But a Cancer Research UK study released this morning shows that risk starts falling soon after the pill is stopped and has disappeared within 10 years.

And the known increased risk of breast and cervical cancer is outweighed by reduced risks for ovarian and womb cancer, one of the charity's lead researchers said.

The combined pill, usually just called the pill, is one of the most popular forms of contraception with thousands of women across Ulster using it.

Today's study, published in the Lancet, confirms previous research linking the pill with an increased risk of cervical cancer.

It reveals for the first time, however, that this risk falls after pill use stops.

Around 88 women are diagnosed with cervical cancer in Northern Ireland each year. The disease kills about 19 women here every year.

Dr Jane Green, lead researcher based at Cancer Research UK's epidemiology unit at the University of Oxford, said the study confirmed that women who are taking the pill have a small increased risk of cervical cancer.

"The pill remains one of the most effective forms of contraception, and in the long term the small increases in risk for cervical and breast cancers are outweighed by reduced risks for ovarian and womb cancer," she said.

Dr Lesley Walker, Cancer Research UK's director of information, said: " The link between the contraceptive pill and cervical cancer has been known for some time. This study helps us to quantify the risk and to understand how long the risk persists.

"Cervical cancer can be largely prevented by going for regular smear tests so it's vital that all women go for screening when they are invited.

"It is important for women to weigh up the risks and benefits of taking the pill for themselves and to speak to their doctor if they are concerned. In future we hope that many more cases of cervical cancer will be prevented as a result of the recently-announced HPV vaccination programme."

Researchers looked at 24 separate studies of more than 52,000 women from 26 countries. Previous research has also shown an increase in breast cancer risk but a decrease in ovarian and womb cancer in women on the pill.

Cases of cervical cancer peak in women in their 30s and there is only a small overall effect on the lifetime risk of developing cervical cancer from use of the pill in young women.

Cervical cancer risk for women up to the age of 50 in developed countries who have never used the pill is 3.8 in 1,000. This increases to 4.0 per 1,000 in women who use the pill for five years, and to 4.5 per 1,000 for those who take the pill for 10 years.