Iodine Supplementation In Pregnant Women Research Articles

Evaluation of Iodine Supplementation in Pregnant Women with Gestational Diabetes: IODIAB Study.

Iodine supplementation is indicated by the French National Authority for Health (HAS) and the World Health Organization (WHO) during pregnancy. This study investigates whether this supplementation is consistently prescribed in line with WHO recommendations in pregnant women diagnosed with gestational diabetes mellitus. A total of 99 women with a diagnosis of gestational diabetes were included in the study and were all closely monitored. Only 17 (17.2%) patients received the recommended iodine supplementation. The follow-up, whether conducted by a gynecologist or midwife, did not influence the prescription of iodine supplements. By contrast, 72 (72.7%) of patients received folic acid supplementation. The prescription of iodine supplementation for the pregnant women included in our study is insufficient. Few practitioners seem aware of the recommendations, even when the pregnancy is complicated by gestational diabetes.

Nutritional Status of Iodine in a Group of Pregnant Women from the State of Minas Gerais Correlated with Neonatal Thyroid Function.

To evaluate the iodine sufficiency of pregnant women assisted in a University Hospital of Minas Gerais, and to correlate the urinary concentrations of maternal iodine with the fetal thyroid hormone levels at birth. Urinary iodine concentrations from 30 pregnant women with a singleton pregnancy and gestational age lower than 20 weeks were analyzed. Occasional samples of the mothers' urine were collected for the urinary iodine concentration dosage, and these were correlated with the newborns' thyroid-stimulating hormone (TSH) levels. The median iodine urinary concentration of this study's pregnant women population was 216.73 mcg/l, which is proper for the group, following the World Health Organization (WHO). No cases of neonatal hypothyroidism were reported in the study, which corroborates the iodine sufficiency in this population sample. This study shows that despite the increased demand for iodine from pregnant women and the Brazilian Health Regulatory Agency (ANVISA) recommendation of 2013 for reduction of salt iodization levels, the population of pregnant women attended in the prenatal ambulatory of normal risk from the Federal University of Minas Gerais is considered sufficient in iodine. As a higher sample is necessary for the confirmation of these findings, it is too early to recommend the universal supplementation of iodine for Brazilian pregnant women, and more studies must be carried out, considering that iodine supplementation for pregnant women in an area of iodine sufficiency is associated to the risks of the fetus's excessive exposure to iodine.

Iodine Supplementation in Pregnancy in an Iodine-Deficient Region: A Cross-Sectional Survey.

Iodine deficiency is a common problem in pregnant women and may have implications for maternal and child health. Iodine supplementation during pregnancy has been recommended by several scientific societies. We undertook a cross-sectional survey to assess the efficacy of these recommendations in a European iodine-deficient region. Urinary iodine concentrations (UIC) were determined in pregnant women before (n = 203) and after (n = 136) the implementation of guidelines for iodine supplementation in pregnancy. Iodine supplementation (200 μg/day) reduced the proportion of pregnant women with severe iodine deficiency (37.4% to 18.0%, p = 0.0002). The median UIC increased from 67.6 µg/L to 106.8 µg/L but remained below the recommended target level (>150 µg/L) for pregnant women. In conclusion, iodine supplementation in pregnant women improved iodine status in this iodine-deficient region but was insufficient to achieve recommended iodine levels in pregnancy. Additional measures, such as the adjustment of the dose or timing of supplementation, or universal salt iodization, may be needed.

