Newer Birth Control Pills May Increase Risk of Blood Clots

Researchers found that newer forms of birth control pills, including brands such as Yaz or Yasmin, are more likely to cause blood clots than older versions.

In a recent study led by Yana Vinogradova of the University of Nottingham in England, researchers found that women who took oral contraceptives containing newer types of progesterone hormones such as drospirenone, desogestrol, gestodene, and cyproterone were 1.5 to 1.8 times more likely to develop blood clots. Women who did not use birth control pills were four times less likely to develop blood clots. Women who used birth control pills with older forms of the progesterone hormone like levonorgestrel, norethisterone, and norgestimate, were 2.5 times more likely to develop blood clots.

Regardless of this new finding, researchers want to reassure women that birth control pills are indeed safe. The threefold increased danger of blood clots when using birth control pills is actually much lower than the ten-fold risk a woman has when she is pregnant. The risk of a woman getting a blood clot due to birth control pills is very small. Only one in every 1,000 woman will develop a blood clot per year. However, those with a history of thrombosis have a slightly higher risk.

According to Susan Jick, an epidemiologist at the Boston University School of Public Health, synthetic hormones like drospirenone, which can be found in Yasmin, were created by drug makers who wanted to develop safer hormonal contraceptives for women. The newer progestins, such as desogestrel, norgestimate, and destodene, were created to minimize the adverse effects of older contraceptives such as acne and nausea, all while maintaining good menstrual cycle control.

However, as the study confirmed, that wasn't the case. Jick said, "There were all these reasons one would think they should have been safer. And yet they weren't. People should know that the risk is there."

Just recently, a 21-year-old Australian woman died of blood clots after being on oral contraceptives for only 25 days.

According to the Guttmacher Institute, there are 62 million women in the U.S. in their childbearing years, and about 70 percent of them are at risk of unintended pregnancy. The typical U.S. woman only wants two children, and in order to do so, a woman must use contraceptives for at least 30 years. The most common reason women use oral contraception is to prevent pregnancy, and 58 percent of users also use the pill for health benefits not related to contraception. Furthermore, about 9 percent of pill users have never had sex and use the pill solely for noncontraceptive use.

Dr. Jennifer Wu, an obstetrician/gynecologist at Lenox Hill Hospital in New York City, believes that women must carefully consider both the pros and cons of taking oral contraceptives. "Not only do women have effective pregnancy protection," she says, "they may also enjoy the benefits of lighter and predictable menses. Yet risks of oral contraceptives should also be considered."