Ruth Hart was putting on her make-up one morning in March 2021 before heading to work, when she noticed something odd.

When Ruth, a 57-year-old civil servant, closed her left eye to apply eyeshadow, she noticed that her right eye’s vision seemed unusually dim, as if she were wearing sunglasses.

‘I did it again to be sure and every time I closed my left eye, it was the same. But things looked normal when I looked out of both eyes.’

Worried by this, Ruth arranged to see her optician within a few days. Contrary to the comfort she had hoped for, she was advised to undergo further tests because of inflammation in her optic nerve that her optician had identified.

After a three-month wait for an MRI, Ruth was called at 7am the day after the scan and told to come back to hospital as soon as possible.

During her visit to the eye specialist, Ruth observed an MRI scan displayed on the computer screen, where she saw a large white spot, a few centimeters wide, on the left side of her brain. Ruth, who lives with her husband in Braintree, Essex, and is a grandmother of three, recalls this moment.

This finding was identified as a meningioma, a type of slow-growing brain tumor. While these tumors are rarely cancerous, they can become life-threatening if they grow large enough to pressure the brain.

Ruth’s tumour was wrapped around the optic nerve connected to her right eye.

The unusual symptom appeared only when she closed her left eye because her brain had adapted by relying more on her left eye to compensate, doctors explained.

Three months after the MRI, Ruth received an early morning call at 7 am, urging her to return to the hospital promptly. The urgency was due to the meningioma, which has the potential to expand to a size that could compress the brain.

Like most people who develop a meningioma, there was no apparent cause and Ruth was told it was sheer bad luck.

Or so it was thought. For as the Daily Mail reported last month, three research papers in little over a year tell a very different story. They concluded that women were between three and five times more likely to develop a meningioma if they had used a brand of contraceptive jab – called Depo-Provera – for more than a year.

About 10,000 prescriptions a month are issued for the drug, also known as medroxyprogesterone acetate, in England alone.

It’s a hormone injection given every three months and works by preventing eggs from being released by a woman’s ovaries.

First licensed for use on the NHS more than 40 years ago, alarm bells over its safety rang with the publication of a study in March 2024, which concluded that women on the jab for at least a year were up to five times more at risk of developing a meningioma in their lifetime, the BMJ reported.

Then, in July, scientists at the University of British Columbia in Canada, who compared meningioma rates in 72,181 women on the jab with more than 247,000 women taking oral contraception found the risks of meningioma, were more than trebled in long-term jab users.

The tumours are slow-growing – increasing in size by about 1mm to 2mm a year – and most are only diagnosed when they are about 3cm, so they can be present for decades before causing any problems. This means some affected women may not make the link to their contraceptive jab.

Since reports appeared in the Daily Mail about the possible connection, many readers with meningiomas have been getting in touch. Although none can be certain the injection caused their tumours, one wrote: ‘I was always told I would never know what caused my tumour – but it’s looking more and more likely that I have Pfizer [the drug company which makes Depo-Provera] to thank for it.’

Meningiomas can cause vision loss, personality changes, memory loss and even paralysis. And while 70 per cent of patients are alive after ten years, between 10 and 20 per cent die within five years

The most common type of brain tumour – affecting 2,000 to 3,000 people a year in the UK – meningiomas form in the meninges, the outer layers of tissue that cover the brain.

They can cause vision loss, personality changes, memory loss and even paralysis. And while 70 per cent of patients are alive after ten years, between 10 and 20 per cent die within five years.

Why the contraceptive jab may trigger their growth is unclear. One theory is that the synthetic hormone it contains – progestogen – binds to meningioma cells and helps them to grow.

Some research suggests that certain versions of the Pill with progestogen may raise the risk of meningioma, but only in a minority of women who take it for more than five years.

Last October, the UK drug safety watchdog – the Medicines and Healthcare products Regulatory Agency – called on Pfizer to include a warning about the heightened risk in patient information leaflets that come with Depo-Provera. Pfizer wrote to NHS doctors urging them to immediately stop women diagnosed with a meningioma from using Depo-Provera.

In the US, a class action lawsuit is under way against Pfizer and generic manufacturers of the jab, with more than 500 women alleging that the companies were aware of the link but failed to adequately warn users of the risks or promote safer alternatives.

In the UK, hundreds of women have sought legal advice over whether it is possible to sue Pfizer for not warning them of the risks. Chaya Hanoomanjee, a partner at London law firm Austen Hays, told Good Health: ‘We are carrying out an investigation into a possible UK case against Pfizer.’

Researchers stress that although the risk to contraceptive jab users is significantly higher than those who are not on the injections, their chances of developing a meningioma are still very small. The University of British Columbia team noted that, for every 1,111 women on the jab, just one will develop a tumour.

Why the contraceptive jab may trigger the growth of meningiomas is unclear. One theory is that the synthetic hormone it contains – progestogen – binds to meningioma cells and helps them to grow

That is little consolation for Ruth, or the dozens of other worried readers who have contacted the Daily Mail in recent weeks.

Ruth only discovered the link when she read about it in the newspaper. ‘My initial reaction was anger,’ she says.

Ruth was put on the jab in 2001, when she was in her early 30s, because she suffered heavy, painful periods. Her GP said it would put an end to this, which it did and she remained on the jab for more than 20 years. ‘The only side-effect I was ever warned about was osteoporosis,’ she says. The jab can reduce bone density, as it reduces oestrogen levels.

Her GP wanted Ruth to stop using the jab when she turned 50, as the osteoporosis risks are considered too great after that. But she persuaded the doctor to let her stay on it until she was 54.

After her meningioma was detected, she underwent a six-and-a-half hour operation during which 90 per cent of the tumour was removed. The rest is curled around her optic nerve, so is too risky to extract. She has annual MRIs to check it is not growing.

Joann Hibbitt, 64, a seamstress who lives in Preston, Lancashire, was diagnosed by chance with a meningioma which was 4.5cm diameter in 2022, when an MRI scan for an unrelated throat problem spotted the tumour in the left side of her brain.

She had been on Depo-Provera for several years in the 1990s but was unaware of the potential tumour risk until she read about it in the Daily Mail in July.

‘My consultant thinks I’ve probably had the tumour for many years,’ says Joann. ‘But it’s too big and too deep in my brain to take it out.’

Joann also has an annual MRI scan to see if it is growing. She says doctors have warned that, if it does, ‘I could lose all feeling and control in the whole right side of my body’.

A spokesperson for the Faculty of Sexual and Reproductive Healthcare – which represents experts in contraception – told Good Health that women worried about the risk of meningioma should talk to their GP about other options, ‘but it’s important to remember that the overall risk is very small’.

Ruth, who has lost about 50 per cent of the vision in her right eye, says that given the choice now, she would ‘put up with the period pain’, rather than use the Depo-Provera jab.

‘As it is, it feels like I have a ticking timebomb inside my head and I think Pfizer should be held accountable for it.’

Pfizer declined to comment.