Menstrual Cycles and Concussion: Late Adolescent and Childbearing Years

While childbearing age can be identified as the time between mid-adolescence and menopause, I’m going to make a smaller distinction here. In mid-adolescence (high school years) ovulation and cycles become more regular per individual. In late adolescence, you move out on your own and transition into the childbearing years. Also, perimenopause occurs before menopause, and while it can occur during the childbearing years, it has different characteristics.

Therefore, for the purposes of my discussions, I’m going to define the childbearing years as the time between the end of mid-adolescence and the onset of perimenopause. While it’s possible to become pregnant while in perimenopause, there are characteristics of childbearing years and perimenopause that I’d like to focus on separately. So I’m splitting them into separate posts.

Also, the late adolescent age group has different characteristics than earlier stages of adolescence. This is the time period when one becomes independent. One group, college students, have an entirely different set of circumstances than high school students. For instance, there may be Return to Learn (RTL) needs for both groups. However, for those in college, the student must advocate for herself. She may also be far from home geographically and have some isolation as a result. She may have a sports scholarship. There is also a greater risk of assault on campuses, unfortunately, which is another risk factor for concussion.

During this life phase, difficult recoveries might be more likely, as indicated in several studies by the University of Rochester. Women of childbearing age have been shown to have worse outcomes than pre-menarche and post-menopausal females. Researchers determined that a likely cause is that estrogen and progesterone have higher levels during the childbearing life phase. [1] [2]

Pregnancy and fetal development are also of high importance during this life phase. There may be issues with post-TBI hypopituitarism that affects not only the ability to carry a pregnancy, but the fetus specifically as well. Prolactin levels can also be affected, which means breast feeding could be impacted.

This age group is of tremendous importance, not only for each individual, but for fertility, pregnancy, and fetal development.

Basics

Age range	20 – 35
Age at which cycles become regular per individual	19 – 20 [3]
Average cycle duration	21 – 34 days [3]

Potential Issues

Hypothyroidism
Amenorrhea
Anovulation
Female Athlete Triad
PCOS
Luteal Phase Defect (LPD)
PTSD and suicide
Miscarriage

Progesterone Levels and the Luteal Phase

The menstrual cycle is normally regular at this stage in life. Estrogen and progesterone levels fluctuate throughout each cycle. Progesterone levels have significance, particularly in the luteal phase (LP). Progesterone levels are high during this time. A sudden drop in progesterone levels (the “withdrawal hypothesis”) following a TBI may be a cause of prolonged recovery. [2] Another study suggests that women who experience a traumatic event during the LP may be at risk of developing depression and PTSD. [4] For female veterans who have a concussion, this may be very important to review.

In January of this year, the Department of Veterans Affairs released an alarming study about suicide by young veterans. They found that suicide rates for veterans under the age of 30 increased significantly from 2009 – 2011, and were significantly higher than society in general. Rates increased 11% for females and 44% for males. [12] Female veterans that were victims of a sexual attack are more likely to report PTSD and anxiety. Nearly half the veterans who experienced an assault considered suicide. [18] If a female soldier experiences trauma during the LP and has depression and PTSD as a result, might this be a contributing factor to increases in suicide rates? We owe it to our veterans to review this more in-depth.

Pregnancy

During pregnancy, progesterone levels remain high.

Data shows that the average age that females had their first child increased from age 21 in 1970 to age 25 in 2006. [15] Later statistics reflect the same pattern through 2010. [16] When reviewing concussion for the childbearing years, I think it’s good to look at ages 25 – 29 closely in terms of development and potential impact. This as opposed to late adolescence, when there may still be some transition in play. In late adolescence, there may be additional uses for birth control pills. For instance, athletes may use birth control in a large part to manage their menstrual cycles.

Hypothyroidism and Pregnancy

Hypothyroidism is a possibility after a brain injury. Even mild instances of hypothyroidism can cause problems during pregnancy. [10]

Because thyroid hormones are crucial to fetal brain and nervous system development, uncontrolled hypothyroidism—especially during the first trimester—can affect the baby’s growth and brain development. [11]

Potential for Miscarriage

Given that a large number of people suffer a concussion due to automobile accidents, I think that this topic needs to be looked at further. There’s so much focus on sports that I think this important cause of concussion is overlooked. Make no mistake – the focus on sport is important and has resulted in much action and awareness. At this point in time, we need that focus. However, it’s not good to exclude other causes from the discussion. I think that hypothyroidism issues with pregnancy and fetal development are an excellent example of a reason to expand the scope of research.

With that in mind, here is some information.

