Sofia Luengo-Woods, Class of 2022
The invention of the birth control pill was revolutionary, giving women all over the world a groundbreaking amount of control over their reproductive plans. As of 2019, 14% of American women from ages 15 to 49 were using the pill (CDC 2020) and only about 42% of those women were using it for purely contraceptive reasons; other common reasons included lessening menstrual pain, treating acne, and reducing the symptoms of endometriosis, a painful disorder where tissue characteristic of the uterus grows outside of it (Guttmacher 2011, Mayo Clinic 2019). While many of the pill’s side effects are favorable, the list of known potential negative side effects continues to grow. In particular, recent observational studies show a correlation between the pill and changes in the brain that make it more vulnerable to certain mental illnesses. Further research on the pill’s effect on the brain must be conducted to measure the severity of these neurological side effects and determine any practical methods for reducing the consequences.
When we talk about “the pill,” we refer to two different kinds of oral contraceptives: the combination pill and the progestin-only pill, also known as minipill. Both are common, but the minipill is preferred for women who are over 35, women who have a history of blood clotting disorders, women who are breastfeeding, and others (Mayo Clinic 2020). The two types have different hormonal compositions and produce different mechanisms for preventing pregnancy. The combination pill contains the sex hormones estrogen and the artificial progesterone, progestin. By keeping estrogen and progesterone levels high, the combination pill mimics pregnancy hormone levels, tricking the body into suppressing its natural ovulation (Nottke 2008). The minipill, on the other hand, only contains progestin. It doesn’t always suppress ovulation; instead, it thickens the cervical mucus and thins the lining of the uterus, effectively preventing sperm from reaching the egg (Mayo Clinic 2020).
Due to the nature of hormonal treatments, side effects are inevitable. Because it is difficult to pinpoint the target of the newly introduced hormones, they often affect the body in unintended ways. For example, the increase in estrogen and progesterone caused by the combination pill also lowers the levels of androgen hormones, thus often reducing the acne associated with androgens (Scripps 2020). Differences in side effects between the two types of pills are common; since they contain different hormones, their effect on the body will be different. Other common side effects for the combination pill include (but are not limited to) less-severe menstrual cramps, lighter menstrual bleeding, migraine relief, bloating, and nausea (Mayo Clinic 2019). Side effects of taking the minipill may include ovarian cysts, decreased libido, weight gain, and extra hair growth on the face, chest, and back (Mayo Clinic 2020).
While many possible side effects of the pill are known, researchers have only recently begun looking at the pill’s potential side effects on the brain. A recent study examined the relationship between the use of the pill during adolescence and the brain’s response to stress. Puberty and adolescence are a critical period of brain development, and the study’s results suggest that taking the pill during that time is related to a blunted stress response in the brain. The same study found that use of the pill in general is linked to structural changes in brain regions involved in memory and emotion, providing a mechanism for previous results that found women on hormonal birth control, including those on the pill, were less likely to remember details relating to emotional stories (Sharma et al. 2020, Nielson et al. 2014). Altogether, these findings demonstrate that taking the pill, especially in adolescence, may lead to the development of an abnormally low stress response, especially in regards to emotion. Other studies have linked blunted stress responses in women to depressive symptoms (Burke et al. 2005) and PTSD (Metz et al. 2020). It is entirely possible, although not yet determined, that the pill increases vulnerability to those stress-related mental illnesses; future research in this area may be able to minimize these potential effects of the pill.
Another study had similar results, concluding that women who take the pill were found to have hypothalami 6% smaller than women who do not take it (Gordon 2019). The hypothalamus is a brain area vital for producing hormones to help regulate essential bodily functions, including mood and the stress response. The same study also found that smaller hypothalami are associated with increases in anger and a higher risk of developing depressive symptoms (Morley and Brooks 2019). Another study had found that decreased hypothalamus volume is associated with generalized anxiety disorder, indicating its link to an abnormal stress response (Terlevic et al. 2013). Once again, we see that brain changes associated with birth control also have connections to mental illness.
Hormone shifts in the body are to be expected when taking any kind of hormonal treatment, but the aforementioned studies provide some evidence for actual structural changes in the brain, each related to the stress response and the processing of emotional information. The results are startling, but it is important to remember that the studies conducted here were correlational; no causal relationships were established. Even so, they highlight the need for further research in the area by demonstrating how much we still don’t know about the effect of the pill on the brain.
