In a new study, researchers find new types of combined oral contraceptives (containing both lower doses of estrogens and newer progestogens) are linked to a reduced risk of ovarian cancer in young women.
This positive effect strengthened with longer periods of use and persisted for several years after stopping.
The study is conducted by the University of Aberdeen in Scotland and the University of Copenhagen in Denmark.
At least 100 million women worldwide are using hormonal contraception every day.
Previous research has shown a reduced risk of ovarian cancer in women who take combined oral contraceptives, but most of the evidence relates to the use of older products, containing higher levels of estrogen and older progestogens.
Women who use newer oral contraceptives and other hormonal contraceptive methods also want to know whether they are likely to experience the same benefit.
In the current study, the researchers examined the influence of newer hormonal contraceptives (combined and progestogen-only products) on overall and specific types of ovarian cancer in women of reproductive age.
Using national prescribing and cancer registers, they analyzed data for nearly 1.9 million Danish women aged 15-49 years between 1995 and 2014.
Women were categorized as never users (no record of being dispensed hormonal contraception), current or recent users (up to one year after stopping use), or former users (more than one year after stopping use) of different hormonal contraceptives.
The data showed that most (86%) of the hormonal contraceptive use related to combined oral products.
The team found that the number of cases of ovarian cancer was highest in women who had never used hormonal contraception (7.5 per 100,000 person-years).
But among women who had ever used hormonal contraception, the number of cases of ovarian cancer was 3.2 per 100,000 person-years.
There was no firm evidence to suggest any protective effect among women who used progestogen-only products.
But the researchers point out that few women were exclusive users of these products. This limits the ability to detect an effect.
The reduced risk for combined products was seen with nearly all types of ovarian cancer, and there was little evidence of important differences between products containing different types of progestogens.
Similar results were also found among women followed up to their first switch in contraceptive type.
Based on these findings, the researchers say that hormonal contraception prevented an estimated 21% of ovarian cancers in this group of women.
The team suggests that contemporary combined hormonal contraceptives are linked to a reduced risk of ovarian cancer in women of reproductive age, with patterns similar to those seen with older combined oral products.
The study is published by The BMJ.
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Source: The BMJ.