Oral contraceptives and hormone replacement therapy are closely associated with stroke: AHA

Sweden: The use of oral contraceptives and hormone replacement therapy was linked to an increased risk of stroke, particularly during the first year of usage, probably due to acute alterations in hemostatic equilibrium, says an article published in Stroke.

Exogenous hormones are used by millions of women worldwide as hormone replacement or oral contraceptives or treatment. Strokes connected with the use of oral contraceptives were first recorded shortly after their introduction. Since then, several studies have evaluated the risk of stroke, with variable results. Several factors have led to the difficulty in verifying this risk correctly. One key concern is that oral contraceptive formulations vary greatly, and they have evolved dramatically over time. Still, the time-dependent and long-term effects of exogenous hormones on stroke risk are unknown.

Therese Johansson and colleagues evaluated the relationship between self-reported oral contraceptive and hormone replacement therapy usage and stroke risk in 257 194 women born between 1939 and 1970 from the UK Biobank. Any sort of ischemic stroke, stroke, intracerebral hemorrhage, and subarachnoid hemorrhage were all outcomes. In Cox regression models, exposures were evaluated as time-varying variables.

The key findings of this study were as follows:

1. An elevated occurrence rate of any stroke was detected during the first year of oral contraceptive usage, but the risks were determined to be equivalent over the subsequent years of use when compared to non-users.

2. Similarly, the first year of hormone replacement medication usage was related to an elevated risk of any stroke as well as cause-specific stroke, including ischemic stroke and subarachnoid hemorrhage, which persisted for any stroke over the remaining years of use and after termination.

In conclusion, This study sheds fresh light on the impact of hormone exposure on stroke risk, demonstrating not only an overall risk but also strong impacts at the start of treatment.

Reference:

Johansson, T., Fowler, P., Ek, W. E., Skalkidou, A., Karlsson, T., & Johansson, Å. (2022). Oral Contraceptives, Hormone Replacement Therapy, and Stroke Risk. In Stroke. Ovid Technologies (Wolters Kluwer Health). https://doi.org/10.1161/strokeaha.121.038659