Women who use a vaginal ring or skin patch as contraceptive methods are more at risk of a blood clot compared to those who take the second generation of contraceptive pills, according to a large-scale study.
Research published on bmj.com has shown women using the skin patch or a vaginal ring are up to eight times more likely to develop venous thrombosis (blood clots in vein) than women who do not use any type of hormonal contraception.
Women taking the more modern combined oral contraceptive pill containing the hormone levonorgestrel, are just three times more likely to develop a clot.
A team led by Professor Øjvind Lidegaard at the University of Copenhagen reviewed data in Danish non-pregnant women aged 15-49 from 2001 to 2010.
Commenting on the findings, Professor Lidegaard said women aged from 30 upwards who use the vaginal ring or the patch might consider shifting to using the second generation of contraceptive pills.
He said: "The most important thing is that women are informed about the risk. The ring and the patch is approximately double the risk compared with second generation pills.
"If women still prefer to have a ring or a patch, for example because they are not able to remember to take the pill daily, then they can continue. That is their own choice.
"For me, the important thing is that they are informed about the risk."