A new study from Argentina finds a link between birth control pills and the development of multiple sclerosis.
Researchers at the Raul Carrera Institute for Neurological Research in Buenos Aires identified 305 women previously diagnosed with MS. They compared them to more than 3,000 other women who did not have MS.
"They saw a slightly increased risk of having MS if they were on at least three months of hormonal-based contraceptive or birth control," said Dr. Mary Rensel, who did not take part in the study but treats MS patients at Cleveland Clinic.
Results show women who had used hormonal contraceptives were 35 percent more likely to develop MS than those who did not use them. The majority used estrogen/progestin combinations.
"There are a lot of things that seem to go into, what we call, autoimmune diseases -- MS is one of those," Rensel said. "We actually do not know the cause of MS. There seems to be contributors. There's genetics, there's environments, there's somebody's weight, and maybe medications that they've taken we don't know that for sure."
Dr. Corrina Steiger, president of the National Multiple Sclerosis Society of North Florida, said while the details of the study are new, knowledge of a possible connection between hormones and MS is not.
"The National Multiple Sclerosis Society more than 10 years ago knew that gender in MS is an area we really need to focus research on," Steiger said. "So we've been studying gender and MS for a long time, specifically hormones."
Researchers say the findings suggest using hormonal contraceptives may be contributing, in part, to the rise in the rate of MS among women. Rensel said more studies are needed.
"I would say this study doesn't show us enough change that we would say, 'Oh, everybody get off.' These things, you know, it just shows us that maybe we need to be aware, more studies need to be done to look into the effects of hormones and the risk of having MS someday," Rensel said.
Steiger said while the cause of MS is still unknown, there are many factors that seem to contribute, like genetics, environments, weight and maybe medications, all areas the National MS Society is currently researching.
She said even more research will need to be done before its determined that birth control is a risk factor for MS or one of many.
"You really need to talk to your doctor," Steiger said. "There is no significant evidence saying that you should or should not take birth control if you're on MS, or if you have MS or don't have MS."