Iodine Supplementation in Pregnant Women with Hashimoto's Thyroiditis

Iodine Supplementation in Pregnant Women with Hashimoto's Thyroiditis

Mild to moderate iodine deficiency in pregnancy: A matter of debate

During the last few decades painstaking efforts have been made to eliminate iodine deficiency through the world. Nowadays in regions where dietary iodine intake is adequate or borderline, the main focus is increasing dietary iodine supply in the target population during pregnancy and the first years of life. Severe iodine deficiency during pregnancy increases the risk of irreversible brain damage, intellectual disability, neurologic abnormalities, stunted growth, increased pregnancy loss, infant mortality, impairments in child development and cretinism. The potential effects of mild-to-moderate iodine deficiency are debated. Results from animal studies and observational human studies indicate that maternal mild-to-moderate iodine deficiency disturbs thyroid function in pregnancy and it also may affects fetal neurodevelopment. The effect of supplementation of iodine on thyroid function of pregnant women and their newborn, neurodevelopment of infants and cognitive performance of children have been investigated using iodine nutrition in pregnancy, based on median urinary iodine concentration. However they have found conflicting results regarding the benefits or harms of iodine supplementation in pregnancy. Although many epidemiological, interventional and clinical studies have supported the association between thyroid function in pregnant women and later psychomotor and mental development of their children, the effect of iodine supplementation in pregnant women on neurodevelopment of children is inconclusive. Even in areas with well-established universal salt iodization program, pregnancy could be at risk of having iodine deficiency and despite WHO/ICCIDD/UNICEF recommendation which believe that dietary iodine fortification during pregnancy depends primarily on the extent of pre-existing iodine deprivation, systematic dietary fortification needs to be implemented in this vulnerable group. However, iodine supplementation of mildly iodine deficient pregnant women may not have beneficial effects in their thyroid function or neurodevelopment of their children.

Iodine supplementation for pregnant women: a cross-sectional national interventional study.

Although Iran has been considered iodine replete since 2000, the first national survey of iodine intake among Iranian pregnant women in 2014 indicated that despite the adequate intake of iodine by the general population, this vulnerable group has moderate iodine deficiency. Therefore, in this national cross-sectional interventional study, we aimed to assess the iodine intake and thyroid function of Iranian pregnant women 2 years after implementing national iodine supplementation for this vulnerable group. In this cross-sectional study, we conducted a national interventional survey of pregnant women. A total of 1200 pregnant women (400 women from each trimester) from 12 provinces of Iran were recruited from the antenatal care clinics from October 2018 to March 2019. The median urinary iodine concentration (MUIC), as an indicator of iodine status in three spot urine samples, was measured, along with the serum total T4 (TT4), thyrotropin (TSH), thyroglobulin (Tg), thyroid peroxidase antibody (TPO-Ab), and iodine content of household salt. The mean age of the cohort was 28 ± 6.2years, with the mean gestational age of 22.7 ± 13.0weeks. The overall MUIC (IQR) of pregnant women was 188µg/L (124.2-263µg/L). Also, the MUICs in the three trimesters of pregnancy were 174µg/L (110-254), 175µg/L (116-251), and 165µg/L (114-235), respectively. The MUICs ≥ 150, 100-149, and < 100µg/L were found in 63, 19.8, and 16.2% of the subjects, respectively. The mean TT4 level was 12 ± 4.5µg/dL, and the median (IQR) level of TSH was 2.37 mIU/L (1.66-3.18 mIU/L). According to our local reference range, 118 (10.5%) pregnant women had subclinical hypothyroidism, 6 (0.53%) women had isolated hypothyroxinemia, and 65 (5.7%) women were TPO-Ab positive. Also, the median (IQR) level of Tg was 10.08µg/dL (5.7-20.4µg/dL), and the median iodine content of household salt was 29.6µg/g; the iodine content was ≥ 30µg/g in 85% of household salt. The results showed that more than 95% of households were under iodized salt coverage. The results of this study indicated that iodine supplementation with at least 150µg of iodine per day improved the iodine intake of pregnant women. Except for subclinical hypothyroidism, the prevalence of clinical hypothyroidism, clinical/subclinical thyrotoxicosis, TPO-Ab positivity, and isolated hypothyroxinemia decreased significantly, which emphasizes the importance of iodine supplementation during pregnancy.

Is It Necessary to Recommend Iodine Supplement to Pregnant Women Living in Areas with Adequate Iodine Intake?

