Irregular menstrual cycle patterns – stress perspective

Irregular menstrual cycle

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Last week I wrote about what a normal period should look and feel like.

This post is all about irregular menstrual cycle patterns, and what they might mean from a stress physiology perspective.

Tracking will help you identify what is happening with your menstrual cycle, but interpretation of those patterns requires an understanding of what is considered normal vs abnormal.

In this post we will cover irregular periods. Both long cycles and short cycles are types of irregular periods. Lack of periods, known as amenorrhea, will also be discussed. There are many reasons for an irregular cycle. Stress being a common one, especially for women 45 years of age or younger. However, certain medical conditions, like thyroid disease, celiac disease, PCOS, and others should be ruled out first. When no medical diagnosis can be found, stress may be the cause. But how exactly does stress lead to irregular periods?

Recap – Menstrual cycle irregularity: no periods; late periods and early periods (includes long cycles and short cycles, respectively)

I want to emphasize that this post is not meant to replace medical advice from a doctor or other healthcare provider. There are certainly times when it is strongly advised to see your doctor. For example:

  1. No periods
  2. Cycles that are shorter than 21 days or longer than 35 days
  3. Bleeding for more than seven days
  4. Losing more than 80 mL of menstrual fluid in one period
  5. Period pain so bad that you cannot do your normal activities
  6. Pain between periods, especially if it is severe
  7. Bad-smelling vaginal discharge
  8. Bleeding between periods that is not ovulation spotting

Excerpt From: Briden, Lara. “Period Repair Manual: Natural Treatment for Better Hormones and Better Periods.”

No periods at all?

First off, if you are aged 16 or older and have never had a period, then please see your doctor. That is known as primary amenorrhea (absence of periods). If you used to have them but now they’ve stopped, then that’s called secondary amenorrhea. That’s what we’ll be focusing on here.

Causes may include: pregnancy, perimenopause, stress, and other medical conditions.

PREGNANCY

This might seem obvious, but you could be pregnant. Don’t rule this possibility out until you’ve done a pregnancy test, even if it’s been several months since your last period. Light bleeding (as in, strangely light period) is common in early pregnancy as well, just FYI. If in doubt, test test test.

PERIMENOPAUSE

The beginning of menopause is a transition period, so things are changing. It could be the reason for your lack of periods; however, it’s unlikely if you are 40 years old or younger. Premature menopause is possible though, and sometimes looking at family history can help. Ask your mother, aunts, older sisters, etc, when their periods stopped. Your doctor can also easily check by running a blood test called FSH, which tests levels of follicle stimulating hormone.

STRESSED OR SICK?

Stress comes in many forms – physical, emotional, under eating, exams, trauma, surgery, a really bad cold, you name it. Your reactions to stress are controlled by a complex set of feedback interactions among the hypothalamus, the pituitary gland, and the adrenals (known as the HPA axis). External stressors are translated into messages which influence the feedback loops of the HPA axis. Meaning, if your brain perceives a particular stressor to be threatening, then it’s not a good time to make a baby. This executive decision is made by your hypothalamus, the part of your brain that acts like a command centre for your hormones. It’s not very discerning. Basically, stress is stress. At a certain threshold (and everyone is different), repeating or chronic stress can stop your period. But this is usually temporarily, until the situation improves.

Take under eating as an example. If you aren’t consuming enough food for yourself then you probably don’t have the resources to support another life inside of you. From your body’s perspective, health is synonymous with reproduction. Even if you don’t want a baby, this stressor will trigger a “starvation” response by the hypothalamus to suppress reproduction. Interestingly, this can happen with low carbohydrate diets too, even if you are consuming enough calories. Everyone is different, so saying “low carb” isn’t that helpful, but too few carbs for you can trigger the starvation response in your hypothalamus. Some women need a lot of carbohydrate to ovulate, while others need less. Definitely something to consider if you’ve made some drastic dietary changes recently.

If this situation becomes chronic (6 months or longer), it is called hypothalamic amenorrhea (HA). Other causes must be ruled out first before this diagnosis is given. Again, this is just your hypothalamus telling you that it’s not a good time to make a baby. Maybe you don’t have the resources or it’s too dangerous to do so (remember that the hypothalamus can not discern between life threatening stressors and other types of stressors).

MEDICAL CONDITIONS

Lack of periods can also be caused by certain medical conditions, like thyroid disease, celiac disease, PCOS, and others. Your doctor should rule out these other causes. When no medical diagnosis can be found, lack of a menstrual period for more than six months is diagnosed as hypothalamic amenorrhea (HA).

Irregular periods

Are your periods late? If your periods come later than every 35 days then that’s considered a long cycle, which is a type of irregular period. Either you didn’t ovulate or your follicular phase (the first half of your cycle) is very long. One of the most common causes is PCOS. For people older than 45 years, it is important to rule out thyroid disease, PCOS or perimenopause.

Causes may include: anovulatory cycles, long follicular phase

External stressors like illness or under eating could be the cause for both anovulatory cycles and a long follicular phase.

