Four women in California who died of toxic shock syndrome within a week of taking the controversial abortion pill RU-486 had the same rare bacterial infection, federal officials have confirmed.

The deaths, which occurred between September 2003 and May of this year, were due to the toxic effects of an infection with the highly lethal bacteria Clostridium sordellii. Only 10 previous cases of fatal C. sordellii infections had been reported, with eight of those occurring in women who had given birth to live infants. One other was associated with an abortion, and the remaining one was not associated with pregnancy at all.

The findings are reported in the Dec. 1 issue of The New England Journal of Medicine.

CDC investigator Marc Fischer, MD, MPH, tells WebMD that it is not yet clear if there is something about the abortion pill that makes patients more vulnerable to the rare infection.

He adds that officials with the CDC and the FDA, and outside experts, plan to meet early next year to explore the issue.

“The fact that all four of these cases were due to the same rare bacteria and that they all occurred in California certainly raises a lot of questions,” he says.

The RU-486 abortion pill is known by the brand name Mifeprex. Danco Laboratories -- the maker of Mifeprex -- did not respond to a request for a comment on the findings in time for the publication of this story.

Risks Unknown

The abortion pill was approved for use in the U.S. in 2000 for the termination of early pregnancy, defined as seven weeks' duration or less.

According to Danco Laboratories, more than 460,000 doses of the medication have been distributed in the U.S. since that time.

If the four deaths are the only ones that have occurred after using the drug, it would suggest that less than one in 100,000 women who have used it to induce abortions have died from infection. That is about 10 times higher than the risk associated with surgical abortions performed early in pregnancy, Harvard Medical School obstetrics and gynecology professor Michael F. Greene, MD, tells WebMD.

But it is not clear if the actual risk is higher or lower than this, he says, because there are so many questions that have yet to be answered.

“It is not clear to me or anybody else at this point if there is any real biological or medical link between this method of pregnancy termination and the risk of infection,” he says.

Clustered Cases

The biggest mystery, the experts agree, is why all four cases occurred in a single state. An FDA investigation found no evidence of drug contamination, and it appears that Mifeprex is used with the same frequency and in the same way in California as in other parts of the country, Fischer says.

It is possible that increased media attention in the state has played a role. After his 18-year-old daughter’s death in September 2003, Livermore, Calif., resident Monty Patterson mounted a widely publicized campaign against the abortion pill.

Within days of taking the prescribed dosage of the drug, Holly Patterson experienced bleeding and cramps that were so severe she could hardly walk, according to news accounts. Her boyfriend took her to a hospital emergency department where she was given painkillers and sent home.

Three days later she was rushed back to the hospital, where she died of toxic shock approximately 10 hours later.

If the California cluster is the result of better doctor awareness and reporting, this suggests that the true incidence of Mifeprex-related infections is not known, Fischer says.

The CDC is hoping to raise awareness about the potential risks with the new report. The FDA had the same motive four months ago when it revised the prescribing information for Mifeprex to warn of the risk of fatal infection. Both agencies have also posted information about the four deaths on their web sites.

“Prior to these cases, there really were no reports of serious infection or infection-related death following (drug-induced) abortions,” Fischer says. “Patients and physicians need to know that this is a potential complication, although we believe the risk to be very low.”

What Doctors and Patients Should Know

Identifying C. sordellii infection in women who have had abortions or delivered babies is complicated by the fact that early symptoms tend to be the same as those they would typically experience anyway, such as abdominal cramping, nausea, and vomiting.

The four women who died had quickly developed symptoms including elevated heart rates, low blood pressure, very elevated white blood cell counts, and fluid in the lungs. The infection’s toxic effect on major organ systems (heart, lungs, and kidneys) caused them to fail and caused eventual death.

And, surprisingly, none of the women developed the high fever that is common when the body is fighting infection.

“Patients should be informed of this risk before they consent to the procedure and should be vigilant for symptoms after the procedure,” Greene wrote in an editorial accompanying the CDC report. “[Doctors] must be aware of this potential complication and not be reassured by the absence of fever.”

By Salynn Boyles, reviewed by Louise Chang, MD

SOURCES: Fischer, M. The New EnglandJournal of Medicine, Dec. 1, 2005; vol 353: pp 2352-2360. Marc Fischer, MD, MPH, Fort Collins, Colo. Michael F. Greene, MD, professor of obstetrics, gynecology, and reproductive biology, Harvard Medical School; director of obstetrics, Massachusetts General Hospital, Boston. CNN.com.