Background: Iodine need is increased during pregnancy and its deficiency can lead to complications in mother and fetus. The latest international guidelines have recommended a higher intake of iodine. Iran has implemented a national salt iodization program since 25 years ago, and the general population is iodine-sufficient. However, recent studies have shown that a significant proportion of pregnant women have urinary iodine concentration (UIC) below the recommended range of 150 - 250 µg/L. Based on the results of these studies, iodine supplement during pregnancy is widely used, but this practice is controversial. Objectives: The aim of this study was to evaluate the necessity for iodine supplementation in pregnant women living in Shiraz, an iodine-replete area. Methods: In this cross-sectional case-control study, UIC and thyroid-stimulating hormone of 174 pregnant women taking 150 µg/day iodine (group 1) were compared with 124 pregnant women not taking the supplement (group 2). The proportion of women with UIC below the recommended level in each group was also determined. UIC of the women in different trimesters in each group was also investigated and compared. Results: Mean UIC in groups 1 and 2 was 175.71 ± 56.43 µg/L and 122.5 ± 44.37 µg/L and this difference was significant (P = 0.006). Also, 56% of women in group 2 and 24 % in group 1 had UIC below the recommended value (P &lt; 0.01). Mean UIC in both groups decreased with advancing gestational age. In group 1, mean UIC remained in the recommended range, whereas in group 2, it decreased to less than 100 µg/L. Conclusions: In areas covered by the national salt iodine implementation program, it is necessary to recommend iodine supplement to pregnant women to prevent iodine insufficiency.

Comparison of the Effectiveness of Universal and Targeted Iodine Supplementation in Pregnant Women: A Randomized Controlled Trial

Objective: To compare the effectiveness of universal and targeted iodine supplementation strategies. Methods: A randomized controlled trial involving low-risk Thai pregnant women was carried out. The participants were categorized into either the study group, in which iodine supplementation was varied based on median urine iodine concentration, or the control group, which received universal supplementation. Urine samples were collected before the start of treatment and at delivery. The primary outcome was iodine status after each supplementation regime. Results: Two hundred and eight women were randomly categorized into 2 groups, 104 control-group participants and 104 study-group participants. Baseline iodine status in both groups was not significantly different. More than half of the pregnant women were classified as having iodine insufficiency. After supplementation, the proportions of iodine insufficiency in the control and study groups (27.9 and 33.3%, respectively; p value = 0.508) and those of excessive level (19.1 and 11.7%, respectively; p value = 0.247) were not significantly different between the 2 groups. However, iodine level above the requirement was statistically significantly higher in the control group (47.1%) compared with the study group (30.0%; p value = 0.048). Conclusions: The 2 strategies, universal and targeted supplementation, have comparable effectiveness in prevention of iodine deficiency, but the evidence suggests that targeted supplementation is better in avoiding over-supplementation.

The Effect of Iodine-Containing Vitamin Supplementation During Pregnancy on Thyroid Function in Late Pregnancy and Postpartum Depression in an Iodine-Sufficient Area.

The purpose of this study was to investigate the effect of iodine supplementation during pregnancy on thyroid function and also its effect on postpartum depression in an iodine-sufficient area. Healthy pregnant women were divided into three groups: group A (vitamin iodine-150) receiving vitamin containing 150μg iodine, group B (vitamin iodine-0) receiving vitamin without iodine, and group C (no vitamin) receiving no vitamin. General information was collected by questionnaire and thyroid function was determined in the third trimester of pregnancy. Depression was assessed 1month postpartum by the Edinburgh postnatal depression scale (EPDS). The results showed that there was no significant difference in thyroid-stimulating hormone (TSH) level among the three groups (P > 0.05). FT4 concentration was significantly lower in group A (n= 234: 10.68pmol/L) than in group B (n= 220: 11.47pmol/L) and group C (n= 195: 11.64pmol/L) (P < 0.05), However, it was still within the normal range. EPDS scores obtained from group B (3.50) and group C (3.00) were similar but markedly lower than group A (5.00) (P < 0.05). Despite the difference in the EPDS score, the prevalence of postpartum depression was not significantly different among the three groups. In conclusion, 150μg/day iodine supplementation for pregnant women in areas with adequate iodine had little effect on thyroid function in the third trimester, and serum FT4 level could not be increased. Iodine supplementation during pregnancy also had no significant effect on postpartum depression.

Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial

Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial

The effectiveness of iodine supplementation during pregnancies in geographical areas of high prevalence of iodine insufficiency

