A study on rats shows that hormonal contraceptives are associated with impaired transmission of signals between brain cells and increased stress.
- Hormonal birth control can take the form of a pill, patch or implant.
- In France, contraception is free for women under 26.
The pill is the method of contraception most used by adolescent girls, according to figures from theHealth Insurance. This hormonal contraception is considered safe and effective by health professionals, but scientists question its effects on young women. Researchers from the University of Ohio, in the United States, present the results of a study on this subject carried out with rats.
Why focus on the effects of hormonal contraceptives on adolescent girls?
“Not much is known about how hormonal control of fertility influences the brain and behavior of teenage girls“, estimates the co-author of this research Kathryn Lenz, associate professor of psychology at Ohio State. “Adolescence is a vastly understudied time in terms of brain and hormonal changes“Along with the other authors, they recognize the positive impact of hormonal contraceptives on women’s health and autonomy.”What we need is to know the effects of synthetic hormones on the brain so that we can make informed decisions.” says lead author Benedetta Leuner, an associate professor of psychology at Ohio State.
A study on the effects of hormonal contraceptives on the brains of rats
To better understand the effects of these contraceptives, the researchers used laboratory rats. They gave a combination of synthetic estrogen and progesterone to female rats for three weeks, about a month after birth, which is equivalent to early adolescence in humans. The drugs had a contraceptive effect: they disrupted the rodents’ reproductive cycle. Blood tests showed that the treated rats produced more corticosterone than the untreated animals, which means they were stressed. Their adrenal glands were also bigger,”suggesting that their production of stress hormones was consistently higher than that of control animals.”observe the authors.
Future research on hormonal contraception
In the brain, the researchers also found changes: “An analysis of gene activation markers in the animals’ prefrontal cortex showed a decrease in excitatory synapses in this brain region in treated rats compared to controls, they observe. (…) The loss of only excitatory synapses in the prefrontal cortex has been linked to exposure to chronic stress and depression in previous research.” Signal transmission between brain cells in the prefrontal cortex area was also disrupted in the treated rats, but this area “continues to develop throughout adolescence“. In the near future, the authors of the study wish to further their research to understand whether the effects observed are related to contraception in itself or to the blocking of natural hormones.
