The use of certain contraceptives and hormone treatments for more than a year has been linked to an increased risk of developing a type of brain tumour called a meningioma.

This is the main finding of a French study that investigated a range of progesterone-like hormones that are used as contraception, menopausal hormone therapies, and to treat endometriosis.

One of these hormones, medroxyprogesterone acetate, is estimated to be used for birth control by 74 million women worldwide.

This hormone is marketed in Australia as Depo-Provera, an injectable contraception.

That medroxyprogesterone acetate is so widely used, globally, suggests the number of attributable intracranial meningiomas may be high.

Meningioma is the most common type of primary brain tumour, accounting for about 30 per cent of all brain tumours.

They are usually benign so they don’t tend to spread to distant parts of the body.

But because of its location, a meningioma can still cause neurological problems.

As these tumours grow, they can compress the brain and spinal cord, leading to serious symptoms.

Three high-dose progestogens (nomegestrol, chlormadinone and cyproterone acetate) are already known to increase the risk of meningioma.

The study

Funded by the French National Agency for Medicines and Health Products Safety, this study is reportedly the first to assess risk associated with widely used progestogens.

It was published by the British Medical Journal.

Progestogens are described as “similar to the natural hormone progesterone, which are widely used for gynaecological conditions such as endometriosis and polycystic ovary syndrome, and in menopausal hormone therapy and contraceptives”.

The study used data from the French national health data system (SNDS) for 18,061 women (average age 58) who underwent intracranial meningioma surgery from 2009 to 2018.

Each case was matched to five control women without intracranial meningioma (total 90,305) by year of birth and area of residence.

The progestogens examined were progesterone, hydroxyprogesterone, dydrogesterone, medrogestone, medroxyprogesterone acetate, promegestone, dienogest, and levonorgestrel intrauterine systems.

For each progestogen, use was defined as at least one prescription in the year before hospital admission or within three to five years for levonorgestrel intrauterine systems.

Use of at least one of the three high-dose progestogens known to increase the risk of meningioma in the three years before hospital admission was also recorded to minimise bias.

The results

After taking account of other potentially influential factors, prolonged use (a year or more) of:

• Medrogestone was associated with a 4.1-fold increased risk of intracranial meningioma requiring surgery
• Medroxyprogesterone acetate injection (used in Australia) was associated with a 5.6-fold increased risk
• Promegestone was linked to a 2.7-fold increased risk.

There appeared to be no such risk for less than one year of use of these progestogens.

Gino Pecoraro is associate professor of obstetrics and gynaecology at the University of Queensland. He is also a practising obstetrician and gynaecologist in private practice in Brisbane.

He said: “Of the hormones found to have an increased risk of meningioma, two are not available in Australia.

“The third, however, is available in Australia.”

He was referring to Depo Provera which is delivered via injection intramuscularly every three months. The active drug is medroxyprogesterone acetate 150mg.

The intrauterine levonorgestrel system (Mirena), increasingly used in Australia, didn’t show an excess risk of meningioma.

Dr Pecoraro said the study “should be reassuring to Australian women”.

Essentially because “the majority of contraceptives available are not associated with an increased risk of developing meningioma”.

He said the release of these findings “should also be a timely reminder to women to review their contraceptive needs periodically”.

This is to ensure they are still using the best product available for them.