µg/l , which is unchanged as compared to 15 years ago and is about 66 % of normal . Finally , the median urinary iodine increased from 60 µg/l on day 5 to 150 µg/l on day 30 in preterms bottle-fed with iodine-enriched formula-milk . Conclusion : the status of iodine nutrition has also improved spontaneously in Belgian neonates but has not yet normalised . Lactating and probably pregnant women remain clearly iodine deficient . The iodine-enriched formula-milk for preterms is efficient in correcting their iodine deficiency . National measures are urgently required for correction of iodine deficiency in Belgium OBJECTIVE To assess the iodine nutrition and thyroid function of pregnant women , lactating women and infants residing in areas where the Universal Salt Iodization program is in place . METHODS Pregnant women , lactating women and infants were selected r and omly in the regions where iodized salt coverage rate is more than 90 % since 2000 .  Urine iodine levels of pregnant woman , lactating woman and infants , milk iodine of lactating woman , thyroid-stimulating hormone ( TSH ) and free T4 of women were tested respectively . RESULTS Median Urinary Iodine ( MUI ) of infants , three groups of pregnant women ( first , second and third trimester ) and two groups lactating women ( breastfeeding less than or more than six months ) were 233 , 174 , 180 , 147 , 126 and 145 microg/L , respectively . Median milk iodine of lactating women was 163 microg/L. Percentage of milk iodine < 150 microg/L of early lactating women was 40 % less than that of late lactating women ( p < 0.01).There was a positive correlation between urine iodine of infants and milk iodine of lactating women ( r = 0.526 , p = 0.000 ) . T4 of two women were above or below the reference range . Total 15.4 % women 's TSH were abnormal . Most of these women 's urinary iodine were lower than 150 microg/L. CONCLUSION Iodine status of most of the target population for Universal Salt Iodization program is adequate , but iodine deficiency still existed in some . To assure every new life 's brain not be damaged by iodine deficiency , iodine status of targeted population s should be monitored and supplements provided according to the monitoring outcomes Endemic goitre has re-emerged in Thail and . This is particularly dangerous for children since iodine deficiency disorders ( IDDs ) might negatively influence their intellectual and mental development . In order to assess the situation , the iodine content of breast milk was determined and a method is proposed on how to monitor IDDs in lactating mothers later on . Seventy-five lactating women aged from 15 to 45 years , from 12 villages of 3 districts , namely Chumpae . Srichompu and Pupaman within the mountainous areas of Khon Kaen province , Northeast of Thail and were investigated . The breast milk from 46.7 per cent of mothers was found to be below recommended st and ards . In addition , 52.0 per cent of the women investigated had low urinary iodine excretion . The risk of women with low iodine excretion was 15 fold higher in comparison to women with sufficient iodine excretion to provide breast milk for their babies with insufficient iodine content . It is concluded that urinary iodine excretion can be used to monitor the IDDs in lactating mothers BACKGROUND Iodine deficiency in infancy can impair neurocognitive development , but there are few available indicators of iodine intake during this critical period . In many countries , access to newborns in maternity clinics in the first few days after birth is high . If spot urine sample s could be collected , reference data for urinary iodine concentration ( UIC ) would be useful to evaluate their iodine status . The study objectives were 1 ) to develop and vali date a simple pad system for collection of spot urine sample s for iodine ; 2 ) to establish a reference range for UIC in newborns in the first week after birth for use in monitoring iodine nutrition . METHODS A two-stage cluster sampling was used to obtain a representative national sample of healthy , term Swiss infants , 0 to 5 days old ( n = 634 ) .  