Bearing a child seems to have the unlikely effect of sending multiple sclerosis in remission – a new Canadian study might throw some light on this mystery.

Researchers at the University of Calgary made a significant discovery: a certain hormone produced during pregnancy rebuilds myelin, the crucial protective coating of the brain. The disintegration of myelin generates MS.

The researchers hope that prolactin, a hormone that triggers milk production during pregnancy, could one day be used as treatment for MS patients.

The deterioration of myelin (on the brain and spinal cord) causes other neurological conditions besides multiple sclerosis, such as stroke, spinal cord injuries and some dementia, says the Calgary research team. Prolactin could be used to treat these too.

The research was done with mice, not humans, and thus should be viewed with caution, the team warns.

They found twice as much myelin repair in pregnant female mice with spinal cord injuries compared with non-pregnant females of the same age. They also discovered that giving prolactin to mice that weren't pregnant also repaired the nerve coating.

"It blew us out of the water,"� said Dr. Samuel Weiss, one of the lead authors. Dr. Weis and Dr. Wee Young published their study in today's edition of Journal of Neuroscience. “Right now there is nothing else that can stimulate myelin repair.... The potential is very significant.�

The research opens up a new approach to treating MS, as current treatments focus on controlling the autoimmune disease, but don't repair damage that has occurred. “These are hopeful times for MS treatment," said co-author Dr. Wee Young, a neuroscientist. “We have a new insight on how to repair lesions that already exist.�

MS attacks the coating of insulation around nerves which is myelin, creating lesions that disrupt nervous system messages. This damages everything from eyesight to mobility.

Previous research has focused on what role pregnancy plays in stopping the immune system attacks, but the team of Calgary researchers had a different approach: they discovered pregnancy was also associated with the production of new nerve coating.