Birth Control Shots Impair Memory

Women who use birth control shots may be at an increased risk of suffering memory loss over time, the results of a new study indicate. The investigation was conducted on mice, but scientists say that the results may also be applicable to humans, due to the similarities we share with the rodents.

Birth control shots ironically appeared as an alternative to have to remember to take the pill every single day. This is the first study to identify such a troubling link between commonly-used contraceptives and negative health effects.

Experts with the Bimonte-Nelson Memory and Aging Laboratory at the Arizona State University (ASU), in Tempe, published details of their work in the latest print issue of the esteemed medical journal Psychopharmacology.

The hormone the research team focused on – which is called medroxyprogesterone acetate (MPA) – is present in a wide range of drugs, from the birth control shot Depo Provera to a large number of menopausal hormone therapies.

ASU investigators showed that the chemical causes its adverse side-effects regardless of the method in which it is administered. The team published the first evidence that MPA affects memory in menopausal-aged rats in the November 2010 issue of Neurobiology of Learning and Memory.

The new study was conducted in collaboration with experts from the Barrow Neurological Institute (BNI) and the University of North Texas Health Sciences Center (UNT-HSC). It managed to confirm that the birth control shot version of MPA causes the same effects as the menopausal therapy one.

The researchers wondered “Does it have the same memory-impairing effects if someone takes it as birth control, when they are a younger age?” The work was informed by the fact that some of the researchers' friends were using MPA-based shots as means of contraception.

“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,” Heather Bimonte-Nelson explains.

She holds an appointment as an associate professor of psychology in the ASU College of Liberal Arts and Sciences, and is also the director of the Bimonte-Nelson Memory and Aging Lab at the university.

“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,” ASU psychology doctoral student Blair Braden explains.

“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 the brain,” the expert concludes.

The National Institute on Aging (which is a part of the National Institutes of Health), the state of Arizona, the Arizona Department of Health Services and the Arizona Alzheimer’s Disease Core Center funded the investigation.