WASHINGTON, D.C., June 1, 2011 ( – Federal drug regulators are now reviewing studies that say some modern birth control pills may pose a serious risk of clots to women who take them.

The US Food and Drug Administration (FDA) announced Tuesday that they were conducting a safety review of birth control products containing drospirenone, a synthetic female sex hormone or progestin.

German pharmaceutical maker Bayer’s oral contraceptives Yaz, Yasmine, Safyral, Beyaz, and their generics are part of a chemical family of contraceptives containing drospirenone, and are among the oral contraceptives whose effects the FDA intends to review.

Bayer faces 7000 Yaz-related lawsuits from women who say the drug-manufacturer misrepresented the dangers associated with using the birth control pills – side effects including stroke, cardiac arrest, blood clots, and gallbladder problems.

Bayer has marketed heavily its Yaz oral contraceptive products to teenagers and young adult women, saying its products were not just for preventing pregnancy, but also could treat PMS symptoms and acne.

One wrongful death lawsuit involves an 18-year-old New Jersey college student, Michelle Pfleger, who died of cardiac arrest after taking Yaz for acne treatment. A blood clot had lodged in her lungs resulting in her sudden death on her way to classes on September 24, 2010. Her mother Joan Cummins filed suit against Bayer on May 10.

The FDA noted in its public announcement that “[a]ll birth control pills pose a risk of blood clots,” but two studies posed in the British Medical Journal contended that the contraceptives containing drospirenone posed two to three times a greater risk than other contraceptives containing the progestin levonorgestrel.

The FDA said it was going to conduct a study of 800,000 women in order to resolve the conclusions of conflicting studies on drospirenone-containing contraceptives. The results of the study are due sometime in the summer.