The objective of this study was to determine the effectiveness of routine iodine supplementation among pregnant women in areas of high prevalence of an iodine insufficiency, using WHO criteria to determine the iodine status. A longitudinal study was conducted on pregnant women attending antenatal care at a tertiary hospital. The urine iodine concentration was measured in the first trimester and after 150 μg of iodine supplementation in the third trimester. A total of 327 pregnant women met the inclusion criteria with a complete follow-up. The prevalence of an iodine insufficiency was significantly lower in the third trimester, when compared to the first trimester (21.41% vs 55.35%, p < .001). However, 21.4% of cases still had an iodine insufficiency and 35.17% had an ‘above-requirement’ in the third trimester. In the areas of high prevalence of iodine insufficiency, an iodine supplementation significantly reduces the number of women with insufficiency; however, it was associated with unnecessarily high UICs, leading to the risk of excess iodine.Impact statementWhat is already known on this subject: Iodine insufficiency is highly prevalent in many geographical areas. Half of the pregnant women in the northern part of Thailand had an iodine insufficiency in the first trimester.What do the results of this study add: Iodine supplementation (daily 150-mcg of potassium iodide) could significantly reduce the number of women with the insufficiency. About one-fifth of women still had an iodine insufficiency in spite of iodine supplementation. Universal supplementation could be associated with unnecessarily high UICs, potentially at risk of iodine excess.What are the implications of these findings for clinical practice and/or further research: Physicians should guard against the occurrence of adverse effect from an iodine excess when there is routine iodine supplementation for pregnant women. Further study is required to establish the best strategy for an iodine supplementation in pregnancy.

Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial

Iodine deficiency during pregnancy might be associated with reduced intelligence quotient (IQ) score in offspring. We assessed the effect of iodine supplementation in mildly iodine-deficient pregnant women on neurodevelopment of their offspring in areas where schoolchildren were iodine sufficient. In this randomised, placebo-controlled trial, pregnant women in Bangalore, India, and Bangkok, Thailand, were randomly assigned (1:1) to receive 200 μg iodine orally once a day or placebo until delivery. Randomisation was done with a computer-generated sequence and stratified by site. Co-primary outcomes were verbal and performance IQ scores on the Wechsler Preschool and Primary Scale of Intelligence Third Edition (WPPSI-III) and the global executive composite score from the Behaviour Rating Inventory of Executive Function-Preschool Version (BRIEF-P) in the children at age 5-6 years. The trial was double-blinded; some unmasking took place at age 2 years for an interim analysis, but participants and nearly all investigators remained masked to group assignment until age 5-6 years. Analysis was by intention to treat using mixed-effects models. This trial is registered with ClinicalTrials.gov, number NCT00791466. Between Nov 18, 2008, and March 12, 2011, 832 women entered the trial at a mean gestational age of 10·7 weeks (SD 2·7); median urinary iodine concentration was 131 μg/L (IQR 81-213). Mean compliance with supplementation was 87%, assessed by monthly tablet counts. 313 children (iodine group, n=159; placebo group, n=154) were analysed for verbal and performance IQ with WPPSI-III and 315 (iodine group, n=159; placebo group, n=156) for overall executive function with BRIEF-P. Mean WPPSI-III scores for verbal IQ were 89·5 (SD 9·8) in the iodine group and 90·2 (9·8) in the placebo group (difference -0·7, 95% CI -2·9 to 1·5; p=0·77), and for performance IQ were 97·5 (12·5) in the iodine group and 99·1 (13·4) in the placebo group (difference -1·6, -4·5 to 1·3; p=0·44). The mean BRIEF-P global executive composite score was 90·6 (26·2) in the iodine group and 91·5 (27·0) in the placebo group (difference -0·9, -6·8 to 5·0; p=0·74). The frequency of adverse events did not differ between groups during gestation or at delivery: 24 women in the iodine group and 28 in the placebo group reported adverse events (iodine group: abortion, n=20; blighted ovum, and n=2; intrauterine death, n=2; placebo group: abortion, n=22; blighted ovum, n=1; intrauterine death, n=2; early neonatal death, n=1; and neonatal death, n=2). Daily iodine supplementation in mildly iodine-deficient pregnant women had no effect on child neurodevelopment at age 5-6 years. Swiss National Science Foundation, Nestlé Foundation, Wageningen University and Research, and ETH Zurich.

