Prior research has associated early adolescent use of hormonal contraceptives with the risk of depression in adulthood.
Although hormonal contraceptives may be an effective birth control option for adolescents, researchers from The Ohio State University found their impact on developing brains includes increased levels of the stress hormone corticosterone.
The study of young rats linked the synthetic hormones found in birth control pills, patches, and injections with disordered signal transmission between cells in the prefrontal cortex. This area of the brain continues to develop throughout adolescence. Compared with the control rats, the animals who received hormonal contraceptives produced higher levels of corticosterone, which is similar to cortisol in humans.
The study authors focused on the prefrontal cortex based on prior research that associated early adolescent use of hormonal contraceptives with the risk of depression in adulthood.
“Birth control has had a major positive impact for women’s health and autonomy—so it’s not that we’re suggesting adolescents should not take hormonal contraceptives,” said senior study author Benedetta Leuner, associate professor of psychology at Ohio State, in a press release.“What we need is to be informed about what synthetic hormones are doing in the brain so we can make informed decisions—and if there are any risks, then that’s something that needs to be monitored. Then if you decide to use hormonal birth control, you would pay more attention to warning signs if you knew of any possible mood-related side effects.”
Although hormonal birth control methods are popular, study co-author Kathryn Lenz noted that data are limited regarding how these methods influence the teen brain and behavior. Hormonal birth control methods work by stopping ovaries from producing hormones at levels necessary to produce eggs and making the uterine lining inhospitable for an egg to implant.
“Adolescence is a crucially under-investigated period of dramatic brain change and dramatic hormonal change that we really haven’t understood,” Lenz said in a press release.
The research team administered a combination of synthetic estrogen and progesterone typically found in hormonal contraceptives to female rats for 3 weeks beginning approximately 1 month after they were born, which is an age equivalent to early adolescence in humans. The investigators confirmed that the drugs disrupted the animals’ reproductive cycling.
The blood samples showed the treated rats were producing more corticosterone than untreated animals, which was a sign they were stressed. After being subjected to and recovering from an experimental stressor, the treated rats’ corticosterone level remained high. The adrenal glands were also larger, which suggests their stress hormone production was consistently higher than that of control animals.
The analysis of gene activation markers in the animals’ prefrontal cortex showed a decrease in excitatory synapses in that region of treated rats’ brains compared to controls, but there was no change to inhibitory synapses, which could set up an imbalance of normal signaling patterns and result in altered behavior, according to the study.
In previous research, the loss of only excitatory synapses in the prefrontal cortex has been linked to exposure in chronic stress and depression.
“What this means for the function of particular circuits, we don’t know yet. But this gives us a clue of where to look next in terms of what the functional outcomes might be,” Lenz said in a press release.
Additional studies will focus on targeting the effect of hormonal contraceptives on the brain between puberty and late adolescence, which is a challenging time to study the developing brain because of constant change, according to the study. It is also still questionable as to the reasons behind these drugs’ effects.
“These are synthetic hormones, so are they affecting the brain because of their synthetic properties, or are they affecting the brain because they’re blocking the naturally produced hormones?” Lenz said in a press release. “It’s a difficult question to answer, but an important one.”
How hormonal birth control may affect the adolescent brain. Ohio State University. November 15, 2022. Accessed November 17, 2022. https://news.osu.edu/how-hormonal-birth-control-may-affect-the-adolescent-brain/