The current state of research on the neurological side effects of the pill is lacking in two major areas. Firstly, longitudinal-experimental studies are needed to both potentially establish causality and give us a greater understanding of the long-term effects of taking the pill. To this point, no research has provided causal evidence that taking the pill can result in structural changes in the brain; an experimental set-up is needed in order to find out whether or not the pill truly causes them. The longitudinal aspect of the studies would allow us to track the changes, or the lack thereof, in the brain, and whether or not any changes are reversible. The results of such an experiment would give us a much greater understanding of both hormonal birth control and the brain, potentially paving the way for future development in birth control technology.
Secondly, none of the studies described in this article differentiate between the combination pill and the minipill, instead lumping them together under the umbrella of oral contraceptives. The two types of pills have different hormonal compositions and often different side effects, so it stands to reason that their effects on the brain would be different as well. However, current research on oral contraceptives and the brain overlooks this fact, limiting the conclusions we can draw from these studies. Differentiating between the two types of pills in future research will help our understanding of the effects of estrogen and progesterone on the brain. If any stress-related side effects of each pill are established by future experiments, it would surely factor into the decisions of millions of women when choosing between contraceptive options.
This article is not intended to scare anyone away from taking the pill; oral contraceptives remain absolutely safe and effective. In fact, the author of the hypothalamus volume study himself emphasized that his results were preliminary, stating that “there isn’t enough data here for anyone to worry” (Gordon 2019). The goal of this article is to instead point out the lack of certain types of research in the area, the potential for birth control development, and the need for understanding the pill’s side effects on the brain. Present research points towards an abnormal stress response as a possible side effect of the pill, which has large scale implications for womens’ mental health. The pill has given millions of women the freedom to choose their reproductive path, and further research in the area will only help them make better-informed decisions.
When we talk about “the pill,” we refer to two different kinds of oral contraceptives: the combination pill and the progestin-only pill, also known as minipill. Both are common, but the minipill is preferred for women who are over 35, women who have a history of blood clotting disorders, women who are breastfeeding, and others (Mayo Clinic 2020). The two types have different hormonal compositions and produce different mechanisms for preventing pregnancy. The combination pill contains the sex hormones estrogen and the artificial progesterone, progestin. By keeping estrogen and progesterone levels high, the combination pill mimics pregnancy hormone levels, tricking the body into suppressing its natural ovulation (Nottke 2008). The minipill, on the other hand, only contains progestin. It doesn’t always suppress ovulation; instead, it thickens the cervical mucus and thins the lining of the uterus, effectively preventing sperm from reaching the egg (Mayo Clinic 2020).
Due to the nature of hormonal treatments, side effects are inevitable. Because it is difficult to pinpoint the target of the newly introduced hormones, they often affect the body in unintended ways. For example, the increase in estrogen and progesterone caused by the combination pill also lowers the levels of androgen hormones, thus often reducing the acne associated with androgens (Scripps 2020). Differences in side effects between the two types of pills are common; since they contain different hormones, their effect on the body will be different. Other common side effects for the combination pill include (but are not limited to) less-severe menstrual cramps, lighter menstrual bleeding, migraine relief, bloating, and nausea (Mayo Clinic 2019). Side effects of taking the minipill may include ovarian cysts, decreased libido, weight gain, and extra hair growth on the face, chest, and back (Mayo Clinic 2020).
While many possible side effects of the pill are known, researchers have only recently begun looking at the pill’s potential side effects on the brain. A recent study examined the relationship between the use of the pill during adolescence and the brain’s response to stress. Puberty and adolescence are a critical period of brain development, and the study’s results suggest that taking the pill during that time is related to a blunted stress response in the brain. The same study found that use of the pill in general is linked to structural changes in brain regions involved in memory and emotion, providing a mechanism for previous results that found women on hormonal birth control, including those on the pill, were less likely to remember details relating to emotional stories (Sharma et al. 2020, Nielson et al. 2014). Altogether, these findings demonstrate that taking the pill, especially in adolescence, may lead to the development of an abnormally low stress response, especially in regards to emotion. Other studies have linked blunted stress responses in women to depressive symptoms (Burke et al. 2005) and PTSD (Metz et al. 2020). It is entirely possible, although not yet determined, that the pill increases vulnerability to those stress-related mental illnesses; future research in this area may be able to minimize these potential effects of the pill.
