Raleigh, N.C. — The 400,000 Americans who have multiple sclerosis treat their symptoms with prescription drugs, but a hormone produced by pregnant women may be more effective for female sufferers.

Paula Lizzotte found her symptoms – muscle weakness, pain and vision problems – eased during her pregnancy. "I actually had a little more energy, could concentrate a little bit better and (was) ... overall feeling better," she recalled.

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

It's actually a well-known phenomenon. Research credits 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. Now researchers are investigating if it can work in women who aren't pregnant.

In a pilot study, 10 women got the hormone – and got excellent results. The next step is to test the hormone on a larger population – this time 150 women.

Dr. Giesser is hopeful. "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."

Lizzotte's symptoms have returned since the birth of her child, but she said the new research creates hope for her and thousands of other women with MS.

Unfortunately, male sufferers of MS are left out. Since estriol is a female hormone, it won't work in men.