Hypothyroidism in Danish Pregnant Women Across Decades
Authors' conclusion
When evaluated in a large nationwide cohort across decades, the occurrence of hypothyroidism in Danish pregnant women increased. Regional differences were found and encourage further studies on the underlying mechanisms.
Study context
- Population
- Pregnant women in Denmark, 1997–2016, with a singleton, live-born pregnancy; hypothyroidism from redeemed LT4 prescriptions
- Participants
- 1,189,134 women
- Exposure
- East Denmark vs West Denmark, 1997–2016
- East Denmarkn = 549,410
- West Denmarkn = 639,724
- Outcome
- Incidence and prevalence of maternal hypothyroidism in pregnancy (redeemed LT4 prescriptions)
- Follow-up
- 1997-2016
Methodological detailsstratified by region (East vs West Denmark) as proxy of iodine intake
- Stratified by region (East vs West Denmark) as proxy of iodine intake
Main finding
As reported in the abstract
Incidence of maternal hypothyroidism in pregnancy · 1997 (3 years before iodine fortification) and 2016
| Group | Value | Incidence 2016 (per 1000 pregnancies; 95% CI 8.0-10.3) | Incidence 2016 (per 1000 pregnancies; 95% CI 4.3-6.0) |
|---|---|---|---|
| East Denmark | 0.55/1000 pregnancies (CI 0.30–0.93) | 9.1 | |
| West Denmark | 0.48/1000 pregnancies (CI 0.27–0.77) | 5.1 |
Value
East Denmark0.55/1000 pregnancies (CI 0.30–0.93)
West Denmark0.48/1000 pregnancies (CI 0.27–0.77)
Incidence 2016 (per 1000 pregnancies; 95% CI 8.0-10.3)
East Denmark9.1
West Denmark— not stated in the abstract
Incidence 2016 (per 1000 pregnancies; 95% CI 4.3-6.0)
East Denmark— not stated in the abstract
West Denmark5.1
Observational data: associations, not effects.
Further findings
| Outcome | East Denmark | West Denmark |
|---|---|---|
| Prevalence of hypothyroidism in pregnancy, 1997-1999 | 3.8/1000 pregnancies | 3.1/1000 pregnancies |
| Prevalence of hypothyroidism in pregnancy, 2013-2016 | 24.5/1000 pregnancies | 15.8/1000 pregnancies |
Original publication
Hypothyroidism in Danish Pregnant Women Across Decades. J Clin Endocrinol Metab. Published 21 May 2025. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →