An abortion pill that pro-life groups have raised the red flag about for years, especially since the death of a teenager in 2003 who took the drug, received additional warnings by the U.S. Food and Drug Administration yesterday.

Mifeprex, also known as RU-486 or the "abortion pill," can cause serious bacterial infections and bleeding, said the FDA.

Some complications, which can be fatal, can occur without any obvious symptoms, the FDA said in updating the drug's "black box" warning label.

The FDA approved Mifeprex in 2000 for ending early pregnancies of 49 days or less.

"FDA and (maker) Danco Laboratories have received reports of serious bacterial infection, bleeding, ectopic pregnancies that have ruptured, and death, including another death from sepsis (blood infection) that was recently reported to FDA," the agency said in a statement. These reports have led to the revision of the black box labeling.

The FDA said the risks are rare but important to note. The FDA said it will continue to monitor the usage of Mifeprex and may take further action as needed.