Potential Preventive Effect of Selenium on Iodine-induced Thyroid Autoimmunity During Pregnancy
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ClinicalTrials.gov Identifier: NCT03377218 |
Recruitment Status : Unknown
Verified April 2018 by Ilze Konrade, Riga Stradins University.
Recruitment status was: Recruiting
First Posted : December 19, 2017
Last Update Posted : April 19, 2018
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In 1994, the WHO and UNICEF Joint Committee on Health Policy recommended Universal Salt Iodization as a safe, cost-effective and sustainable strategy to ensure sufficient intake of iodine by all individuals. However, it is still absent in Latvia.
A recent countrywide study in 2013 shows iodine deficiency among pregnant women in Latvia: 81 % of pregnant women had UIC levels below the WHO recommended range of 150-250 mcg/g Cr.
Because mild to moderate iodine deficiency during pregnancy can adversely affect fetal brain development, WHO-UNICEF and ICCIDD advise an increase in the recommended daily dosage of iodine to 250 mcg/day for pregnant women and breastfeeding women and 150 mcg/day for women in the preconception period.
Data from a survey of the Latvian population indicate that approximately 100 mcg of iodine per day is consumed through foods and iodized salt. To meet the increased iodine requirement in pregnancy, pregnant women should take a supplement containing 150 mcg of iodine daily from the earliest time possible.
A sudden increase in iodine intake in an iodine-deficient population may increase thyroid autoimmunity. It is evident that thyroid disease has multiple adverse effects during pregnancy and in the developing fetus especially in women with elevated serum anti-thyroid antibody titers.
Studies have considered supplementing with selenium to reduce the risk of auto-immune thyroiditis/post-partum autoimmune thyroid disease. Of the 11 trials of selenium supplementation in patients with autoimmune thyroiditis, 7 have shown benefit with treatment for 6 months or longer.
Aim of study is to approve that 150 mcg of iodine daily improves iodine status in pregnant women and iodine 150 mcg in combination with selenium 100 mcg daily reduce risk of thyroid autoimmunity.
Hypothesis of study is that 150 mcg iodine daily during pregnancy improves iodine status. Iodine in combination with selenium is less associated with thyroid autoimmunity.
Study design: Pregnant women are randomized for either 150 mcg iodine intake daily or 150 mcg iodine combined with 100 mcg selenium daily. Interventional group is compared with controls without particular iodine supplementation.
Participants are asked to complete a questionnaire on dietary habits concerning iodine. Thyroid function (thyroid-stimulating hormone, free thyroxine) and thyroperoxidase antibodies (TPO-Ab) and urinary iodine are measured during first, second and third trimester of pregnancy and week 8 after delivery in both, intervention and control group.
Condition or disease | Intervention/treatment | Phase |
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Pregnancy Thyroid Autoimmune Disease Iodine Deficiency Selenium Deficiency | Dietary Supplement: Iodine Dietary Supplement: Iodine + Selenium | Not Applicable |

Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 300 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Prevention |
Official Title: | Safety and Efficacy of Iodine Supplementation During Pregnancy With and Without Selenium Co-administration: Randomized Controlled Trial |
Actual Study Start Date : | January 5, 2018 |
Estimated Primary Completion Date : | December 2018 |
Estimated Study Completion Date : | January 2019 |
Arm | Intervention/treatment |
---|---|
No Intervention: Control
Without additional iodine supplementation.
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Experimental: Iodine
Receiving iodine.
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Dietary Supplement: Iodine
Receiving 150 μg iodine (as potassium iodide) daily |
Experimental: Iodine + Selenium
Receiving iodine and selenium.
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Dietary Supplement: Iodine + Selenium
Receiving a combination of 150 μg iodine (as potassium iodide) and 100 μg selenium daily |
- UIC [ Time Frame: At baseline - 9/10 weeks of gestation, second sample - 24 weeks of gestation (14 weeks from baseline), third sample - 34 weeks of gestation (24 weeks from the baseline) and fourth sample - 8 weeks postpartum- (38 weeks after the baseline sample) ]Urinary iodine concentration
- Change in anti-TPO Ab [ Time Frame: At baseline - 9/10 weeks of gestation, second sample - 24 weeks of gestation (14 weeks from baseline), third sample - 34 weeks of gestation (24 weeks from the baseline) and fourth sample - 8 weeks postpartum- (38 weeks after the baseline sample) ]Change in anti-thyroperoxidase antibodies
- TSH [ Time Frame: At baseline - 9/10 weeks of gestation, second sample - 24 weeks of gestation (14 weeks from baseline), third sample - 34 weeks of gestation (24 weeks from the baseline) and fourth sample - 8 weeks postpartum- (38 weeks after the baseline sample) ]Thyroid stimulating hormone
- fT4 [ Time Frame: At baseline - 9/10 weeks of gestation, second sample - 24 weeks of gestation (14 weeks from baseline), third sample - 34 weeks of gestation (24 weeks from the baseline) and fourth sample - 8 weeks postpartum- (38 weeks after the baseline sample) ]Free thyroxine

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- healthy women before 10 weeks of gestation
- signed informed consent form
Exclusion Criteria:
- pre-existing thyroid disease
- pregnancy after assisted reproductive technologies
- known hypersensitivity reaction to iodine or selenium, or other components of dietary supplement used in the study

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03377218
Contact: Ilze Konrade, professor | 29140141 ext +371 | drkonrade@inbox.lv | |
Contact: Vija Veisa, doctor | 26442100 ext +371 | vijaveisa@inbox.lv |
Latvia | |
Riga Maternity hospital | Recruiting |
Riga, Latvia | |
Contact: Dace Rezeberga, profesor +37167011211 dace.rezeberga@inbox.lv |
Principal Investigator: | Ilze Konrade, professor | Riga Stradins University |
Responsible Party: | Ilze Konrade, associate professor, Riga Stradins University |
ClinicalTrials.gov Identifier: | NCT03377218 |
Other Study ID Numbers: |
RigaStradinsU_Iodine3 |
First Posted: | December 19, 2017 Key Record Dates |
Last Update Posted: | April 19, 2018 |
Last Verified: | April 2018 |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Product Manufactured in and Exported from the U.S.: | No |
Thyroid Diseases Autoimmune Diseases Endocrine System Diseases Immune System Diseases Iodine Selenium Cadexomer iodine Anti-Infective Agents, Local Anti-Infective Agents |
Trace Elements Micronutrients Nutrients Growth Substances Physiological Effects of Drugs Antioxidants Molecular Mechanisms of Pharmacological Action Protective Agents |