Statistical design considerations applicable to clinical trials of iodine supplementation in pregnant women who may be mildly iodine deficient

No large, randomized, placebo-controlled trial of iodine supplementation in pregnant women in a region of mild or moderate iodine deficiency has been completed in which a primary outcome measure was an assessment of the neurobehavioral development of the offspring at age ≥2 y. In this article, I discuss considerations for the design of such a trial in a region of mild iodine deficiency, with a focus on statistical methods and approaches. Exposure and design issues include the ethics of using a placebo, the potential for overexposure to iodine, and the possibility of community randomization. The main scientific goal of the trial is important in determining the follow-up period. If the goal is to determine whether iodine supplementation during pregnancy improves neurobehavioral development in the offspring, then follow-up should continue until a reasonably reliable assessment can be conducted, which might be at age ≥2 y. Once the timing of assessment is decided, the impact of potential loss to follow-up should be considered so that appropriate statistical methods can be incorporated into the design. The minimum sample size can be calculated by using a sample size formula that incorporates noncompliance and assumes that a certain proportion of study participants do not have any outcome observed. To have sufficient power to detect a reasonably modest difference in neurobehavioral development scores using an assessment tool with an SD of 15, a large number of participants (>500/group) is required. The minimum adequate number of participants may be even larger (>1300/group) depending on the magnitude of the difference in outcome between the supplementation and placebo groups, the estimated proportion of the iodine-supplementation group that fails to take the supplement, and the estimated proportion of pregnancies that do not produce outcome measurements.

Costs and benefits of iodine supplementation for pregnant women in a mildly to moderately iodine-deficient population: a modelling analysis

Results from previous studies show that the cognitive ability of offspring might be irreversibly damaged as a result of their mother's mild iodine deficiency during pregnancy. A reduced intelligence quotient (IQ) score has broad economic and societal cost implications because intelligence affects wellbeing, income, and education outcomes. Although pregnancy and lactation lead to increased iodine needs, no UK recommendations for iodine supplementation have been issued to pregnant women. We aimed to investigate the cost-effectiveness of iodine supplementation versus no supplementation for pregnant women in a mildly to moderately iodine-deficient population for which a population-based iodine supplementation programme--for example, universal salt iodisation--did not exist. We systematically searched MEDLINE, Embase, EconLit, and NHS EED for economic studies that linked IQ and income published in all languages until Aug 21, 2014. We took clinical data relating to iodine deficiency in pregnant women and the effect on IQ in their children aged 8-9 years from primary research. A decision tree was developed to compare the treatment strategies of iodine supplementation in tablet form with no iodine supplementation for pregnant women in the UK. Analyses were done from a health service perspective (analysis 1; taking direct health service costs into account) and societal perspective (analysis 2; taking education costs and the value of an IQ point itself into account), and presented in terms of cost (in sterling, relevant to 2013) per IQ point gained in the offspring. We made data-supported assumptions to complete these analyses, but used a conservative approach that limited the benefits of iodine supplementation and overestimated its potential harms. Our systematic search identified 1361 published articles, of which eight were assessed to calculate the monetary value of an IQ point. A discounted lifetime value of an additional IQ point based on earnings was estimated to be £3297 (study estimates range from £1319 to £11,967) for the offspring cohort. Iodine supplementation was cost saving from both a health service perspective (saving £199 per pregnant woman [sensitivity analysis range -£42 to £229]) and societal perspective (saving £4476 per pregnant woman [sensitivity analysis range £540 to £4495]), with a net gain of 1·22 IQ points in each analysis. Base case results were robust to sensitivity analyses. Iodine supplementation for pregnant women in the UK is potentially cost saving. This finding also has implications for the 1·88 billion people in the 32 countries with iodine deficiency worldwide. Valuation of IQ points should consider non-earnings benefits--eg, health benefits associated with a higher IQ not germane to earnings. None.

A review of the iodine status of UK pregnant women and its implications for the offspring.

Iodine, as a component of the thyroid hormones, is crucial for brain development and is therefore especially important during pregnancy when the brain is developing most rapidly. While randomised controlled trials of pregnant women in regions of severe iodine deficiency have shown that prenatal iodine deficiency causes impaired cognition, less is known of the effects in regions of mild deficiency. This is relevant to the UK as the World Health Organisation now classifies the UK as mildly iodine deficient, based on a national study of 14-15 year old schoolgirls in 2011. We have previously published a study using samples and data from the UK-based Avon Longitudinal Study of Parents and Children (ALSPAC) that found an association between low iodine status in early pregnancy (urinary iodine-to-creatinine ratio <150 μg/g) and lower verbal IQ and reading scores in the offspring. Though the women in ALSPAC were recruited in the early 1990s, the results of the study are still relevant as their iodine status was similar to that reported in recent studies of UK pregnant women. This review discusses the evidence that mild-to-moderate iodine deficiency during pregnancy has deleterious effects on child neurodevelopment and relates that evidence to the data on iodine status in the UK. It has highlighted a need for nationwide data on iodine status of pregnant women and that a randomised controlled trial of iodine supplementation in pregnant women in a region of mild-to-moderate iodine deficiency with child outcomes as the primary endpoint is required.