Researchers at the University of Rochester recorded the source of injury for mild TBI emergency room visits over a period of time. The mean age of study participants was 30 years. For females, they found that motor vehicle crashes resulted in the highest number of injuries (277 of 643; 43.2%) and sport or cycling injuries accounted for a significantly lower number (97 of 643; 15.1%). Conversely, for males, motor vehicle crashes also accounted for the highest number of injuries yet had a much lower percentage (220 of 782; 28.1%) and sports or cycling were next highest cause (201 of 782; 25.7%). [2]

If a woman is pregnant and sustains a concussion in a motor vehicle accident, might that increase the risk for miscarriage? Progesterone levels are high during pregnancy. If there’s a sudden drop, as indicated in the study, does that pose a risk? I’ve also been reading that low progesterone can be a risk for miscarriage in pregnancy in general. If your progesterone level is already low or you’re on the cusp of having this issue, might a concussion tip the scale and result in miscarriage? However, I wonder if an acute withdrawal of progesterone as indicated in the withdrawal hypothesis may cause this to occur. There might not be a risk, but this study just came out. I think it should be looked at.

Review the Luteal Phase Defect (LPD) section later in this post as well. LPD can cause miscarriage.

College Students

The late adolescent age group has different characteristics than earlier stages of adolescence. This is the time period when one becomes independent. One option, of course, is pursuing further education.

College students who have a concussion have an entirely different set of circumstances than high school students. For instance, there may be Return to Learn needs for both groups. However, for those in college, the student must advocate for herself. She may also be far from home geographically and have some isolation as a result. She may have a sports scholarship. There is also a greater risk of assault on campuses, unfortunately, which is another risk factor for concussion.

Assault

When reviewing assault instances for college students, keep the following two items in mind. Both apply to a wider age range, not just college students. The University of Rochester study found that assault accounted for 6.1% of mild TBI injuries (30 of 643). [2] It doesn’t detail the type of assault. Also, a study found that 35% of a survey of women who were treated at emergency rooms for domestic violence – sexual assault possibly had a mild TBI and that there was a higher incidence of post-concussion syndrome. [19]

A White House report released in January identified an alarming statistic: 1 in 5 college students are sexually assaulted. Only 12% report what happened. Some students might develop eating disorders afterward. Additional issues might ensue that include impaired memory and delayed recall, among others. [18] These are important to note.

Eating disorders are one of the three aspects of the Female Athlete Triad. If you’re not getting the proper nutrition due to disordered eating (DE), it could affect the menstrual cycle and result in amenorrhea. The memory and recall items are reviewed in neuropsychological exams. So if you have an athlete who may have been sexually assaulted but has not reported it (or has reported it), I think you need to keep that in mind. Is there also a Triad issue or an assault response? Are cognitive issues found on a neuropsychological exam from the concussion or the assault? Or both? Might an assault have exacerbated such responses? From what I’ve read, DE is very serious and requires assistance by medical personnel. I would imagine that there are procedures for handling or asking about assault. For college students, I think the medical community should consider all of these possibilities when treating concussions to ensure there are no additional issues.

Sports and Birth Control

Females use birth control for more than prevention of pregnancy. For instance, athletes may use birth control in a large part to manage their menstrual cycles to try and optimize training and competition participation. Birth control is used to address amenorrhea and anovulation issues. While it has been used some for the Female Athlete Triad, it is strongly recommended to address the Triad through nutrition instead. Use of combination estrogen – progestin birth control pills can also worsen bone mineral density(BMD) issues, another of the three Triad issues. [23]

Luteal Phase Defect (LPD)

In a normal cycle, ovulation produces progesterone via the corpus luteum. One type of dysfunction with the menstrual cycle is Luteal Phase Defect (LPD). Due to inadequate pulse activity, the corpus luteum does not function normally, which affects progesterone levels. [4] With LPD, there’s a shortened luteal phase. The LP when a female has LPD is generally less than 10 days. [20] [21] [24] In normal cycles, the LP is 12 – 16 days.

LPD is something that can occur more often for athletes. A study that researched menstrual dysfunction for active women found that 27.1% of women in the study who exercised had LPD (13 of 48 women). [20] Anovulatory cycles were another issue.

LPD has been linked to miscarriage [24] although there’s also been discussion that LPD does not cause this issue [22]. I currently don’t have time to research this more fully. However, I think it’s important to review in more detail. Also, there’s good information about LPD in relation to menstrual cycles in exercising women. An excellent image to review that shows different hormone levels in regular cycles, shortened LP cycles due to LPD, and anovulatory cycles, is on page 500 in the study listed in footnote 23. It’s Figure 4. I’ve requested permission from the publisher to include it here, but haven’t heard back yet. Take a look at that (Figure 4); you can see the different levels very clearly. The entire study is worth reviewing and bookmarking, especially with regard to LPD.

