Women who take the Pill or HRT could have greater protection against brain aneurysms, according to a new study.

Researchers believe pills containing oestrogen may help lower the risk of the potentially fatal condition.

An aneurysm occurs when a blood vessel becomes weak in places and a bulge is created as blood passes through it.

If an aneurysm balloons and grows too big, there is a danger it will rupture, causing internal bleeding and organ damage.

Between one and six per cent of all people in England are thought to have a brain aneurysm and ruptured brain aneurysms cause around 1,400 deaths every year.

In people who suffer a ruptured aneurysm, around 65 per cent to 85 per cent will die.

For the latest study, experts asked 60 women with intact brain aneurysms about their use of the oral contraceptive pill and hormone replacement therapy (HRT).

The results were compared with more than 4,600 women from the general population.

The women with brain aneurysms, who ranged in age from 31 to 80, were found to be significantly less likely to have taken oral contraceptives or HRT during their lives.

They also had an earlier average age of menopause.

Experts already know that brain aneurysms are more common in women and that oestrogen helps maintain the structure of blood vessel walls.

The hormone promotes the division of cells, which is vital for repairing damaged vessels.

But oestrogen levels drop significantly when women reach the menopause.

Women are more likely to develop a brain aneurysm after 40 and the bulge is most likely to rupture between the ages of 50 and 59.

Previous studies have shown that taking the Pill helps protect against haemorrhagic stroke in later life, while women who start their periods early and/or do not have children are at greater risk.

The researchers, from universities in Illinois and Virginia in the US, said there are limited options for caring for people with aneurysms.

Those that do exist focus on stents, clips or balloons to prevent the condition getting worse.

“Such an approach leads to prognostic uncertainty and a future filled with anxiety provoking surveillance imaging for the patient,” they said.

“The results of this study may not only provide additional insight into cerebral aneurysm pathophysiology but, more importantly, may lead to more pathology-based therapies to patients either harbouring an unruptured cerebral aneurysm or at risk of developing one.”