Doctors have long thought that estrogen supplements increased the risk of stroke in women. But Mayo Clinic researchers recently found that before age 50, estrogen can actually help prevent strokes.

The researchers looked at a recent Mayo Clinic study, and compared it with six other studies of women from around the world. What they found surprised them, and they now urge doctors to revamp their thinking about estrogen and the brain.

The findings would apply to women with premature or early menopause. The average age for women to experience menopause is 50. Women who experience premature menopause (before age 40) or early menopause (before age 45), either naturally or as a result of removal of the ovaries, would likely benefit from taking supplemental estrogen, according to the findings, which were published in the medical journal Menopause.