If you thought that the FDA’s relative silence about Yaz blood clots meant that the agency had lost interest, think again. Recently, the FDA announced that it “remains concerned” that birth control pills containing drosperinone (i.e., Bayer-made Yaz and Yasmin) could pose a higher risk of blood clots than the pills that don’t contain drosperinone.

In an effort to reiterate that thought, the FDA is also planning to put together an outside panel of medical experts on Dec. 8 so the matter can be discussed thoroughly. So far, the FDA said that the preliminary results of a study that was conducted by an outside agency suggest there is a 1.5-fold increase in the chances of women suffering from blood clots after taking birth control pills that contain drospirenone as opposed to those women taking different types of birth control pills that don’t contain drosperinone. The study was based on data collected from 800,000 women.

Drospirenone is a synthetic progestin that is used in oral contraceptives like Yaz, Yasmin and the generic version, Ocella. While the regulators have been studying these pills, they haven’t yet made a final decision on whether the drugs are more likely to cause blood clots.

The FDA has stated that there is much conflicting information about the blood clot risk linked to drosperinone; officials base that opinion on the results of six previous studies. While some studies say drosperinone-containing pills are more likely to cause blood clots than older pills containing levonorgestrel, there are other studies that dispute that finding. Bayer chooses to follow the studies that claim that drosperionone is no more dangerous than other pills and because of this, the company has been subject to thousands of lawsuits from women and their families who claim that the drug giant didn’t properly warn them of the risks involved in taking Yaz and Yasmin. Those risks include blood clots, deep vein thrombosis, strokes, heart attacks and gallbladder disease.