The uterus may play a role in memory

The uterus is best known for its baby-growing job. But the female organ may also have an unexpected role in memory, a study in rats suggests.

The results, published online December 6 in Endocrinology, counter the idea that the nonpregnant uterus is an extraneous organ. That may have implications for the estimated 20 million women in the United States who have had hysterectomies.

In the study, female rats either underwent removal of the uterus, ovaries, both organs or neither. Six weeks after surgery, researchers led by behavioral neuroscientist Heather Bimonte-Nelson of Arizona State University in Tempe began testing the rats on water mazes with platforms that were hidden just below the surface.

Compared with the other groups, rats that lacked only a uterus were worse at remembering where to find the platforms as the tests turned progressively harder. The results suggest that signals that go from the uterus to the brain are somehow involved in remembering multiple bits of information at the same time.

Rats lacking just a uterus had differences in their hormone levels, too, even though these rats kept their hormone-producing ovaries.

Researchers have known for decades that hormones released by the ovaries can influence the brain. But finding that the uterus on its own can influence memory is a surprise, says neuroendocrinologist Victoria Luine of Hunter College of the City University of New York. Because many women have their uteruses removed but keep their ovaries, “this revelation brings up some interesting questions to explore.”

Still, the results are too preliminary to change clinical practice, says neuroscientist and reproductive endocrinologist Natalie Rasgon of Stanford University. The rats in the study were never pregnant, and it’s unclear whether the results would translate to women who have given birth, for instance.