Women Remain at Risk of Iodine Deficiency during Pregnancy: The Importance of Iodine Supplementation before Conception and Throughout Gestation

In Australia, pregnant women are advised to take an iodine supplement (I-supp) (150 µg/day) to reduce risks to the foetus associated with iodine deficiency (ID). To examine the impact of this recommendation on iodine status, and to identify factors that contribute to adequacy during gestation, supplement use and Urinary Iodine Concentration (UIC) was measured in 255 pregnant women (gestation range 6 to 41 weeks) in Tasmania. The median UIC (MUIC) of 133 µg/L (Inter-quartile range 82–233) was indicative of ID, being below the 150–249 µg/L range for adequacy during pregnancy. Women taking an iodine-containing-supplement (I-supp) had a significantly higher MUIC (155 µg/L) (n = 171) compared to the combined MUIC (112.5 µg/L) (n = 84) of those who had never (120 µg/L) (n = 61) or were no longer taking an I-supp (90 µg/L) (n = 23) (p = 0.017). Among women reporting I-supp use, the MUIC of those commencing the recommended 150 µg/day prior to conception was significantly higher than those starting supplementation following pregnancy confirmation: 196 (98–315) µg/L (n = 45) versus 137.5 (82.5–233.5) µg/L (n = 124), p = 0.032. Despite recommendations for iodine supplementation pregnant Tasmanian women remain at risk of ID. Commencing an I-supp of 150 µg/day prior to conception and continuing throughout pregnancy is required to ensure adequacy. Timely advice regarding the importance of adequate iodine nutrition, including supplementation is needed to reduce the risk of irreversible in utero neurocognitive damage to the foetus.

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

Archive of Food and Nutritional Science ◽

10.29328/journal.afns.1001028 ◽

2021 ◽

Vol 5 (1) ◽

pp. 018-026

Author(s):

Delshad Hossein ◽

Azizi Fereidoun

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Iodine Supplementation ◽

Iodine Deficiency In Pregnancy ◽

In Pregnancy

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.

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High Iodine Deficiency among Pregnant Women in Periurban Ghana: A Hospital-Based Longitudinal Study

Journal of Nutrition and Metabolism ◽

10.1155/2018/9706805 ◽

2018 ◽

Vol 2018 ◽

pp. 1-5

Author(s):

David Larbi Simpong ◽

Yaw Asante Awuku ◽

Kenneth Kwame Kye-Amoah ◽

Martin Tangnaa Morna ◽

Prince Adoba ◽

...

Keyword(s):

Longitudinal Study ◽

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Clinical Information ◽

Iodine Concentration ◽

Iodized Salt ◽

Urinary Iodine Concentration ◽

Study Cohort ◽

Iodine Sufficiency

Background. Iodine deficiency causes maternal hypothyroidism which can lead to growth, cognitive, and psychomotor deficit in neonates, infants, and children. This study examined the iodine status of pregnant women in a periurban setting in Ghana. Methods. This longitudinal study recruited 125 pregnant women by purposeful convenience sampling from the antenatal clinic of the Sefwi Wiawso municipal hospital in Ghana. Urinary iodine concentration (UIC) was estimated by the ammonium persulfate method at an estimated gestational age (EGA) of 11, 20, and 32 weeks. Demographic information, iodized salt usage, and other clinical information were collected using a questionnaire. Results. The prevalence of iodine deficiency among the pregnant women was 47.2% at EGA 11 and 60.8% at both EGA of 20 and 32, whereas only 0.8% of participants not using iodized salt had iodine sufficiency at EGA 32. 18.4%, 20%, and 24% of participants using iodized salt had iodine sufficiency at EGA 11, 20, and 32, respectively. Conclusion. A high prevalence of iodine deficiency was observed among our study cohort.