A question I have is: with regard to female athletes in particular, might some already have LPD? If a female had a concussion and hypopituarism as a result, would that make it worse? If a person has LPD, progesterone levels will be low. If a concussee had LPD before the incident that caused the concussion, perhaps progesterone levels were already low. [2] Perhaps the positive benefits of progesterone with regard to concussion recovery will be limited for those with preexisting LPD.

The problems and cause of LPD can be traced back to issues with FSH levels and the pulse. If there’s an injury to the pituitary, FSH levels may be affected:

The causes of luteal phase defect can be traced to a few principle factors. First off, a luteal phase problem may have its root in the first half of the cycle. That is to say, for the corpus luteum to function properly, it must develop and fully mature in its earlier incarnation as an “ovarian follicle”. Maturation of the ovarian follicle requires adequate follicular development brought about by another reproductive hormone – follicle stimulating hormone, or FSH. Low levels of FSH (or stress on the ovarian follicle) can prevent its full maturation; thus, during the luteal phase, this may lead to a corpus luteum that is unable to perform its proper function in producing progesterone at adequate or sustained levels. However, failure of the corpus luteum may also occur even in the case of a healthy, fully-developed follicle. In either situation, the corpus luteum prematurely falters or fails to deliver adequate levels of progesterone. [5]

Triad

There are very important and special considerations regarding the Female Athlete Triad. Instead of repeating information here, please review this post: Female Athlete Triad and Concussion Recovery.

Manipulating Birth Control

In the course of my research, I came across this interesting tidbit. Two immediate questions came to mind. First, do college athletes do this to manipulate their cycles so they don’t have a period for a competition? Second, how might this affect different hormone levels (if indeed it does)?

“University of Oregon researchers found what they consider to be a surprisingly high number of female college students who “purposefully deviate from the prescribed use of their combined hormone contraceptives to exert elective control of their scheduled bleeding.” [6][7]

It may be that athletes do not participate in this practice if they are using birth control to try and keep cycles normal (for instance, in the case of the female athlete triad). This is identified in the study as one factor for those who don’t purposefully change their cycle.

I don’t know what significance, if any, this has with regard to concussion. However, I think it’s interesting and something to keep in mind as you look into hormones and concussions. Clearly, there is some correlation between hormone levels during the menstrual cycle. If a concussee is manipulating her period in this manner, how might that impact recovery?

ACL Injuries

Because females have such high rates of ACL injuries, I wanted to mention this here as an FYI. ACL injuries most often occur at ovulation, when estrogen is at its highest. [9] If you’re thinking of taking an estrogen-based birth control pill but are very active, this may be one consideration for you.

Here’s another interesting development. I haven’t time to look at it more in detail, but am letting you know about it. A recent study found that neurocognitive scores were different when getting an ACL. [25]

[1] Wunderle K, Hoeger K, Wasserman E, Bazarian J “Menstrual Phase as Predictor of Outcome After Mild Traumatic Brain Injury in Women” Journal of Head Trauma Rehabilitation

[2] Bazarian J, Blyth B, Mookerjee S, He H, McDermott M “Sex Differences in Outcome after Mild Traumatic Brain Injury” Journal of Neurotrauma 27:527-539 (March 2010)

[3] Menstruation in Girls and Adolescents: Using the Menstrual Cycle as a Vital Sign. Pediatrics 2006;118;2245

[4] Hormone Levels May Provide Key to Understanding Psychological Disorders in Women sciencedaily.com May 24, 2013

[5] What is a Luteal Phase Defect? Early-pregnancy-tests.com

[6] Women Altering Menstrual Cycles in Large Numbers sciencedaily.com May 9, 2013

[7] Lakehomer H, Kaplan P, Wozniak D, Minson C “Characteristics of scheduled bleeding manipulation with combined hormonal contraception in university students ” Contraception Volume 88, Issue 3 , Pages 426-430, September 2013

[8] American Academy of Pediatrics Stages of Adolescence healthychildren.org Updated: August 2013

[9] Reference removed 8.18.21: link no longer active

[10] Hypothyroidism During Pregnancy medicinenet.com Reviewed January 9, 2014

[11] National Institutes of Health Thyroid Disease and Pregnancy nih.gov

[12] Denver Nicks Report: Suicide Rates Soar Among Young Vets Time January 10, 2014

[13] Link Between Car Crashes, Adverse Pregnancy Outcomes sciencedirect.com October 8, 2013

[14] Reference removed 8.18.21: link no longer active