LOS ANGELES (CBS) — Researchers say women who take newer versions of birth control pills are more likely to develop blood clots.

The chemical drospienone – which can be found in popular contraceptive pills such as Yasmin, Yaz and Ocella – can be more dangerous than other hormones.

Women taking pills with drospienone are reportedly two to three times more likely to develop blood clots than those taking pills containing levonorgestrel.

However, researchers say the risk for blood clots is still very low and women should talk to their doctors about any potential side effects.

The study is published in the online version of the British Medical Journal.