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Iodine status of consumers of milk-alternative drinks v. cows’ milk: data from the UK National Diet and Nutrition Survey

British Journal Of Nutrition ◽

10.1017/s0007114520003876 ◽

2020 ◽

pp. 1-9

Author(s):

M. Dineva ◽

M. P. Rayman ◽

S. C. Bath

Keyword(s):

At Risk ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Nutrition Survey ◽

Iodine Status ◽

Adults And Children ◽

The Uk

Abstract Milk is the main source of iodine in the UK; however, the consumption and popularity of plant-based milk-alternative drinks are increasing. Consumers may be at risk of iodine deficiency as, unless fortified, milk alternatives have a low iodine concentration. We therefore aimed to compare the iodine intake and status of milk-alternative consumers with that of cows’ milk consumers. We used data from the UK National Diet and Nutrition Survey from years 7 to 9 (2014–2017; before a few manufacturers fortified their milk-alternative drinks with iodine). Data from 4-d food diaries were used to identify consumers of milk-alternative drinks and cows’ milk, along with the estimation of their iodine intake (µg/d) (available for n 3976 adults and children ≥1·5 years). Iodine status was based on urinary iodine concentration (UIC, µg/l) from spot-urine samples (available for n 2845 adults and children ≥4 years). Milk-alternative drinks were consumed by 4·6 % (n 185; n 88 consumed these drinks exclusively). Iodine intake was significantly lower in exclusive consumers of milk alternatives than cows’ milk consumers (94 v. 129 µg/d; P < 0·001). Exclusive consumers of milk alternatives also had a lower median UIC than cows’ milk consumers (79 v. 132 µg/l; P < 0·001) and were classified as iodine deficient by the WHO criterion (median UIC < 100 µg/l), whereas cows’ milk consumers were iodine sufficient. These data show that consumers of unfortified milk-alternative drinks are at risk of iodine deficiency. As a greater number of people consume milk-alternative drinks, it is important that these products are fortified appropriately to provide a similar iodine content to that of cows’ milk.

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Iodine deficiency in pregnant women in Sweden: a national cross-sectional study

European Journal of Nutrition ◽

10.1007/s00394-019-02102-5 ◽

2019 ◽

Vol 59 (6) ◽

pp. 2535-2545 ◽

Cited By ~ 4

Author(s):

Sofia Manousou ◽

Maria Andersson ◽

Robert Eggertsen ◽

Sandra Hunziker ◽

Lena Hulthén ◽

...

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Geometric Mean ◽

Iodized Salt ◽

National Study ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Cross Sectional ◽

Iodine Status ◽

Supplement Use

Abstract Purpose Voluntary salt iodization at 50 mg/kg salt ensures adequate iodine nutrition in Swedish school-aged children, but iodine status in pregnant women is uncertain. Methods We conducted a cross-sectional national study of 743 pregnant women, at median gestational age of 23 weeks (IQR 9, 38), recruited from maternal health care centers. We measured: urinary iodine concentration (UIC) and urinary creatinine concentration in spot urine samples; thyroglobulin (Tg), thyroid-stimulating hormone (TSH), and total thyroxine (tT4) on dried blood spots (DBS); and thyreoperoxidase antibodies in serum samples. Data on dietary supplement use were obtained, and women were classified as supplement users (consuming multivitamins containing ≥ 150 µg iodine/day) and non-supplement users (no supplements or < 150 µg iodine/day from supplements). Results Overall median UIC [bootstrapped 95% confidence interval (CI)] was 101 µg/L (95, 108; n = 737): 149 µg/L (132, 164) in supplement users (n = 253) and 85 µg/L (79, 92) in non-supplement users (n = 440) (p < 0.001). Overall geometric mean DBS-Tg (95% CI) was 22.1 μg/L (20.8, 23.5; n = 675) and the prevalence of elevated DBS-Tg was 19%. DBS-Tg was lower in supplement users (n = 229) than in non-supplement users (n = 405) (19.1 vs 24.4 μg/L, p < 0.001). DBS-TSH, DBS-tT4, and S-TPOab positivity did not differ between the two groups. Conclusions Pregnant women in Sweden have inadequate iodine nutrition. Women not taking iodine supplements containing ≥ 150 µg iodine/day are affected by mild iodine deficiency and are at higher risk for increased thyroid activity, while maintaining euthyroidism. Iodine intake should be improved in women both before and after conception by promotion of iodized salt instead of non-iodized salt. We urge regular monitoring of iodine status in the general Swedish population, as well as in risk groups.

