During pregnancy

How is the study conducted during pregnancy?

Pregnant women participating in the study are divided into 2 groups. One group takes a daily multivitamin tablet containing 150 micrograms of iodine, which is the same amount as several multivitamins available on the market. The second group receives a tablet without iodine (a placebo) which is common during pregnancy today in Sweden. The study participants are not going to know in advance which group they end up in. They will continue to take the tablets, up until delivery.

During the study period, blood samples will be collected for analysis of thyroid hormones, antibodies, and a marker for thyroid enlargement. Urine samples will be collected for analysis of iodine. You will also fill in a short questionnaire. The samples will be collected on 3 occasions: around pregnancy weeks 10, 25, and 36 where blood and urine samples are taken. We also have a Light version of the study where only urine samples are taken. Gothenburg and Umeå follow the Light version. Study supervisors also have access to the pregnancy record, delivery record, and information from PKU-lab, where the routinely taken neonatal screening tests of all newborns in Sweden are sent.

If possible, the tests and examinations during the pregnancy part of the study take place in connection with another routine testing at the Maternal Health Care Centre. In Gothenburg, study visits take place during pregnancy at Sahlgrenska University Hospital. On these occassions, it will only be necessary to draw blood an additional once or twice more. You will also answer a simple questionnaire regarding smoking and vitamin supplements.

Are there any risks?

Participating in the study provides no risks. Blood tests can cause discomfort.

Are there any benefits?

The child will be offered testing, developmental assessment by a psychologist, and assessment of motor development by a physiotherapist. In the case of deviating examination findings, the parent will be contacted, and a doctor will decide whether further investigation or other action needs to be undertaken.


Participation is voluntary and you can cancel your study participation at any time without needing to give any explanation. If you cancel your participation, this will not in any way affect you or your child's future health care in the health care system. You can also choose to refrain from parts of the survey. The contribution of each study participant is valuable.

Sample handling

Samples will be stored frozen in Biobank West (Reg. No. 890). The samples are stored in a coded form and the code key is stored so that unauthorized persons do not have access to it. The samples may only be used for the purposes approved by the Ethics Review Board. To be able to track samples in case of a changed consent, certain information about saved samples (biobank data) may be stored in the Swedish Biobank’s register.

Handling of personal data and confidentiality

All answers and results in the study, along with personal data, will be processed so that unauthorized persons cannot access them. Collected personal data will be retained for as long as they are needed to achieve the goal of the research project plus at least 15 years and will then be destroyed. Samples and coded data may be sent to collaborating researchers within and outside of the EU/EEA in collaborative projects.

The board of Sahlgrenska University Hospital is responsible for the processing of personal data. According to the GDPR, you have the right to apply for information about which personal data is processed. The Data Protection Officer is the person responsible for ensuring that your personal data is processed in a legal and correct manner. If necessary, the data protection officer can help you to get information about what has been registered and have any corrections made. The Data Protection Officer can be reached at Sahlgrenska University Hospital, Data Protection Officer, 413 45 Gothenburg, phone: 031-343 27 15.

Research ethics review

The Regional Ethics Review Board in Gothenburg has reviewed and approved this project. Saved samples and examination results may be used for other health-related research and in such a case, a new application to the Ethics Review Board will be sent for approval. The Regional Ethics Review Board assesses whether you need to be contacted again, to submit a new consent in such research projects. As previously described, all participation is voluntary.

Information about results

The results from the analyses will not be distributed consecutively, but they will be published in scientific journals in such a way that no individual can be identified. You will be informed about the results of the study at a group level.

Insurance and compensation

The pregnant woman and child are insured via the patient injury insurance in the same way as within general healthcare. The study does not entail any extra costs for you. Travel allowance may be relevant when visiting the research clinic.

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To read more about how the child follow-up is done, click here.