User:Pvpmd/Combined hormonal contraception

Adverse effects
Although the risk of venous thromboembolism, arterial thromboembolism, breast cancer and cervical cancer in CHC users is small, all CHCs are associated with higher risks of these compared to no use. Given that the vast majority of the studies evaluating these associations have been observational studies, causation between CHC use and these conditions is unable to be determined. All CHCs are associated with an increased incidence of venous and arterial thromboembolism. However, those containing higher doses of estrogen are associated with an increase in venous and arterial thromboembolism. In addition, some formulations of progesterone, including gestodene, desogestrel, cyproterone acetate and drospirenone, in combination with estrogen, have been associated with higher rates of venous thromboembolism compared to formulations containing a type of progesterone called levonorgestrel.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2621397/