Prolonged use of certain progestogen hormone drugs is associated with an increased risk of developing a type of brain tumor known as an intracranial meningioma, finds a study from France published by The BMJ today.

The researchers say this study is the first to assess the risk associated with progestogens used by millions of women worldwide, and further studies are urgently needed to gain a better understanding of this risk.

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