University of Oulu

Turunen, S, Vääräsmäki, M, Lahesmaa-Korpinen, A-M, et al. Maternal hyperthyroidism and pregnancy outcomes: A population-based cohort study. Clin Endocrinol (Oxf). 2020; 93: 721– 728.

Maternal hyperthyroidism and pregnancy outcomes : a population-based cohort study

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Author: Turunen, Suvi1; Vääräsmäki, Marja1; Lahesmaa-Korpinen, Anna-Maria2;
Organizations: 1Department of Obstetrics and Gynecology, PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
2Finnish Institute for Health and Welfare, Information Services Department, Helsinki, Finland
3Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Stockholm, Sweden
4Northern Finland Laboratory Centre Nordlab, Oulu University Hospital, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.2 MB)
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Language: English
Published: John Wiley & Sons, 2020
Publish Date: 2021-11-02


Objective: Maternal hyperthyroidism and antithyroid medications have been associated with adverse pregnancy and perinatal outcomes. This nationwide register-based study investigated the association of maternal hyperthyroidism and antithyroid drug (ATD) use with pregnancy outcomes and included all singleton births in Finland between 2004 and 2013 (N = 571 785).

Design, patients and measurements: Hyperthyroid mothers were identified in the Medical Birth Register, and data on ATD use before and/or during pregnancy were collected from the Prescription Register. The odds ratios, with 95% confidence intervals, for adverse outcomes among hyperthyroid mothers and mothers without thyroid disease were compared using logistic regression.

Results: In total, 2144 (0.37%) of all the women had diagnoses of hyperthyroidism, and 580 (27%) of these women had used ATDs before and/or during pregnancy. Compared to the mothers without thyroid disease, maternal hyperthyroidism was associated with older age, multiparity, smoking, previous miscarriages, and overweight or obesity. The mothers diagnosed with hyperthyroidism also had increased odds of gestational hypertensive disorders, caesarean sections, placental abruptions, preterm births, small-for-gestational-age newborns and neonatal intensive care unit treatment. The odds of pregnancy and/or perinatal complications were higher among those who had used ATDs (indicative of active disease), but those who had not received ATD treatment also had increased odds of such complications compared to the mothers without thyroid disease.

Conclusions: Women with active hyperthyroidism and those with histories of hyperthyroidism should be considered at risk of developing pregnancy and perinatal complications and should therefore be monitored during pregnancy.

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Series: Clinical endocrinology
ISSN: 0300-0664
ISSN-E: 1365-2265
ISSN-L: 0300-0664
Volume: 93
Issue: 6
Pages: 721 - 728
DOI: 10.1111/cen.14282
Type of Publication: A1 Journal article – refereed
Field of Science: 3123 Gynaecology and paediatrics
Funding: This work was supported in part by the Northern Ostrobothnia Hospital District (Suvi Turunen), the Drugs and Pregnancy project of the THL, the Finnish Medicines Agency (FIMEA), and Kela (Mika Gissler, Maarit K Leinonen and, Anna-Maria Lahesmaa-Korpinen).
Dataset Reference: Supporting information:
Copyright information: © 2020 John Wiley & Sons Ltd. This is the peer reviewed version of the following article: Turunen, S, Vääräsmäki, M, Lahesmaa-Korpinen, A-M, et al. Maternal hyperthyroidism and pregnancy outcomes: A population-based cohort study. Clin Endocrinol (Oxf). 2020; 93: 721– 728, which has been published in final form at]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.