University of Oulu

Purdue-Smithe, A. C., Männistö, T., Reische, E., Kannan, K., Kim, U.-J., Suvanto, E., Surcel, H.-M., Gissler, M., & Mills, J. L. (2021). Iodine and thyroid status during pregnancy and risk of stillbirth: A population-based nested case–control study. Maternal & Child Nutrition, 18:e13252.

Iodine and thyroid status during pregnancy and risk of stillbirth : a population-based nested case–control study

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Author: Purdue-Smithe, Alexandra C.1; Männistö, Tuija2; Reische, Elijah1;
Organizations: 1Division of Intramural Population Health Research, National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA
2Northern Finland Laboratory Center NordLab, Oulu University Hospital, Oulu, Finland
3Department of Pediatrics and Department of Environmental Medicine, New York University School of Medicine, New York, New York, USA
4Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, Texas, USA
5Oulu University Hospital, Department of Children and Women and Oulu University Medical Faculty PEDEGO Research Unit, Medical Research Center, Oulu, Finland
6Biobank Borealis of Northern Finland, Oulu University Hospital, Oulu, Finland
7Faculty of Medicine, University of Oulu, Oulu, Finland
8Information Services Department, Finnish Institute of Health and Welfare, Helsinki, Finland
9Department of Neurobiology, Karolinska Institute, Stockholm, Sweden
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.1 MB)
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Language: English
Published: John Wiley & Sons, 2022
Publish Date: 2022-03-09


Prior research suggests that severe iodine deficiency in pregnancy may be associated with stillbirth. However, the relationship between mild to moderate iodine insufficiency, which is prevalent even in developed countries, and risk of stillbirth is unclear. We thus examined associations of iodine status and risk of stillbirth in a prospective population-based nested case–control study in Finland, a mild to moderately iodine insufficient population. Stillbirth cases (n = 199) and unaffected controls (n = 249) were randomly selected from among all singleton births in Finland from 2012 to 2013. Serum samples were collected between 10 and 14 weeks gestation and analysed for iodide, thyroglobulin (Tg) and thyroid-stimulating hormone (TSH). Odds ratios (ORs) and 95% confidence intervals (CIs) for stillbirth were estimated using logistic regression. After adjusting for maternal age, prepregnancy body mass index, socio-economic status and other factors, neither high nor low serum iodide was associated with risk of stillbirth (Q1 vs. Q2–Q3 OR = 0.92, 95% CI = 0.78–1.09; Q4 vs. Q2–Q3 OR = 0.78; 95% CI = 0.45–1.33). Tg and TSH were also not associated with risk of stillbirth in adjusted models. Maternal iodine status was not associated with stillbirth risk in this mildly to moderately iodine-deficient population. Tg and TSH, which reflect functional iodine status, were also not associated with stillbirth risk. The lack of associations observed between serum iodide, TSH and Tg and risk of stillbirth is reassuring, given that iodine deficiency in pregnancy is prevalent in developed countries.

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Series: Maternal & child nutrition
ISSN: 1740-8695
ISSN-E: 1740-8709
ISSN-L: 1740-8695
Volume: 18
Issue: 1
Article number: e13252
DOI: 10.1111/mcn.13252
Type of Publication: A1 Journal article – refereed
Field of Science: 3123 Gynaecology and paediatrics
Funding: This research was funded by the Office of Dietary Supplements of the National Institute of Health, USA (contract numbers HHSN275201100001 and HHSN27500009); the Finnish Medical Association of Clinical Chemistry and the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Some of the authors work directly for the funding agencies, and the authors were solely responsible for determining the design, conduct, analysis and reporting of the study.
Copyright information: © 2021 The Authors. Maternal & Child Nutrition published by John Wiley & Sons Ltd. This article has been contributed to by US Government employees and their work is in the public domain in the USA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.