Inadequate status of iodine nutrition among pregnant women residing in three districts of Niamey, the Niger Republic's capital.

Universal dietary salt iodisation (UDSI) programme was implemented in Niger in 1996. However, since 2000, there has been a slowdown in progress against iodine deficiency. The aim of our study was to assess the iodine status among pregnant women in a context where national controls are not effective at ensuring universal availability of adequately iodised salt. This is mainly to assess the impact of the slowdown in the fight against iodine deficiency in this vulnerable group. The study was centred on 240 healthy pregnant women volunteers recruited in three districts primary health centres. A control group of 60 non-pregnant, non-lactating healthy women was also studied and compared. Median urinary iodine concentration (UIC) of all pregnant women was 119 μg L(-1) , and 61.67% had UIC below 150 μg L(-1) . Median UIC for the first, second and third trimester were 144, 108 and 92 μg L(-1) , respectively. The percentage of pregnant women with UIC below 150 μg L(-1) increased from 52% in the first trimester to 66% in the third trimester. The median UIC of the control group was 166 μg L(-1) , and 28.33% had UIC below 100 μg L(-1) . No significant relationship was found between nutritional iodine status and provenance, age and parity. However, significant relationship was found between iodine status and stage of pregnancy, gestational age and educational level (P < 0.05). Iodine nutrition status thus observed was inadequate in 61.67% of all the pregnant women. It is therefore urgent to revitalise implementation of the UDSI programme, and in the short term to consider iodine supplementation for pregnant women.

Gestational changes of thyroid function and urinary iodine in thyroid antibody-negative Japanese women

Iodine is an essential nutrient for thyroid hormone synthesis, and iodine deficiency especially in pregnant and lactating women results in serious damage to their infants. To characterize iodine nutrition throughout gestation by using a food frequency questionnaire (FFQ) and urinary iodine concentration (UIC) measurement, and to establish appropriate gestational age-specific reference ranges for serum TSH and FT₄ in thyroid autoantibody (ThAb) negative euthyroid Japanese women, a total number of 563 pregnant women including 422 subjects with negative ThAbs, 105 postpartum women and their 297 newborn infants were included in the study. Dietary iodine intake (DII) was evaluated by FFQ. Serum TSH, FT₄ and UIC were sequentially determined in the three trimesters of pregnancy and at the 31st postpartum day. The overall median UICs throughout pregnancy and in the postpartum period were 224.0 and 135.0 μg/L, respectively, suggesting sufficient iodine nutrition. The median DII was 842.4 μg/day in pregnant women. The median UIC in the first trimester (215.9 μg/L) significantly decreased in the second trimester (136.0 μg/L). The prevalence of pregnant women with a UIC below 150 μg/L was 31.6% and that in lactating women with a UIC below 100 μg/L was 33.3%. The pattern of gestational change in serum TSH and FT₄ was comparable to that in iodine-sufficient areas. A substantial percentage of women might be at risk for iodine deficiency if there is a restriction of iodine-rich foods. However, iodine supplementation for pregnant women must be carefully balanced against the risk of iodine excess particularly in Japan. Further research in larger samples is needed.

Thyroid (dys-)function in normal and disturbed pregnancy

During pregnancy, physiologic changes in maternal thyroid function take place especially due to hormonal as well as metabolic processes. Human chorionic gonadotropin activates the maternal thyroid gland leading to increased thyroid hormone production. A sufficient availability of maternal thyroid hormones is essential for fetal development, especially during the first trimester of pregnancy, when the fetal thyroid gland is not yet functional. Current knowledge of thyroid dysfunction including thyroid autoimmunity, hypothyroidism or hyperthyroidism is summarized with special focus on miscarriage and pregnancy disorders. Therefore, a Medline research as well as an analysis of current guidelines on thyroid function and pregnancy was performed. A study focusing on TSH levels in normal and disturbed pregnancies, the risk of miscarriage in association with thyroid autoantibodies, and (subclinical) hypothyroidism in infertile and fertile women were included. Maternal thyroid dysfunction negatively affects pregnancy outcome. Besides a routine iodine supplementation in pregnant women and treatment of hypo as well as hyperthyroidism, TSH levels should routinely be measured in women during childbearing years and adjusted to concentrations <2.5 mIU/l in order to optimize maternal health and fetal development.