Gestational information , whole blood for thyrotropin , and spot urine sample s on two consecutive days were collected . RESULTS The pad collection system was well-accepted and performed well during recovery and contamination testing . Median UIC in the total sample ( n = 1224 ) was 77 ( 95 % confidence interval ; 76 , 81 ) microg/L ; there was a gradual increase in median UIC within the range of 70 - 100 microg/L from days 1 through 4 . Because urinary creatinine concentrations were high and variable , the UI : creatinine ratio was not useful for st and ardization . CONCLUSIONS The current WHO median UIC cut-off ( > 100 microg/L ) for iodine sufficiency in infancy may be too high for the first week after birth . Reference data from iodine-sufficient newborns and a simple collection system may facilitate use of UIC as an indicator of iodine status in this age group 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 Adequate iodine concentration in breastmilk ( BMI C ) is essential for optimal neonatal thyroid hormone synthesis and neurological development in breastfed infants . For many decades , iodine deficiency has been a public health problem in Nepal . However , recently , excessive iodine intakes among Nepali infants have been reported . This study aim ed to measure BMI C and urinary iodine concentration ( UIC ) among lactating women in a peri-urban area of Nepal .  Iodine concentration was measured in spot urine ( n = 485 ) and breastmilk sample s ( n = 291 ) of 500 r and omly selected lactating women . The median ( p25 , p75 ) BMI C and median UIC were 250 ( 130 , 370 ) µg/L and 230 ( 135–377 ) µg/L , respectively . Around 82 % had BMI C > 100 µg/L , 61 % had BMI C > 200 µg/L and 81 % had UIC > 100 µg/L , 37 % had > 300 µg/L and 20 % had > 500 µg/L. In multiple linear regression models , time since birth ( β 3.0 , 95 % CI ( 0.2 , 5.0 ) ) and UIC ( β 1.0 , 95 % CI ( 0.1 , 2.0 ) ) were associated with BMI C , explaining 26 % of the variance . A large proportion of the women had adequate BMI C and UIC ; however , a subset had high iodine concentrations . These findings emphasize the importance of carefully monitoring iodine intake to minimize the risk of iodine excess and subsequently preventing transient iodine-induced hypothyroidism in breastfed infants 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 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 Growth and development of 207 children ( 49 % males ; mean age 5.4 years [ SD 0.2 ] , range 4 to 7.3 years whose mothers received iodine during pregnancy , and children who received iodine first in their 2nd year , were examined in 1996 ; 192 children ( 49 % males ; mean age 6.5 years [ SD 0.2 ] , range 5.8 to 6.9 years ) whose mothers received iodine while pregnant were seen in 1998 . Children were from the southern part of China 's Xinjiang Province which has the lowest levels of iodine in water and soil ever recorded .  Head circumference but not height was improved for those who received iodine during pregnancy ( compared with those receiving iodine at age 2 ) and for those supplemented before the end of the 2nd trimester ( relative to those supplemented during the 3rd trimester ) . Iodine before the 3rd trimester predicted higher psychomotor test scores for children relative to those provided iodine later in pregnancy or at 2 years . Results from the test for cognitive development result ed in trend only differences between those children supplemented during pregnancy versus later . The results address the question of when maternal iodine supplements should begin in public health programs world wide . Findings may be relevant to the treatment of maternal and newborn thyroid deficiency in industrialized countries , particularly for those infants delivered before the end of the second trimester 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 CONTEXT Iodine deficiency in utero impairs fetal growth , but the relationship between iodine deficiency and postnatal growth is less clear . OBJECTIVE The objective of the study was to determine whether iodine repletion improves somatic growth in iodine-deficient children and investigate the role of IGF-I and IGF binding protein (IGFBP)-3 in this effect . DESIGN , PARTICIPANTS , AND INTERVENTIONS Three prospect i ve , double-blind intervention studies were done : 1 ) in a 10-month study , severely iodine-deficient , 7- to 10-yr-old Moroccan children ( n = 71 ) were provided iodized salt and compared with children not using iodized salt ; 2 ) in a 6-month study , moderately iodine-deficient , 10- to 12-yr-old Albanian children ( n = 310 ) were given 400 mg iodine as oral iodized oil or placebo ; 3 ) in a 6-month study , mildly iodine-deficient 5- to 14-yr-old South African children ( n = 188 ) were given two doses of 200 mg iodine as oral iodized oil or placebo . At baseline and follow-up , height , weight , urinary iodine ( UI ) , total T4 ( TT4 ) , TSH , and IGF-I were measured ; in Albania and South Africa , IGFBP-3 was also measured . RESULTS In all three studies , iodine treatment increased median UI to more than 100 microg/liter , whereas median UI in the controls remained unchanged . In South Africa , iodine repletion modestly increased IGF-I but did not have a significant effect on IGFBP-3 , TT4 , or growth . In Albania and Morocco , iodine repletion significantly increased TT4 , IGF-I , IGFBP-3 , weight-for-age z scores , and