This new analysis of 24 studies involving more than 50,000 women who took birth control pills showed a link between contraceptives and cervical cancer, but only later on in the women’s life. Women who took birth control pills at least five years doubled the risk of developing cervical cancer. The report was published today in the U.K. medical journal The Lancet.

Other studies have shown that pills, especially those made by Germany’s Bayer AG, lower the risk of ovaries and endometrial lining of the womb cancers.

Jane Green of Oxford University, who led the international group of researchers, said that "the extra risk of cervical cancer is more than outweighed by a reduction in risk'' of ovaries and endometrium tumors.

Researchers also found that 10 years after women stopped taking pills, the risk of cervical cancer dropped at the level of women who never took contraceptives in their lives.

The disease usually appears later in life, after 50, when women don’t need birth control pills anymore. The scientists discovered that, at age 50, one woman for every 1,000 women who took contraceptives in their 20s will have gotten cervical cancer. So, researchers reassure women that there is no real reason to avoid using oral contraception. But is the first time when a study shows how long the contraceptives’ effect persists after their use had been stopped.

Cancer expert Professor Ciaran Woodman, from the University of Birmingham, said: "This is an interesting and carefully conducted study which suggests an increased risk of cervical cancer associated with the use of the contraceptive pill. The take-home message should be that all women must come for screening when invited."