A comprehensive study from Uppsala University, involving more than 250,000 women, shows that oral contraceptive use protects against ovarian and endometrial cancer.
The protective effect remains for several decades after discontinuing the use.
The study is published in the journal Cancer Research.
Ovarian and endometrial cancer is among the most common gynaecological cancers, with a lifetime risk of just over 2 per cent.
Endometrial cancer is slightly more common but as it has clearer symptoms and is therefore often detected at an early stage, the mortality rate is low.
However, ovarian cancer is among the deadliest cancers, since it is often not detected until it has already spread to other parts of the body.The first oral contraceptive pill was approved already in the 1960s, and 80 per cent of all women in Western Europe have used oral contraceptives at some point in their life.