Doctors have long wondered why pregnant women do not feel the effects of multiple sclerosis when they get pregnant.
By studying mice, researchers found production of the hormone prolactin goes up during pregnancy.
They also found prolactin repairs many damaged nerve cells.
And, they found the same nerve-repairing results when they injected non-pregnant mice with prolactin.
Experts are very encouraged by the research.
They think it may also apply to other ailments, like brain and spinal cord injuries.