1. ANOVULATORY CYCLES

This is a cycle where you do not ovulate. It’s normal for this to occur occasionally. If it’s happening regularly, then you should talk to your doctor about PCOS. If that’s been ruled out, stress could be the cause. Stress disrupts the communication between your hypothalamus and anterior pituitary, which affects the release of hormones that stimulate the ovaries to produce estrogen and progesterone. “A disruption in the messages between the hypothalamus (which produces gonadotropin- releasing hormones) and the anterior pituitary (which releases FSH and LH, follicle-stimulating and luteinizing hormones) brings about a mistiming of the release of these hormones and a subsequent lack of ovulation and/or estrogen and progesterone production by the ovaries. The timing of the release of these pituitary hormones, as well as of estrogen and progesterone, is what determines a normal, regular menstrual cycle. This timing can be adversely affected by stress, and by the same token, the timing can be improved by stress reduction” (Women’s Encyclopedia of Natural Medicine, Tori Hudson, 2008).

The timing of the release of pituitary hormones (LH and FSH), as well as ovarian hormones (estradiol and progesterone), is what determines a normal, regular menstrual cycle.

Figure explanation: The communication between the brain and ovaries is known as the hypothalamic–pituitary–gonadal axis (HPG axis). Two glands are involved, the hypothalamus and the pituitary. GnRH is a hormone from the hypothalamus. It tells the pituitary to release two hormones, LH and FSH, which speak to the ovaries to produce progesterone and estradiol. The hypothalamic-pituitary-adrenal (HPA) and the hypothalamic-pituitary-gonadal (HPG) axes work together. Activation of one affects the function of the other and vice versa.

Source: McCance, K. L., & Huether, S. E. (2018). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). St. Louis, Missouri. Elsevier Health Sciences. 1720 pages.

But how exactly does stress intercept the communication between the brain and the ovaries? Three words: gonadotropin-releasing hormone (GnRH). In the hypothalamus, the release of GnRH stimulates the gonadotropin production of FSH and LH. The constant and pulsatile release of GnRH is critical to the timing of the menstrual cycle.“…activation of the stress axis, especially activation that is repeating or chronic, has an inhibitory effect upon gonadal hormone secretion. For example, stress and stress hormones inhibit the release of gonadotropin releasing hormone from the hypothalamus, and glucocorticoids inhibit the release of luteinizing hormone from the pituitary and E2 and progesterone secretion by the ovary…” (Toufexis, D., Rivarola, M. A., Lara, H., & Viau, V. (2014). Stress and the reproductive axis. Journal of neuroendocrinology, 26(9), 573–586. doi:10.1111/jne.12179).

Basically, stress inhibits hormone secretion, which has a profound effect on human reproductive health and emotional well-being. Going back to stress as a cause of anovulatory cycles, it makes sense that a hormonally mediated event (ovulation) is suppressed when its hormonal trigger (LH surge) is inhibited.

If your doctor has ruled out all potential medical causes for an irregular cycle, then you should not be disappointed. A full workup and thorough assessment is not wasted effort. If everything comes back “normal”, then that is a great outcome.

Please be aware that you can’t test for HPA or HPG axis dysfunction, per se. At this stage, there is no reliable way to assess it; however, your signs and symptoms are a good place to start. Sometimes certain tests can help, such as salivary cortisol levels or serum DHEAs levels. Your naturopathic doctor may run these, along with others. But these tests should be evaluated in the context of your symptoms.

2. LONG FOLLICULAR PHASE

The menstrual cycle consists of two phases: the follicular/proliferative phase (postmenstrual) followed by the luteal/secretory phase (premenstrual).

Source: Hall, J.E. 2019. Yen and Jaffe’s Reproductive Endocrinology, Eighth Edition. Physiology, Pathophysiology, and Clinical Management; Chapter 7 – Neuroendocrine Control of the Menstrual Cycle, Pages 149-166.e5. Available online 22 February 2018.

The follicular phase is the period of recruitment of multiple follicles (sacs within your ovaries that contain the eggs) and emergence and growth of one dominant follicle. Around day 7, all of the follicles stop growing and begin to degenerate except for one. During this phase, rising levels of estradiol are associated with thickening (that’s why it is also called the proliferative phase) of the endometrium (the lining of the uterus). Those follicles are secreting estradiol into the blood, telling the anterior pituitary to secrete LH. Eventually, the one dominant follicle secretes a large amount of estrogen into the blood stream, which tells the pituitary gland to release a huge surge of LH into the blood stream. In a 28-day menstrual cycle, this is occurring around day 12. LH spikes in the middle of the cycle (between the follicular and luteal phase). That occurs right before ovulation. This is all normal physiology.

Now imagine what happens with chronic stress: your HPA axis has been activated, stress hormones inhibit the release of gonadotropin releasing hormone from the hypothalamus, and the release of luteinizing hormone from the pituitary and estradiol and progesterone secretion by the ovary. Hormones are inhibited at three levels: hypothalamus, pituitary and ovaries.

