Women using levonorgestrel-releasing intrauterine devices (LG-IUDs) were found to be 22% less likely to have a stroke compared to those not using hormonal contraception, according to a recent study. The research, conducted in Denmark, also indicated no increased risk for intracerebral hemorrhage among LG-IUD users.
Study Overview
The study, led by Dr. Tom Skyhøj Olsen of Bispebjerg University Hospital in Copenhagen, analyzed data from 1.7 million women. Published online on May 16, 2024, in the journal Stroke, the research explored the relationship between LG-IUD usage and stroke risk, a topic that had not been extensively studied previously.
Key Findings
The findings suggested that LG-IUDs might have potential benefits beyond contraception, particularly in reducing the risk of ischemic stroke. In comparison to combined hormonal contraceptives, which are associated with an increased risk of ischemic stroke, progestin-only options like LG-IUDs appear to lower this risk. The study also affirmed previous research indicating that LG-IUDs might reduce the risk of thromboembolism.
Data and Methodology
Drawing from several national databases, including the Danish Stroke Registry, the historic cohort study included nonpregnant women aged 18-49 who lived in Denmark between 2004 and 2021. The average age of participants was 30 years, with a mean follow-up period of about seven years. Of the 1.7 million women, over 364,700 used LG-IUDs.
During the study period, 2,916 women experienced an ischemic stroke, while 367 had an intracerebral hemorrhage. Among LG-IUD users, the incidence of stroke was 19.2 per 100,000 person-years, compared to 25.2 per 100,000 person-years in women who did not use hormonal contraception. This translated to a 22% lower risk of ischemic stroke for LG-IUD users (IRR, 0.78; 95% CI, 0.70-0.88).
Age and Risk Factors
The study examined stroke incidence across different age groups: 18-29, 30-39, and 40-49 years. Results showed no significant variation in stroke risk between these age groups. However, the risk of intracerebral hemorrhage was notably higher in women aged 18-29 compared to those aged 40-49 (IRR, 4.49; 95% CI, 1.65-12.19). Researchers advised caution in interpreting these findings due to the low overall number of events, leading to wide confidence intervals.
Additionally, women who moved to Denmark from non-Western countries had a significantly lower stroke rate than native Danes. Country of origin did not impact intracerebral hemorrhage rates.
Study Limitations
The researchers acknowledged certain limitations, including indirect information about stroke risk factors such as diabetes, high blood pressure, and migraine. There was also no data on smoking, alcohol consumption, or body mass index.
Conclusion
While the study offers promising insights into the potential stroke-preventive properties of LG-IUDs, the researchers stressed the need for further investigation to confirm these findings. “Regarding a possible potential for stroke prevention, our study cannot stand alone and requires confirmation in further research,” the authors concluded.
The study received funding from the Aase og Ejnar Danielsens Fond and Familien Hede Nielsens Fond, with no reported conflicts of interest among the authors.
Implications for Women’s Health
This study contributes to the growing body of evidence supporting the safety and additional health benefits of progestin-only contraceptives like LG-IUDs. It underscores the importance of considering various contraceptive options and their broader health implications in clinical decision-making for women.
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