Women taking modern versions of the combined pill to avoid pregnancy are up to 42 per cent less likely to get ovarian cancer.
A study has revealed the newer combined versions of oral contraceptives reduce the cancer risk more than older ones with higher levels of hormones.
The cancer-preventing effect increased with periods of longer use and continued for several years after users stopped taking the drug, researchers said.
Cancer rates were compared among women who take hormonal contraceptives now, those who have done in the past, and those who never had.
Women currently taking any kind of hormonal contraception have a 42 per cent lower cancer risk, the study said, but the effect of pills used in the past was weaker.
Modern versions of the combined contraceptive pill have a higher protective effect against ovarian cancer than older types of hormonal contraception, according to research by the University of Aberdeen and the University of Copenhagen
The preventative effect on ovarian cancer has been known in oral contraceptive pills with high levels of the sex hormones for some time – but it was not known whether the newer versions of the pill had the same benefit.
Levels of the hormones oestrogen and progestogen have been getting steadily lower in contraceptive pills since the 1960s and 1970s.
Newer versions of the pill contain other drugs such as desogestrel, gestodene and drospirenone alongside the hormones.
And these pills – commonly sold under brand names Microgynon, Rigevidon, Yasmin, Cerazette and Loestrin 20 – have a stronger cancer-preventing effect.
Researchers at the University of Aberdeen and the University of Copenhagen in Denmark analysed data for nearly 1.9 million Danish women aged 15-49 years between 1995 and 2014.
Women were categorised as never having used hormonal contraceptive drugs, current users, or former users who had stopped taking the drug for more than one year.
WHAT IS THE COMBINED PILL?
The combined oral contraceptive pill is usually just called ‘the pill’.
It contains the female sex hormones oestrogen and progesterone and works by preventing the ovaries from releasing eggs each month – meaning sperm cannot fertilise them.
The pill is usually taken every day for three weeks then stopped for a week to allow the woman’s period to happen because the womb lining still thickens even if an egg is not released.
The pill is over 99 per cent effective if used properly, meaning fewer than one in 100 women using it will get pregnant.
There is no evidence that the pill makes women gain weight, but it carries a very low risk of causing blood clots or cervical cancer.
The pill does not protect against sexually transmitted infections.
Some 86 per cent of women who the hormonal contraceptives used oral products.
Those who had used them at some point in the past had a 34 per cent lower risk of ovarian cancer.
The study authors said: ‘Based on our results, contemporary combined hormonal contraceptives are still associated with a reduced risk of ovarian cancer in women of reproductive age, with patterns similar to those seen with older combined oral contraceptives.’
The researchers took account of several factors, including age and the number of children each women had.
They found the number of cases of ovarian cancer were highest in women who had never used hormonal contraception and lowest among those who were on the pill.
The reduced risk for combined products was seen with nearly all types of ovarian cancer.
And there was little evidence of important differences between pills containing different types of progestogens.
Based on these figures, the researchers say that hormonal contraception prevented an estimated 21 per cent of ovarian cancers in this group of women.
The researchers pointed out that one weakness of the research is they did not study older women, among whom most cases of ovarian cancer occur.
The study was published in the British Medical Journal.