(CBS) — It's estimated some 400,000 Americans have multiple sclerosis or MS. Current drugs can help the condition but researchers now believe a hormone produced by pregnant women may be a more effective treatment.

For years Paula Lizotte's multiple sclerosis caused muscle weakness, pain and vision problems. But things changed when she got pregnant.

It's actually a well known phenomenon.

“Women with MS tend to have less relapses and generally do well while they're pregnant,” explained Dr. Barbara Giesser of the UCLA Medical Center.

"I actually had a little more energy, could concentrate a little bit better and general overall feeling better,” Lizotte said.

Researchers say the reason is a hormone produced during pregnancy called estriol.

Multiple sclerosis causes symptoms by damaging the nerve fibers that carry brain signals.

Estriol seems to protect against this process and now researchers want to see if it can work in women who aren't pregnant.

In a pilot study the hormone was given to 10 women with excellent results. Now researchers are starting a larger trial, testing estriol on 150 non-pregnant patients. But results will take time.

"I think people should be hopeful and I think that the expectations are that we will have a whole new wave of better drugs and possibly more effective drugs within the next three to five years,” said Dr. Giesser.

Paula is one of the hopeful. Since her daughter's birth some MS symptoms have returned.

"A lot of us are willing to try anything to feel better,” she said.

Since estriol is a female hormone it won't work in men. But for Paula and thousands of other women with MS it may someday help.