height-for-age z scores . CONCLUSION This is the first controlled study to clearly demonstrate that iodine repletion in school-age children increases IGF-I and IGFBP-3 concentrations and improves somatic growth BACKGROUND Low levels of circulating thyroid hormones have been associated with poorer general and neurodevelopmental outcome in preterm babies and it has been speculated that the association is causal . Low levels of circulating thyroid hormone have been reported after inadequate intake of iodine in preterm infants being fed milk formula . AIM To investigate whether increased iodine intake from supplemented preterm formula would improve thyroid hormone levels in preterm babies ( this study ) and hence improve neurodevelopmental status ( planned subsequent study ) . METHOD A total of 121 preterm infants were entered into a r and omised controlled trial of st and ard ( 68 μg/l ) versus increased ( 272 μg/l ) iodine in preterm formula . RESULTS The two groups were comparable at recruitment . No evidence of an effect of the intervention on thyroid hormone levels was seen up to 41 weeks after conception . CONCLUSION Calls for increased iodine content of preterm infant formulas are not justified by this study . Key message Increasing milk iodine content in line with the latest recommendations for preterm babies had no effect on thyroid hormone levels in the perinatal BACKGROUND Iodine deficiency ( even moderate ) plays a major role in pregnancy associated goiter development , which is only party reversible after pregnancy . The prevalence of post partum thyroiditis is reported to be slightly lower in areas of iodine deficiency . Thus iodine supplementation may be effective in decreasing pregnancy associated increase in thyroid volume , but enhances the risk of increasing the prevalence of thyroid dysfunction in the post partum period . Therefore , we evaluated the effect of iodine supplementation ( with two different doses : 50 microg and 250 microg ) on the prevalence of post partum thyroiditis and the decrease in thyroid volume up to 8 months post partum in an area of mild iodine deficiency . PATIENTS AND METHODS Thyroid volume of 56 women was evaluated 5 days and 3 months after delivery ( study I ) . In an intervention study ( Study II ) 70 women were r and omized to receive 50 or 250 microg of potassium iodide for a period of 8 months post partum beginning five days after delivery . Thyroid volume , the echogenecity of the thyroid gl and , thyroid hormone parameters ( T4 , T3 , fT4 , TSH ) and thyroid antibodies ( TPO and Tg-Ab ) were measured 5 days , 3 and 8 months after delivery . RESULTS A total number of 11 women developed postpartum thyroid dysfunction : 4 women developed manifest thyroid dysfunction ( 3 hyperthyroidism and 1 hypothyroidism ) 3 months post partum . The remaining seven had sub clinical hypo- or hyperthyroidism . All changes were clinical ly mild and transient as evidence d by normalization of thyroid hormone parameters on reexamination at 8 months . Among the eleven , 6 women in the 50 microg iodine group and 5 women of the 250 microg iodine group developed thyroid dysfunction , suggesting that the iodine dose did not affect post partum thyroiditis . The administration of only 50 microg iodine was associated with a significant fall of thyroid size already 3 months after delivery ( 25.4 + /- 1.5 ml ( mean + /- sem ) to 18.2 + /- 1.25 p < 0.001 ) . The application of 250 microg iodine was equally effective . 8 months post partum a slight but further decrease could be demonstrated . On the other h and , in study I no significant reduction in thyroid volume was observed in women receiving no supplementary iodine ( thyroid volume at delivery 29 + /- 2.2 ml ; at 3 months 27.5 + /- 3.0 ml . CONCLUSION The administration of supplementary iodine ( up to 250 microg ) to an unselected population , residing in an area of mild iodine deficiency , in the post partum period is save as indicated by a prevalence of 5.7 % manifest thyroid dysfunction . These changes are clinical ly mild and transient . Even the amount of 50 microg of iodine supplementation seems to by very efficient in reducing pregnancy associated increments in thyroid volume
The results are thus compatible with the international recommendation that lactating women and infants younger than two years of age who reside in iodine-sufficient countries do not require iodine supplementation
BACKGROUND Iodine , an essential micronutrient , plays a critical role in normal growth and development , especially during the first two years of life .
This systematic review and meta- analysis is among the first to evaluate breast-milk iodine concentrations and infant iodine status in countries characterized by iodine sufficiency or deficiency .