Iodine supplementation during pregnancy and its effects on children's cognitive development

The Importance of Iodine During Pregnancy for Future Brain Function : a Randomized Placebo-controlled Trial. Swedish Iodine in Pregnancy and Development in Children (SWIDDICH) Study

Not applicable Interventional Göteborg University · NCT02378246

This study tests if giving pregnant women with low iodine a daily supplement can help their children think and learn better as they grow up.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment1275 (estimated)
Ages18 Years to 40 Years
SexFemale
SponsorGöteborg University Academic / other
Locations4 sites (Umea, Västerbotten and 3 other locations)
Trial IDNCT02378246 on ClinicalTrials.gov

What this trial studies

This study investigates whether administering a daily tablet containing 150 μg of iodine, along with vitamins and minerals, to pregnant women with mild iodine deficiency can improve cognitive development in their children. It is a randomized, placebo-controlled trial conducted in Sweden, with follow-up assessments of children's cognitive development at various ages. The study also examines the interaction between iodine, selenium, and iron, and measures various thyroid-related biomarkers in both mothers and newborns.

Who should consider this trial

Good fit: Ideal candidates for this study are pregnant women under 13 weeks of gestation, aged 18-40, who intend to have a full-term pregnancy and can commit to the study protocol.

Not a fit: Patients with known thyroid disease or those with risk factors for thyroid disease may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide evidence for the necessity of iodine supplementation during pregnancy to enhance cognitive outcomes in children.

How similar studies have performed: Previous studies have shown the importance of iodine in cognitive development, but this specific approach of supplementation in a mildly iodine-deficient population is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
PREGNANT WOMEN

Inclusion criteria

* Pregnant, week \<13
* Age 18-40 years
* Intent of a full term pregnancy
* Agreement of taking no iodide containing supplements during the study except for study supplement

Exclusion Criteria

* Known current thyroid disease
* Risk factors for thyroid disease (history or heredity for thyroid, other autoimmune disease or symptoms of hypo-/hyperthyroidism) where the TSH is abnormal
* Possibility to not attend to the protocol according to the investigator's opinion
* Less than 6 months from previous pregnancy or lactating period
* Vegan

CONTROL WOMEN

Inclusion criteria

* Age 18-40 years
* Agreeing not to take iodide containing supplements 1 week prior to the collecting of the samples.

Exclusion criteria

* Current thyroid disease
* Risk factors for thyroid disease (history or heredity for thyroid or other autoimmune disease or symptoms of hypo-/hyperthyroidism) where the TSH is abnormal
* Possibility to not attend to the protocol according to the investigator's opinion
* Currently pregnant or lactating
* Less than 6 months from previous pregnancy or lactating period
* Vegans

Where this trial is running

Umea, Västerbotten and 3 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Thyroid GlandNodePregnancyCognitive Developmental DelayIodineDouble-Blind MethodRandomized Controlled TriaCognitive Development
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.