Periods Changing? The Brain-Ovary Connection
Hypothalamic Amenorrhea: A Common Cause For Cycle Changes
Written by Dr. Fiona Callender, ND
Has your period been changing? I often get my patients to start tracking their cycle when they first come in to my office - whether that’s with their calendar or using a period tracking app - to start to understand what their normal is. If your cycle has been shortening or you’ve skipped a few periods, that warrants an investigation.
One of the most common causes of period changes/skipped periods is related to functional hypothalamic amenorrhea (FHA). FHA is caused by changes in hormone signalling from the brain, usually due to reduced energy availability or high stress. Hypothalamic amenorrhea is responsible for about 20-35% of cases of skipped periods in young women. These numbers are likely higher in teenagers!
What’s actually happening?
If we are in a situation where energy is scarce, or perceived stress is high, the body minimizes it’s energy expenditure by limiting our “less important” functions - those that aren’t needed to survive. Menstruation/reproduction is one of those functions! If we are exercising a lot and not supporting our body with enough food (energy), our energy availability for essential bodily functions might not be enough. Our brain responds by slowing the release of the hormone GnRH from the brain, which then reduces the release of FSH and LH from our pituitary gland. This ultimately leads to ovarian follicles not developing and low levels of some of our other hormones - including estrogen. For some, this looks like shorter cycles or skipping cycles. For others, they may lose their periods completely.
It’s not always as obvious or intentional as you might think. You don’t have to be actively restricting calories or exercising to the extremes to have your period impacted by low energy availability. Even relatively small energy deficits can lead to changes in the frequency of hormonal pulses from the brain. For teenagers, the sensitivity to these changes is even higher! Even a few hundred calories in deficit (which may easily be accidental) can lead to changes in their cycle.
The same goes for “stress”. Everyone’s body perceives stress differently depending on their history and genetics. There is evidence that several forms of psychological stress can impact menstrual cycles by either lengthening or shortening them, or even making them heavier. Academic or job related stress, COVID-19 related stress, abuse or relational stress etc. can all impact menstrual cycles. Many people who land in my office don’t necessarily feel stressed, but their body might be telling them otherwise.
Identifying the cause of your cycle changing can help us support you better. We know that there are other conditions or situations that can also cause changes to your cycle - so we want to rule those out too! Some other causes include: PCOS, thyroid conditions, elevated prolactin, perimenopause/menopause, and pregnancy.
Why we care
For many patients - especially young and active ones - they don’t mind skipping their period! But getting a regular period is more important than you might think. When we don’t signal the ovaries to develop follicles, we end up in a low estrogen state. This can lead to health problems down the road, including:
Low bone mineral density: There’s been research suggesting that for young women, even having 6 months in a low-estrogen state can result in a bone mineral density level similar to that of a woman in her early 50s. This is really important for long-term bone health, injury prevention, and quality of life as you age.
Thyroid issues: Changes in thyroid function might be your body’s attempt to regulate your basal metabolic rate in response to low energy availability. It’s often fairly subtle on lab work, but there may be changes in the way our body manages our thyroid hormones.
Cardiovascular effects: Estrogen deficiency can negatively impact heart health in young women. This puts you at higher risk of cardiovascular disease down the road.
Fertility challenges: Reduced ovulatory cycles and changes to the development of the endometrium make pregnancy more challenging. There is also an increased risk of miscarriage in these scenarios. Thankfully, these are thought to be reversible when the cause of FHA is addressed.
Understanding your cycle and getting support
Diagnosis and support requires an assessment. We discuss your health history and get an understanding of your menstrual cycle history, your nutritional habits/needs, your exercise history, your stress and routine, your sleep, and more. We also run some blood work - whether that’s through me or through your family physician or nurse practitioner - to help us understand the cause of your cycle changes. Treatment and support are tailored to you and your specific situation and goals.
If some of this resonated with you or you want to start understanding the changes in your menstrual cycle, you can book a meet and greet appointment with me to discuss whether I might be a good fit for your needs.