Iodine deficiency in pregnancy and in women of reproductive age in Erzurum, Turkey

Aim: Iodine deficiency (ID) is an important public health problem and the most common cause of preventable mental retardation. The aims of this study were to determine the urinary iodine concentration (UIC) of pregnant women living in Erzurum, to assess the ID rate, and to find out whether iodine supplementation is necessary in pregnancy. Materials and methods: Spot urine was obtained from pregnant and nonpregnant women with no functional or organic thyroid disease. The UIC was studied using the Sandell-Kolthoff method. Results: The median UIC values of pregnant women in the first, second, and third trimesters and of the nonpregnant women were 126.0, 134.6, 132.7, and 137.3 µg/L, respectively. The total ID rate was 72.6% and 18.0% in the pregnant and the nonpregnant women, respectively. Conclusion: The ID rate in pregnancy was found to be high in Erzurum. ID rates were highest in the first trimester, when fetal neurodevelopment is most affected. ID is still a serious problem in Erzurum despite mandatory salt iodization. However, the fact that the deficiency is mild to moderate is promising as regards the potential response to iodine supplementation in pregnant women.

What Do We Know about Iodine Supplementation in Pregnancy?

Despite major progress over the last four decades, iodine deficiency remains the leading preventable cause of mental retardation. It has been estimated that 20% of the 2 billion individuals worldwide currently at risk for iodine deficiency disorders reside in Europe (1). The study of Velasco et al. (2), published in this issue of JCEM, demonstrated that infants of Spanish mothers who had received oral 300 g potassium iodide (KI) supplements daily during pregnancy and lactation had higher Bayley Psychomotor Development scores at 3–18 months of age than infants whose mothers did not receive iodine supplements. A strength of the study was the authors’ ability to collect trimester-specific urinary iodine concentrations (UIC) and thyroid function data, cord blood thyroid function studies, infant UIC, breast milk iodine concentrations, and infant neurocognitive data in a majority of the treatment group; this was a heroic feat. The major limitation of the study is the fact that it was not rigorously controlled. Apparently this was not by choice. The authors note that “the Ethics Committee . . . did not authorize the inclusion of a control group without treatment.” The authors selected a group of 61 untreated women to serve as controls. Because they were enrolled in the eighth month of pregnancy, thyroid function and urinary iodine measurements were not obtained in these women before the third trimester. Another 31 untreated women who experienced miscarriage at wk 8–12 were recruited to provide only UIC. Although there was no difference between treated and untreated groups in infant birth weights, Apgar scores, maternal age, frequency of prematurity, frequency and duration of breastfeeding, or parental education, neurodevelopment is an extremely complex process, and there are many potential confounders that could have contributed to the apparent difference in infant development between the study groups. Was the decision of the Ethics Committee appropriate? It would clearly be unethical to withhold iodine supplementation from pregnant women known to be severely iodine deficient. A blinded, placebo-controlled clinical trial begun in the 1960s in Papua, New Guinea, demonstrated that preconception supplementation of severely iodine-deficient women (median UIC 20 g/liter) with iodinated oil eliminated the risk for cretinism and improved offspring cognitive function and survival (3). These findings have subsequently been replicated in many regions of the world (4). A meta-analysis of Chinese studies suggests that iodine supplementation in severely iodinedeficient regions may increase the average child IQ by 12.5 points (5). The women in the Velasco study, however, were moderately but not severely iodine deficient at baseline. Although sample sizes were small, in the two untreated control groups, the median UIC were 69 and 88 g/liter—both below the optimal range of 150–249 g/liter as defined by the World Health Organization (6), and similar to the UIC of 84 g/liter previously reported for third-trimester pregnant women from Andalusia (7). What is known about the effects of iodine supplementation in pregnant women with this moderate degree of iodine deficiency? Seven previous controlled trials of iodine supplementation in moderately iodine-deficient pregnant European women have been published, although doses and timing of iodine supplementation varied, and only one previous trial examined effects on offspring development.