Birth Control Pills Affect Memory
by Rallie McAllister, MD, MPH
If you’ve ever taken the Pill, you may have noticed that it changes the way you feel, physically and emotionally. The results of a new study* suggests that taking the Pill may also affect your memory.
Researchers at University of California, Ervine, found that women who use birth control pills experience memory changes, and they’re not all bad. The researchers found that women using oral contraceptives were better able to remember the gist of an emotional event, but women who weren’t using the Pill were able to retain details better. These findings will interest a lot of women, since more than 100 million women worldwide currently use the Pill.
For the study, women were divided into groups—those who were taking oral contraceptives and those experiencing natural hormonal cycles. The groups of women were shown photographs of a mother, her son, and a car accident. The audio narrative differed; some women in each group were told that the car had hit a curb, while others were told the car had hit the little boy and critically injured him.
A week later, all of the women were given a surprise test about what they recalled. Women who had been using hormonal contraceptives for as little as one month remembered more clearly the main events in the accident. Women who weren’t using oral contraceptives remembered more of the details—that there had been an accident, that the boy had been rushed to the hospital, that doctors worked to save his life and successfully reattached both his feet, and that there was a fire hydrant next to the car.
The changes in memory—which aren’t permanent—occur because contraceptives suppress sex hormones, such as estrogen and progesterone, to prevent pregnancy. Previous studies show that these hormones impact the ways in which we think and remember.
The researchers believe the findings of the study could help scientists understand why women experience post traumatic stress syndrome more frequently than men, and how men remember events differently than women. Men typically retain the gist of events better than they retain the details. Women on the Pill, who have lower levels of hormones associated with female reproduction, may remember emotional events more like men than like women who are cycling normally.
*Shawn E. Nielsen, Nicole Ertman, Yasmeen S. Lakhani, Larry Cahill. Hormonal contraception usage is associated with altered memory for an emotional story. Neurobiology of Learning and Memory, 2011; 96 (2): 378 DOI: 10.1016/j.nlm.2011.06.013