Women who take the contraceptive pill are at increased risk of cervical cancer and should have regular screenings for the disease, doctors warn.

But the increased risk does not last and returns to normal 10 years after use of the Pill stops. The extra risk is also more than outweighed by the protective effect of the Pill against ovarian and endometrial (womb) cancer, so is not a reason to avoid taking it, they say.

A review of 24 studies of Pill use worldwide, including 16,000 women with cervical cancer and 35,000 without, found that, among users of the Pill, women who had taken it for five years had twice the risk of cervical cancer compared with those who had never taken it.

That confirms previous research which showed that the risk increases the longer the Pill is taken. For the first time, the research shows how long the effect persists after use of oral contraceptives stops.

The study, which was published in the medical journal The Lancet, estimated that 10 years' use of oral contraceptives from about the age of 20 to 30 increased the incidence of cervical cancer by the age of 50 from 3.8 to 4.5 per 1,000 women living in developed countries. In less developed countries, cervical cancer incidence rose from 7.3 to 8.3 per 1,000 women.