PHOENIX, Arizona, November 7, 2011 (LifeSiteNews.com) - Research at Arizona State University (ASU) has found that the synthetic progestin hormone medroxyprogesterone acetate (MPA), used in the injectable contraceptive Depo Provera, is linked to memory loss.

Psychology doctoral student Blair Braden and Heather Bimonte-Nelson, associate professor of psychology in the College of Liberal Arts and Sciences and director of the Bimonte-Nelson Memory and Aging Lab at ASU, led the study.

This study was an extension of earlier research carried out by Braden that implicated MPA used as a component of hormone therapy for menopause to possible detrimental cognitive effects in women.

This earlier study, published in 2010 in Neurobiology of Learning and Memory, showed that MPA impaired memory in menopausal-aged rats.

The current study specifically looked at MPA in relation to the Depo Provera birth control injection.

In a press release from ASU, Bimonte-Nelson said she and Braden began asking questions about the effects of the drug because Braden was concerned about friends taking MPA as a contraceptive, and wondered whether the drug would have the same memory-impairing effects when taken by young women.

“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.

The study involved three groups of rats that received doses of MPA at varying ages, plus a control group that did not receive the hormone.

The researchers explained that the first group only received MPA as young adults, to model birth control. The second only received it post-menopausal to model hormone therapy. The third group received it at both young adulthood and maturity, to model women who used it for birth control and as a post-menopausal hormone therapy.

The rats’ memories were tested by placing them in water-based mazes to swim and seek out hidden platforms in the water.

“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. 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,” said Braden.

“This research shows that even after a hormone is no longer on board, months and months later, after the reproductive cycle has gone through many phases, there are still changes occurring that are clearly impacting the brain and its function,” said Bimonte-Nelson.

The researchers indicated that they plan to follow the animal studies with human trials, and pointed out that their work is leading to results that could have profound implications for women of all ages.

“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,” Bimonte-Nelson concluded.

Depo-Provera was approved for use in the United States in October 1992. In June of 1993, however, Canada’s Department of Heath and Welfare prohibited the use of Depo-Provera, saying that the drug did not meet Canadian safety standards as a contraceptive.

A fact sheet from Human Life International (HLI) notes that Depo-Provera inhibits ovulation and thickens cervical mucus, both of which are contraceptive actions, but also acts as an abortifacient by altering the lining of the uterus (the endometrium) to inhibit implantation of the blastocyst or newly conceived child.

The study, titled “Cognitive-impairing effects of medroxyprogesterone acetate in the rat: independent and interactive effects across time” will be published by the journal Psychopharmacology.

An abstract published online ahead of print is available here.