This is a statement from the FSRH on a study recently published on risks with COC use. This study looks at how the different dose of oestrogen and how the different progesterone affect the risk of PE, CVA and MI. Bottom line - we should be advising women choosing the COC that a 20mcg ethinylestradiol/levonorgestrel pill may have lower thrombotic risks (though there is no such pill available in the UK at present).
The study showed that:
- levonorgestrel containing pills have a lower risk of PE than desogestrel and gestodene containing pills.
- 20mcg ethinylestradiol containing pills have a lower risk of PE, ischaemic CVA and MI than pills containing more oestrogen.
How significant is this?
The results are significant. However, the absolute levels of risk are low and the study didn't look at the background risks in the population.
It was an observational study, so there may be prescribing bias. There was also no consideration of BMI, BP or smoking status, which are significant confounders.
Should this alter our practice?
Firstly there are no 20mcg ethinylestradiol/levonorgestrel pills available in the UK.
FSRH advises that women choosing a COC 'should be advised' that a 20mcg ethinylestradiol/levonorgestrel pill may be associated with lower venous and arterial thrombotic events.
It is still perfectly acceptable to use other pills where needed by the individual.