News

17-12-2017

A recent television report featured women discussing significant side-effects they believed to have been caused by long-acting reversible contraceptives use such as implanon and the intrauterine system ( Mirena), was unbalanced and failed to present the experience of most women, for whom the devices provide significant benefit, reduced period bleeding and pain and reliable protection from pregnancy

Unfortunately for young women needing contraception, a study was also released of 1.8 million Danish women followed from 1995 to 2012 demonstrating a higher risk of breast cancer in women who are  using hormonal contraceptive compared to women who are not using them. ( NEJM, Dec 7, 2017) During the 11 years of the study, less than 1% of the study population of 1.8 million women were diagnosed with breast cancer.

The very small link between the older versions of the oral contraceptive and breast cancer has long been recognised from research out of Oxford following women taking the pill in the 60's, 70's and 80's. The Danish researchers wanted to determine if newer forms of contraception with different progestogen combinations , including the IUCD and implanon carried a similar risk.

Breast cancer is rare in young women, the absolute extra risk of breast cancer associated with the use of hormonal contraception among all women aged 15-49 was 1.3 per 10, 000 or one extra breast cancer for every 7690 women using hormonal contraception for one year. The study found little evidence of consistent differences is risk between users of combined oral contraceptives with different and newer progestogens. The actual risk of breast cancer to an individual woman is tiny and the risk rapidly declines once the woman stops using the hormonal contracetion.

Among women under 35 years, the increase in cancer risk is one for 50,000 users as the background incidence of breast cancer is very low in young women, and the incidence starts to climb as women get into their late 30s and 40s. It might be that women in their late 30s and 40s should discuss non-hormonal forms of contraception with their doctor.

Researchers did not detect an increased risk in former users who had used hormonal contraception for less than five years and the long term risk for those who had been contraceptive users for more than five to ten years gradually decreased after stopping.

Women who has ever used the pill were less likely to have colorectal, endometrial or ovarian cancer, the benefits lasting for many years, perhaps thirty or more.

The study used a large, nationwide population of women in Denmark, but not able to adjust for factors known to be associated with developing breast cancer, such as alcohol intake, activity and whether they breast fed. Information on weight was known for only 30%, the study design is a cohort study and the results are only able to demonstrate an association, not cause and effect 

 

Regarding the progesterone only methods of contraception such as Implanon and Mirena, ( known as Long acting reversible contraceptives, LARCs) which are often be prescribed to women who are unable to use oestrogen containing contraception, an increase in breast cancer was also demonstrated at similar tiny rates. ( one extra breast cancer case for every 7,690 women using hormonal contraception over one year)

Large patient trials have consistently found the progesterone-only devices to be safe and highly effective at preventing pregnancy. A large study in the US ( the CHOICE study, published by the American College of Obstetrics and Gynaecology August 2010) involved more than 7000 women and demonstrated more than two thirds of women chose a LARC method, with high levels of satisfaction and continuation.  The World Health Organisation supports strategies to increase their uptake and both the US and the UK governments have increasing access to LARC methods a health priority as the body of evidence in favour of their use and safety is so strong, Thousands of women are spared anaemia, the hysterectomy rate has reduced by 3-fold,

The RANZCOG supports the use of LARC as safe and effective, and following the television broadcast,  issued a statement to that effect and that women should be given balanced advice about the advantages and disadvantages of the different contraceptive methods in order to make an informed choice.

International consensus supports the safety and efficiency of LARC as the most effective public health strategy to address the impact economically, socially, psychologically and physically to all aspects of women's lives.

The individual woman must have a discussion with her doctor involving the individual risks and benefit of the different contraceptive methods, and these risks and benefits will alter according to lifestyle, age and other factors that must be considered.

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