Birth Control Increases Stroke Risk

Results of recent studies suggest that oestrogen — present in oral contraceptive pills — may be the main driver of stroke risk among users

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For millions of women, combined hormonal contraceptives are a part of their daily life, providing a convenient and effective option for preventing pregnancy and managing their menstrual cycle. But new findings are sounding the alarm on a serious, and often overlooked, risk: stroke.

According to recent findings presented at the European Stroke Organisation Conference, combined oral hormonal contraceptives (which contain both oestrogen and progestogen) may significantly increase the chance of women experiencing a cryptogenic stroke. This is a sudden and serious type of stroke that occurs with no obvious cause.

Surprisingly, in younger adults — particularly women — cryptogenic strokes make up approximately 40 per cent of all strokes.

This suggests there may be sex-specific factors which contribute to this risk, such as hormonal contraception use. These recently-presented findings lend themselves to this theory.

At this year's conference, researchers presented findings from the Secreto study. This is an international investigation that has been conducted into the causes of unexplained strokes in young people aged 18 to 49. The study enrolled 608 patients with cryptogenic ischaemic stroke from 13 different European countries.

One of their most striking discoveries was that women who used combined oral contraceptives were three times more likely to experience a cryptogenic stroke compared to non-users. These results stood, even after researchers adjusted for other factors which may have contributed to stroke risk (such as obesity and history of migraines).

It's well-documented that hormonal contraceptives, which contain both oestrogen and progestin, come with a small, increased risk of experiencing serious health events, including stroke — particularly ischaemic stroke, which occurs when blood flow to part of the brain is blocked.