Birth control jab linked to ‘increased risk of brain tumours’

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

A study published in the British Medical Journal ( BMJ) found that people using injectable med roxy-progesterone 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.

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 study found that prolonged use of med roxy progesterone acetate was “associated with an excess risk of intracranial meningioma”.

Researchers, including from the French National Agency for Medicines and Health Products Safety, said: “In countries for which the use of med roxy progesterone acetate for birth control is frequent – 74 million users worldwide – the number of attributable meningiomas may be potentially high.”

The 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.

Results showed prolonged use of med roxy progesterone acetate injection was associated with a 5.6fold 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 all prescriptions but there were risks around med roxy progesterone 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 formed roxy progesterone acetate is causal.”

He said it was important to note that progestogens are an important component of many types of birth control pill (oral contraceptives) and hormone replacement therapy, but there are many different types of progestogens in common use that have no association with meningioma.

“This means that women taking the commonly used birth control pills or hormone replacement therapy are not at increased risk of meningioma.

“It is important that women do not stop using their birth control pills without consulting their doctor.

“The notable exception is med roxy-progesterone acetate( also known as Depo-Provera) which is sometimes used as an injectable form of contraception.”