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Development and validation of an iodine-specific FFQ to estimate iodine intake in Australian pregnant women

British Journal Of Nutrition ◽

10.1017/s0007114515000197 ◽

2015 ◽

Vol 113 (6) ◽

pp. 944-952 ◽

Cited By ~ 14

Author(s):

Dominique Condo ◽

Maria Makrides ◽

Sheila Skeaff ◽

Shao J. Zhou

Keyword(s):

Pregnant Women ◽

Urinary Iodine ◽

Optimal Growth ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Excretion ◽

Urinary Iodine Concentration ◽

Food Record ◽

Total Iodine ◽

Supplement Use

Adequate iodine is important during pregnancy to ensure optimal growth and development of the offspring. We validated an iodine-specific FFQ (I-FFQ) for use in Australian pregnant women. A forty-four-item I-FFQ was developed to assess iodine intake from food and was administered to 122 pregnant women at 28 weeks gestation. Iodine supplement use was captured separately at 28 weeks gestation. Correlation between iodine intake from food estimated using the I-FFQ and a 4 d weighed food record as well as correlation between total iodine intake and 24 h urinary iodine excretion (UIE), 24 h urinary iodine concentration (UIC), spot UIC and thyroid function were assessed at 28 weeks gestation. A moderate correlation between the two dietary methods was shown (r0·349,P< 0·001), and it was strengthened with the addition of iodine supplements (r0·876,P< 0·001). There was a fair agreement (k= 0·28,P< 0·001) between the two dietary measures in the classification of women as receiving adequate ( ≥ 160 μg/d) or inadequate ( < 160 μg/d) iodine intake from food, but the limits of agreement from the Bland–Altman plot were large. Total iodine intake was associated with 24 h UIE (β = 0·488,P< 0·001) but not with spot UIC. Iodine intake from food using the I-FFQ was assessed at study entry ( < 20 weeks gestation) in addition to 28 weeks gestation, and there was a strong correlation in iodine intake at the two time points (r0·622,P< 0·001), which indicated good reproducibility. In conclusion, the I-FFQ provides a valid tool for estimating iodine intake in pregnant women and can be used to screen women who are at risk of inadequate intake.

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Indicators of Iodine Status in Pregnancy and Postpartum in a Group of Pregnant Women from Perimarine Area of Romania

ARS Medica Tomitana ◽

10.2478/arsm-2020-0013 ◽

2020 ◽

Vol 26 (2) ◽

pp. 63-69

Author(s):

Scrinic Olesea ◽

Delia Corina Elena ◽

Toma Geanina Mirela ◽

Circo Eduard

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Iodized Salt ◽

Urinary Iodine Concentration ◽

Urinary Creatinine ◽

Iodine Status ◽

In Pregnancy

Abstract Objective: Assessment of iodine nutritional status in pregnant women in the perimarine area of Romania, a region without iodine deficiency. Adequate iodine intake is the main source for normal thyroid function, ensuring the need for maternal thyroid hormones during pregnancy, but also for the development and growth of children in the fetal and postpartum period. Material and method: Prospective study performed on 74 pregnant women in the first 2 trimesters of pregnancy, originating from the perimarin area. The following indicators of iodine status were analyzed: urinary iodine concentration (UIC), the ratio between urinary iodine concentration and urinary creatinine (UIC/UCr), the prevalence of maternal goiter and the value of neonatal TSH (thyroid stimulating hormone). Results: The mean gestational age was 11 weeks. The ways of iodine intake are: iodized salt - 59.4%, iodized salt and iodine supplements- 23%, only iodine supplements -10.8% and 6.8% consume only non-iodized salt. The median of UIC was 133.03 mcg/l considered insufficient iodine intake (normal in pregnancy UIC >150 mcg/l), but the adjustment of UIC to urinary creatinine reveals a median of 152.83 mcg/g, a value that reflects an adequate iodine intake. The prevalence of goiter was 25.6% characteristic for a moderate iodine deficiency. The prevalence of neonatal TSH >5 mIU/L was registered in 18.8% characteristic of mild iodine deficiency. Conclusions: Monitoring of the iodine nutritional status is recommended for the prevention of disorders due to iodine deficiency under the conditions of universal salt iodization. Perimarine areas considered sufficient in iodine may show variations in iodine status in subpopulations under certain physiological conditions, such as pregnancy. An indicator of iodine status of the population is UIC, but the UIC/UCr ratio may be a more optimal indicator for pregnant women, to avoid possible overestimated results of iodine deficiency in pregnancy.

