Combined hormonal contraceptives are associated with a significant reduction in ovarian cancer risk in women of reproductive age, according to a new study.
Researchers from the universities of Aberdeen and Copenhagen compared women who had never used hormonal contraceptives, with those had, and found that use of hormonal contraception prevented 21% of ovarian cancers.
They said that the protective effect of the contraceptives increased with longer duration of use, but did not extend to progestogen-only products.
The study, published in the BMJ, analysed national prescribing and cancer register data for nearly 1.9m Danish women aged 15 to 49 years between 1995 and 2014.
The researchers compared women who had never used hormonal contraceptives, those who were current or recent users, and former users.
The majority (86%) of hormonal contraceptive use was related to combined oral products.
The study found that the number of cases of ovarian cancer were highest in women who had never used hormonal contraception (7.5 per 100,000 person years), whereas among women who had ever used hormonal contraception, the number of cases of ovarian cancer were lower (3.2 per 100,000 person years).
The paper said: ‘Compared with “never users”, reduced risks of ovarian cancer occurred with current or recent use and former use of any hormonal contraception. Relative risks among current or recent users decreased with increasing duration.’
It continued: ‘Based on the relative risk for the “never use” versus “ever use” categories of hormonal contraception, the population prevented fraction was estimated to be 21% — that is, use of hormonal contraception prevented 21% of ovarian cancers in the study population.’
The researchers concluded: ‘Use of contemporary combined hormonal contraceptives is associated with a reduction in ovarian cancer risk in women of reproductive age— an effect related to duration of use, which diminishes after stopping use.
‘These data suggest no protective effect from progestogen-only products.’
Links between contraceptives and cancer risk have been the subject of research for many years.
Researcher previously reported that women who used oral contraceptives for 10 years or more had a 45% lower risk of developing ovarian cancer, compared with women who took the pill for a year or less.