From our discussion of normal menstrual physiology we know that a surge in both FSH and LH levels is required for final follicular growth and ovulation. With all that hormonal inhibition going on, the hormonal surges aren’t happening. Follicle growth is slowed, therefore, hormones aren’t reaching peak levels, and the follicular phase drags on. Ovulation likely won’t happen (anovulatory cycle), but eventually your endometrium will start to degenerate (menstruation begins). You can see why this whole process in the follicular phase would take longer without the appropriate hormonal signals. If you’re younger than 45, a long follicular phase could be stress or PCOS. If you’re older than 45, a long follicular phase could be thyroid disease, PCOS, or the final transition to menopause.

Are your periods early? Like long cycles, short cycles are a type of irregular period. As an adult, a healthy menstrual cycle is anywhere between 21 to 35 days, with 28 days being the average. Your period should come no sooner than 21 days. A healthy menstrual cycle between 21 to 45 days is considered normal for a teenager. Teenagers have longer cycles because it can take up to 12 twelve years to develop a mature menstrual cycle.

Causes may include: an anovulatory cycle, a short follicular phase, or a short luteal phase

1. SHORT FOLLICULAR PHASE

So far, we’ve covered how stress induced hormonal changes can cause a variety of menstrual cycle disturbances, like anovulatory cycles, irregular periods, and even amenorrhea. Our discussion will continue to focus on stress as a cause, especially for a short luteal phase; however, a short follicular phase is different. It is most common during perimenopause. This is beyond the scope of this post, but since you are pretty much hormonal experts by now, I’ll say this. During perimenopause your pituitary starts making more follicle stimulating hormone (FSH). As you get older, your ovaries become less response to FSH, so your brain makes more to compensate for this lack of response. Higher FSH speeds up all of the hormonal surges that eventually trigger ovulation, which effectively ends your follicular face. Voila, short follicular phase.

2. SHORT LUTEAL PHASE

A short luteal/secretory (premenstrual) phase can be caused by many of the same things that cause lack of periods, stress being the most common.

The luteal phase, which begins on the day after the LH surge, is characterized by the formation of the corpus luteum (yellow circle with bursting purple follicle in image above). The corpus luteum is a hormone secreting structure. It secretes progesterone to prime the uterus for implantation (secretory phase). In the absence of pregnancy, the corpus luteum declines (yellow fluffy clouds in image), therefore hormone secretion declines, resulting in the endometrium losing its blood supply. It is then shed, which is the beginning of menstruation.

The luteal phase, which begins on the day after the LH surge, is characterized by the formation of the corpus luteum (yellow circle with bursting purple follicle). The corpus luteum is a hormone secreting structure. It secretes progesterone to prime the uterus for implantation (secretory phase). In the absence of pregnancy, the corpus luteum declines (yellow fluffy clouds in image), therefore hormone secretion declines, resulting in the endometrium losing its blood supply. It is then shed, which is the beginning of menstruation.

With a healthy corpus luteum, you can expect 11-16 days between ovulation and the first day of your period. Unless you are pregnant, your luteal phase can never be more than 16 days. That’s because your corpus luteum can survive only 10 to 16 days, which is what defines your luteal phase. But if it’s fewer than 11 days, then you’ve had a short luteal phase.

The biggest issue with a short luteal phase is that it results in low progesterone production. A healthy period depends on having optimal progesterone levels. By healthy period I mean it arrives on time, with no PMS symptoms in the luteal phase, no premenstrual bleeding or spotting, and your uterine lining is in good shape (well-formed and not too thick or inflamed, and fairly easy to shed).

You’re probably wondering how stress can shorten the luteal phase. Not surprisingly, it’s all about hormone balance – again. When hormones are balanced, all four phases of the menstrual cycle are normal: menstruation, the follicular phase, ovulation and the luteal phase. In the hypothalamus, the release of GnRH stimulates the gonadotropin production of FSH and LH. The constant and pulsatile release of GnRH is critical to the timing of the menstrual cycle. You can see this illustrated in the image above (green bar with black arrows). The black arrows indicate the pulse frequency of GnRH.

Gonadotropin- releasing hormone is produced by the hypothalamus, aka the command centre for your hormones. Stress disrupts the pulsatile release of GnRH (due to stress hormone inhibition), which causes a downstream inhibitory effect on hormones released from the anterior pituitary and the ovaries. The consequence is a mistiming of the release of FSH, LH, a lack of ovulation, and/or a lack of estradiol and progesterone production.

A number of factors increase the chance of irregular menstrual cycle patterns. This post focused on stress-induced hormonal changes. The two main hormones that are said to impact menstruation are estrogen and progesterone. These hormones regulate the cycle. Now you understand why and how they do that.

The underlying cause for their imbalance is upstream, at the brain level. That is where stress is perceived and where stress triggers a cascade of hormonal responses via the HPA axis and its interaction with the HPG axis.

McCance, K. L., & Huether, S. E. (2018). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). St. Louis, Missouri. Elsevier Health Sciences. 1720 pages.