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Iodine nutrition status in clinically euthyroid pregnant women attending in BSMMU

Bangabandhu Sheikh Mujib Medical University Journal ◽

10.3329/bsmmuj.v9i1.28942 ◽

2016 ◽

Vol 9 (1) ◽

pp. 38

Author(s):

Md. Anowar Hossain ◽

M. Abul Hasanat ◽

Murshed Ahamed Khan ◽

Jobaida Naznin ◽

Kazi Ashraful Alam ◽

...

Keyword(s):

Pregnant Women ◽

Urinary Iodine ◽

Iodine Content ◽

Iodine Concentration ◽

Nutrition Status ◽

Urinary Iodine Concentration ◽

Digestion Method ◽

Iodine Nutrition ◽

Cross Sectional ◽

Nutritional Problem

Background: Iodine deficiency disorders (IDD) are common nutritional problem globally. All groups of people are affected by it, but the pregnant women and their neonates are most vulnerable.Objectives: This study was carried out to see the iodine status of pregnant women using median urinary iodine concentration (MUI) as a measure of outcome. Methods: This cross sectional observational study assessed the MUI in casual urine samples from 225 pregnant women (75 pregnants from each trimester) and 75 non-pregnant healthy controls. The urinary iodine content was estimated in urine sample using the method of Dunn et al. with the modification of Sandell & Kolthoff (wet digestion method).Results: Median value of urinary iodine in pregnant women was 48.21Ug/L compared to 52.27

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The impact of iodised salt or iodine supplements on iodine status during pregnancy, lactation and infancy

Public Health Nutrition ◽

10.1017/s1368980007360965 ◽

2007 ◽

Vol 10 (12A) ◽

pp. 1584-1595 ◽

Cited By ~ 50

Author(s):

Michael B Zimmermann

Keyword(s):

Pregnant Women ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Life Stages ◽

Lactating Women ◽

Iodine Status ◽

Iodised Salt ◽

The Impact

AbstractObjectives:Monitoring of iodine status during pregnancy, lactation and infancy is difficult as there are no established reference criteria for urinary iodine concentration (UI) for these groups; so it is uncertain whether iodized salt programs meet the needs of these life stages.Design and Subjects:The method used in this paper was: 1) to estimate the median UI concentration that reflects adequate iodine intake during these life stages; and 2) to use these estimates in a review of the literature to assess whether salt iodisation can control iodine deficiency in pregnant and lactating women, and their infants.Results:For pregnancy, recommended mean daily iodine intakes of 220-250 μg were estimated to correspond to a median UI concentration of about 150 μg l− 1, and larger surveys from the iodine sufficient countries have reported a median UI in pregnant women ≥ 140 μg l− 1. Iodine supplementation in pregnant women who are mild-to-moderately iodine deficient is beneficial, but there is no clear affect on maternal or newborn thyroid hormone levels. In countries where the iodine intake is sufficient, most mothers have median breast milk iodine concentration (BMIC) greater than the concentration (100-120 μg l− 1) required to meet an infant's needs. The median UI concentration during infancy that indicates optimal iodine nutrition is estimated to be ≥ 100 μg l− 1. In iodine-sufficient countries, the median UI concentration in infants ranges from 90-170 μg l− 1, suggesting adequate iodine intake in infancy.Conclusions:These findings suggest pregnant and lactating women and their infants in countries with successful sustained iodised salt programs have adequate iodine status.

