Long-term use of contraceptives taken by millions of women linked to brain tumours, study
Contraceptives used by millions of women may significantly increase the risk of developing a common type of brain tumour, a major study suggests.
Danish researchers analysed the health records of three million women over 25 years and found that pills, injections and coils containing the hormone progestogen were associated with a significantly increased risk of meningioma.
This is usually non-cancerous tumour that develops in the tissues surrounding the brain and spinal cord.
Meningiomas are the most common type of brain tumour, accounting for more than a quarter of cases diagnosed in Britain and around 3,000 new cases each year.
While most are benign, they can cause headaches, seizures and vision problems as they grow and press on nearby tissue, sometimes requiring surgery or radiotherapy.
The strongest association was seen with one commonly used contraceptive injection, which was linked to a 355 per cent increase in the risk of developing a meningioma.
Previous studies have also suggested a link between progestogen-based medications and the tumours, which are known to occur more frequently in women than men.
Experts said the findings should help inform discussions between doctors and patients about the benefits and risks of different contraceptive options.
Some contraceptive pills, jabs and coils may put women at a greater risk of developing brain tumours, a major study has found
The study, published in JAMA Network Open, analysed health records from three million women aged 15 to 59 over a 25-year period.
Researchers compared 1,473 women diagnosed with meningioma with 14,717 women who did not have the tumour and found the strongest association among users of the contraceptive injection medroxyprogesterone.
Women using the drug, which is sold in Britain as Depo-Provera, had 355 per cent higher odds of developing a meningioma than those who did not take it.
The risk was highest among older women.
Among those aged 55 to 59, researchers estimated there was one additional case of meningioma for every 5,372 women using the injection for a year.
By comparison, among women aged 15 to 19, there was one extra case for every 449,000 users.
The researchers also found increased odds of meningioma among users of several combined contraceptive pills containing both oestrogen and progestogen.
The highest increase was linked to desogestrel, which was associated with a 66 per cent rise in odds, followed by cyproterone (61 per cent), drospirenone (58 per cent), gestodene (44 per cent), levonorgestrel (40 per cent), norethisterone (38 per cent) and norgestimate (4 per cent).
The NHS says natural family planning can be up to 99 per cent effective when done correctly and around 75 per cent if not used according to instructions. By comparison, the Pill, implant, IUS and IUD are 99 per cent effective with perfect use, while condoms are 98 per cent
Levonorgestrel and norethisterone are among the progestogens that have been used in contraceptives for decades and are found in well–known brands like Microgynon, Rigevidon and Brevinor.
For progestogen–only pills, known as mini pills, desogestrel was linked with a 73 per cent increase in the odds of developing meningioma. Norethisterone, however, showed no clear risk increase.
Desogestrel is one of the most commonly prescribed mini pills in Britain and is sold under brand names including Cerazette and Cerelle.
Women using coils containing high–dose levonorgestrel also had a 58 per cent increase in the odds of developing meningioma, while no clear increase in risk was found for low–dose levonorgestrel.
The authors, from the Danish Medicines Agency in Copenhagen, wrote: ‘These findings suggest that the risk of meningioma may extend beyond high–dose progestogens and medroxyprogesterone injections to include some contraceptive progestogens, including high–dose intrauterine devices with levonorgestrel.’
Importantly, the researchers found the risk generally disappeared within five years of stopping the contraceptive.
The team was unable to draw conclusions about several other progestogen–containing contraceptives because too few women had used them or too few cases of meningioma occurred.
These included etynodiol, lynestrenol, nomegestrol, dienogest, norelgestromin, drospirenone used as a progestogen–only pill, levonorgestrel used as a progestogen–only pill, and etonogestrel used in implants and vaginal rings.
The study also found no clear increase in risk for the combined pill norgestimate, the progestogen–only pill norethisterone, or the low–dose levonorgestrel coil.
Experts not involved in the research welcomed the study but stressed that the overall risk to women remained small.
Paul Pharoah, professor of cancer epidemiology at Cedars–Sinai Health Sciences University, said: ‘Importantly [the researchers] found that this risk only persisted while the women were using the hormonal contraceptive and declined once they stopped.
‘This is an observational study and determining that the observed associations are causal is difficult as it is hard to exclude all possible confounders. However, given all the available evidence it seems likely that the association is causal.’
Channa Jayasena, professor of reproductive endocrinology at Imperial College London, said: ‘All medications have risk, and contraceptive medications are no different. As the paper correctly states, the overall chance of these drugs giving you a meningioma is tiny.’
Gino Pecoraro, associate professor of obstetrics and gynaecology at the University of Queensland, added: ‘Prescribers should certainly be aware of the association between progestogen exposure and meningioma and also of non–progestogen–containing contraceptive options, including barrier methods and copper–containing IUDs should this association be of concern to the woman.
‘This is further evidence of the importance of appropriate contraceptive consultations addressing risks and benefits of various means of contraception, taking place between prescribers and women, prior to writing a script or making a recommendation.’