HealthDay News — Newer formulations of combined oral contraceptives pills (OCPs), such as Yaz, Yasmin, and Desogen, are associated with a higher risk of venous thromboembolism than older versions, according to research published in The BMJ.
A team led by Yana Vinogradova, of the University of Nottingham in the United Kingdom, analyzed two large U.K. patient databases. The investigators looked specifically at venous thromboembolism risk among women aged 15 to 49 taking combined OCPs.
The researchers reported that women who used OCPs with newer types of progestogen hormone — drospirenone, desogestrel, gestodene, and cyproterone — were 1.5 to 1.8 times more likely to develop venous thromboembolism than those who used OCPs containing older progestogens such as levonorgestrel, norethisterone, and norgestimate. Compared to a control group, those who used the newer OCPs were four times more likely to develop venous thromboembolism, and those who used the older OCPs were 2.5 times more likely to develop venous thromboembolism.
Still, the risk to any one woman remained low. In absolute terms, the extra number of venous thromboembolism cases per year per 10,000 women was six for women using OCPs with levonorgestrel and norgestimate, compared to 14 for those using newer OCPs with desogestrel and cyproterone, the researchers said.
Vinogradova’s team emphasized that birth control pills are safe, and pointed out that even the three-fold increased risk of venous thromboembolism associated with OCPs is still lower than the 10-fold increased risk that a woman experiences when she is pregnant.