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Urine Iodine Level in Iodine-Supplemented Pregnant Women: Oral Tablet versus Iodized Oil

Journal of the Medical Association of Thailand ◽

10.35755/jmedassocthai.2021.02.12153 ◽

2021 ◽

Vol 104 (2) ◽

pp. 310-315

Keyword(s):

Single Dose ◽

Pregnant Women ◽

Urinary Iodine ◽

Iodine Concentration ◽

Public Hospitals ◽

Urinary Iodine Concentration ◽

Iodized Oil ◽

Oral Tablet ◽

Iodine Supplementation ◽

Daily Vitamin

Background: Although the policy of universal salt iodization and daily iodine-containing vitamin supplementations were implemented, the urinary iodine concentration (UIC) in pregnant women in the northeast of Thailand still showed mild iodine deficiency. Objective: To determine UIC in pregnant women receiving daily iodine-containing vitamin versus a single dose of two iodized oil capsules. Materials and Methods: The present study was conducted between March 2014 and October 2015, in 21 public hospitals in Khon Kaen Province. Healthy singleton pregnancy of a gestational age of less than 20 weeks that had not received iodine-containing vitamin were enrolled. The participants were asked to take either daily one tablet vitamin or a single dose of two iodized oil capsules. Random urine was collected before and after taking medication. Neonatal thyroid stimulating hormone (TSH) was retrieved from medical record. Results: Of the 2,079 participants, median UIC of pre- and post-daily vitamin supplementation in 1,061 pregnant women were 116.0 and 126.2 mcg/L. Median UIC of pre- and post-single dose iodized oil in 973 participants were 110.4 and 108.6 mcg/L. There was no statistically significant increase UIC post iodine supplementation in both groups (p=0.169). The median neonatal serum TSH were 4.34 and 3.79 mU/L in daily vitamin and single dose respectively, which is significantly lower in the iodized oil group (p=0.023). Conclusion: Post iodine supplementation either by daily vitamin or single dose did not significantly increase UIC. Keywords: Iodine supplementation, Iodized oil, Urinary iodine concentration

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Optimal Assessment and Quantification of Iodine Nutrition in Pregnancy and Lactation: Laboratory and Clinical Methods, Controversies and Future Directions

Nutrients ◽

10.3390/nu11102378 ◽

2019 ◽

Vol 11 (10) ◽

pp. 2378 ◽

Cited By ~ 4

Author(s):

Creswell J Eastman ◽

Gary Ma ◽

Mu Li

Keyword(s):

Brain Damage ◽

Iodine Deficiency ◽

Placental Transfer ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

School Age Children ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Psychomotor Tests

Iodine intake must be boosted during pregnancy to meet the demands for increased production and placental transfer of thyroid hormone essential for optimal foetal development. Failure to meet this challenge results in irreversible brain damage, manifested in severity from neurological cretinism to minor or subtle deficits of intelligence and behavioural disorders. Attention is now being focused on explaining observational studies of an association between insufficient iodine intake during pregnancy and mild degrees of intellectual impairment in the offspring and confirming a cause and effect relationship with impaired maternal thyroid function. The current qualitative categorisation of iodine deficiency into mild, moderate and severe by the measurement of the median urinary iodine concentration (MUIC) in a population of school-age children, as a proxy measure of dietary iodine intake, is inappropriate for defining the degree or severity of gestational iodine deficiency and needs to be replaced. This review examines progress in analytical techniques for the measurement of urinary iodine concentration and the application of this technology to epidemiological studies of iodine deficiency with a focus on gestational iodine deficiency. We recommend that more precise definitions and measurements of gestational iodine deficiency, beyond a spot UIC, need to be developed. We review the evidence for hypothyroxinaemia as the cause of intrauterine foetal brain damage in gestational iodine deficiency and discuss the many unanswered questions, from which we propose that further clinical studies need to be designed to address the pathogenesis of neurodevelopmental impairments in the foetus and infant. Agreement on the testing instruments and standardization of processes and procedures for Intelligence Quotient (IQ) and psychomotor tests needs to be reached by investigators, so that valid comparisons can be made among studies of gestational iodine deficiency and neurocognitive outcomes. Finally, the timing, safety and the efficacy of prophylactic iodine supplementation for pregnant and lactating women needs to be established and confirmation that excess intake of iodine during pregnancy is to be avoided.

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