Injectable contraception linked to increased risk of brain tumour

An injectable contraception used by women in some countries has been linked to an increased risk of a type of brain tumour.

The study, published in the British Medical Journal (BMJ), found people using injectable medroxyprogesterone acetate for more than a year appear to have a higher risk of meningioma – a tumour of the membranes covering the brain and spinal cord.

It is usually benign but can cause serious problems in some patients due to its location in and around the brain and spinal cord.

Symptoms of meningioma include change in vision, hearing loss or ringing in the ears, loss of smell, headaches, memory loss, seizures and weakness in arms or legs.

The new study linked some types of progestogen (similar to the hormone progesterone) to an increased risk of meningioma, though several types are not used in the UK.

However, it found that prolonged use of medroxyprogesterone acetate was “associated with an excess risk of intracranial meningioma”.

The French researchers, including from the French National Agency for Medicines and Health Products Safety, said: “In countries for which the use of medroxyprogesterone acetate for birth control is frequent (74 million users worldwide), the number of attributable meningiomas may be potentially high.”

In England, prescription data suggests there are around 10,000 prescriptions for medroxyprogesterone acetate every month.

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

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

The results showed that prolonged use of medroxyprogesterone acetate injection was associated with a 5.6-fold increased risk of meningioma.

Paul Pharoah, professor of cancer epidemiology at Cedars-Sinai Medical Centre in the US, said many of the findings in the study did not relate to UK prescriptions but there were risks around medroxyprogesterone acetate.

He added: "The authors note that causality cannot be determined in an observational study such as this but, given what we know about the risk factors for meningioma, it seems quite likely that the association reported for medroxyprogesterone acetate is causal."