Days after posting an article on the probable role of an injectable birth control hormone in spreading AIDS, I read this week that the same stuff may be causing memory loss in middle-aged woman. As if we didn't have enough trouble remembering things already!
How ironic, that the recommended method for women who can't be relied on to remember to take a pill every day should be one that may actually impair their memory.
The synthetic hormone progestin medroxyprogesterone acetate (MPA) is widely used in hormone replacement therapy for menopausal women as well as in injectable contraceptives such as Depo Provera. Arizona State University researcher Heather Bimonte-Nelson and colleagues were doing a rat study on MPA when they discovered that it impaired memory in post-menopausal rodents.
That rang alarm bells for Bimonte-Nelson, who thought about friends taking the same drug as a contraceptive much earlier in life.
"This is an important question, because what we are going to have in our future are women who are menopausal that also have a history of taking MPA as birth control when they were younger," said Bimonte-Nelson.
She and other researchers then set up another rat study specifically to look at the effects on memory of the contraceptive shot. She says:
"What we found was pretty shocking - animals that had been given the drug at any point in their life were memory impaired at middle age compared to animals that never had the drug," said Braden. "We also confirmed that in the subjects that only received the drug when young, the hormone was no longer circulating during memory testing when older, showing it had cleared from the system yet still had effects on brain function."
It seems that MPA acts on a neurotransmitter system called GABA, slowing the brain down too much.
The group plans to follow the animal studies with human trials, and the work is leading to results that could have profound implications for women of all ages.
"This research shows that even after this hormone is no longer on board, months and months later, resulting effects are impacting the brain and its function," Bimonte-Nelson said. "This work is an important step forward in our understanding of the potentially long-lasting effects of clinically used hormones on brain function. However, more research is needed to determine whether these effects also occur in women that take this hormone as birth control or part of hormone therapy."
The recent discoveries about MPA add to its bad history: it has long been associated with bone density loss. Yet many millions of women are encouraged to use it as a contraceptive. When is this going to stop?