Another study had similar results, concluding that women who take the pill were found to have hypothalami 6% smaller than women who do not take it (Gordon 2019). The hypothalamus is a brain area vital for producing hormones to help regulate essential bodily functions, including mood and the stress response. The same study also found that smaller hypothalami are associated with increases in anger and a higher risk of developing depressive symptoms (Morley and Brooks 2019). Another study had found that decreased hypothalamus volume is associated with generalized anxiety disorder, indicating its link to an abnormal stress response (Terlevic et al. 2013). Once again, we see that brain changes associated with birth control also have connections to mental illness.
Hormone shifts in the body are to be expected when taking any kind of hormonal treatment, but the aforementioned studies provide some evidence for actual structural changes in the brain, each related to the stress response and the processing of emotional information. The results are startling, but it is important to remember that the studies conducted here were correlational; no causal relationships were established. Even so, they highlight the need for further research in the area by demonstrating how much we still don’t know about the effect of the pill on the brain.
The current state of research on the neurological side effects of the pill is lacking in two major areas. Firstly, longitudinal-experimental studies are needed to both potentially establish causality and give us a greater understanding of the long-term effects of taking the pill. To this point, no research has provided causal evidence that taking the pill can result in structural changes in the brain; an experimental set-up is needed in order to find out whether or not the pill truly causes them. The longitudinal aspect of the studies would allow us to track the changes, or the lack thereof, in the brain, and whether or not any changes are reversible. The results of such an experiment would give us a much greater understanding of both hormonal birth control and the brain, potentially paving the way for future development in birth control technology.
Secondly, none of the studies described in this article differentiate between the combination pill and the minipill, instead lumping them together under the umbrella of oral contraceptives. The two types of pills have different hormonal compositions and often different side effects, so it stands to reason that their effects on the brain would be different as well. However, current research on oral contraceptives and the brain overlooks this fact, limiting the conclusions we can draw from these studies. Differentiating between the two types of pills in future research will help our understanding of the effects of estrogen and progesterone on the brain. If any stress-related side effects of each pill are established by future experiments, it would surely factor into the decisions of millions of women when choosing between contraceptive options.
This article is not intended to scare anyone away from taking the pill; oral contraceptives remain absolutely safe and effective. In fact, the author of the hypothalamus volume study himself emphasized that his results were preliminary, stating that “there isn’t enough data here for anyone to worry” (Gordon 2019). The goal of this article is to instead point out the lack of certain types of research in the area, the potential for birth control development, and the need for understanding the pill’s side effects on the brain. Present research points towards an abnormal stress response as a possible side effect of the pill, which has large scale implications for womens’ mental health. The pill has given millions of women the freedom to choose their reproductive path, and further research in the area will only help them make better-informed decisions.
References:
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Birth control may alter part of women’s brains [Internet]. US News & World Report; [cited 2020 Nov 28]. Available from: https://www.usnews.com/news/health-news/articles/2019-12-04/birth-control-pill-may-al ter-part-of-womens-brains
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Postlearning stress differentially affects memory for emotional gist and detail in naturally cycling women and women on hormonal contraceptives. Behav Neurosci [Internet]. [cited 2020 Nov 28];128(4):482–493. Available from: https://doi.org/10.1037/a0036687
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Terlevic R, Isola M, Ragogna M, Meduri M, Canalaz F, Perini L, Rambaldelli G, Travan L, Crivellato E, Tognin S, et al. 2013.
Decreased hypothalamus volumes in generalized anxiety disorder but not in panic disorder. J Affect Disord [Internet]. [cited 2020 Dec 8];146(3):390–394. Available from: https://www.sciencedirect.com/science/article/pii/S0165032712006568?casa_token=EfZ 6ErFuJCoAAAAA:jwtMXwqjXp5VMkfBGBj7AR58grlDVbEtUaR-Qt2R35ILoU5-VR D38S52CwkZfof01DHc3mPai9A
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