By: Jessica Long, MS, RD, LDN

 

Menstruation, A Vital Conversation

When you hear the word menstruation or period, what words come to mind? Maybe things like flow, cramping, spotting, inconvenient, or unpredictable. I’d like to add an additional word to the menstrual cycle vocabulary: vital. 

You are probably familiar with the four vital signs taken at any routine doctor’s appointment: blood pressure, heart rate, respiratory rate, and temperature. What if we are missing a big piece of our health puzzle? What if I told you that there was a fifth vital sign, one relevant to roughly one quarter of the global population,1 and that to ignore it not only gives an incomplete picture of health but can also have significant health consequences?

I’m talking, of course, about the menstrual cycle. Although the American College of Gynecologists (ACOG) recognized the menstrual cycle as a vital sign back in 2015, the pervasive dismissiveness about irregular periods remains nearly a decade later.2 

An Illuminating Illustration

I recently had a client attend a physical exam at her doctor’s office. Upon arrival, her blood pressure was lower than usual for her. The medical provider was concerned (and rightly so). Later on in her appointment, my client vocalized that her period had been absent for three full cycles. In striking contrast to the doctor’s reaction to her low blood pressure, in this case she was told that this was normal and not to worry about it. 

Fortunately, her low blood pressure was a simple case of inadequate hydration, and a bottle of water brought her blood pressure back up to normal. Unfortunately, her period concerns were dismissed… a vital sign ignored. Thankfully, through our work together, she knew this was not the correct response, and we continued the necessary work of recovering her lost period by focusing on consistent and adequate nourishment. 

Period Education

In order to begin to envision a period as a mirror of health, it’s necessary to understand exactly what’s going on in the body throughout a menstrual cycle. 

Colorful chart illustration the menstrual cycle and homonal changes

The first half of the cycle is called the Follicular phase. It begins with one’s menstrual period and ends with ovulation. 

  • The hypothalamus produces Gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release FSH and LH. 
  • Follicle stimulating hormone (FSH) stimulates ovarian follicles to mature in preparation for ovulation. 
  • Luteinizing hormone (LH) triggers ovulation. 
  • Estrogen is the dominant hormone of the follicular phase. Its role is to stimulate growth of the follicle, thicken the uterine lining, and trigger LH.

The second half of the cycle is called the Luteal phase. It begins after ovulation and ends the day before the next menstrual period.

  • Progesterone prepares the uterus for implantation. It plays a key role in maintaining the health and integrity of the uterine lining. 

Why Regularity Matters

Regular periods are a critical sign of health for menstruating people! Here are just a few of many reasons:

  • An imbalance between estrogen and progesterone, often seen in those with irregular cycles, can increase the risk of certain cancers.3
  • Adequate estrogen supports bone health. Low estrogen accelerates bone resorption, which means loss of bone density.4 Low estrogen is seen in those with amenorrhea (absent periods). 
  • Irregular ovulation is correlated with an increased risk of hypertension, diabetes, and cardiovascular disease.5-7 
  • Research suggests that ovulating regularly is protective against atherosclerosis.8  

Periods: What Is Normal?

The normal length for one complete menstrual cycle, meaning from the start of one period to the day before the next, is between 21-35 days.9 Periods typically last 3-7 days with the first few days having the heaviest bleeding.9 Ovulation does not always happen exactly halfway through the cycle, but cycle day 15 is the most common ovulation day.10 It is considered normal to ovulate as early as cycle day 11 or as late as cycle day 21.11 Mild period cramping is common and considered normal, but extremely painful, debilitating cramping is not normal and should be investigated further.12

How Nutrition Affects Normal Menstruation

When the body is not given enough nourishment, whether that be in the context of an eating disorder, excessive exercise, or food insecurity, it temporarily shuts down systems that aren’t absolutely necessary for survival in favor of maintaining more essential functions. The reproductive system is a prime example of this phenomenon. From a biological perspective, getting pregnant and maintaining a pregnancy require a significant amount of energy. During periods of energy deprivation – whether intentional or not – it makes logical sense for the body to prevent this process by pausing ovulation, thereby pausing periods. Sporadic or inadequate nourishment also alters hormone signaling and decreases secretion of the hormones needed to trigger ovulation.13 The next article in our series on periods will be dedicated to this condition, known as hypothalamic amenorrhea. 

Whenever someone (be it yourself, a friend, a loved one, or a patient!) begins to have “wonky” cycles, asking the question, “Have there been any changes in eating or exercise habits?” is a helpful place to start. Sometimes, the eating or exercise changes are subtle and, given that diet culture is so pervasive, may even be praised by others. Thankfully, by focusing on adequate nourishment and moderating excessive movement, the body can begin to trust that it is safe to menstruate again.14

Cycle Tracking

I am a huge proponent of cycle tracking to help recognize menstrual cycle changes. Tracking can look different from person to person depending on what their goals are, and how in depth they choose to track. I love using Apps like Ovia, Pregmate, Clue, or PreMom for tracking period length and symptoms, cervical mucus patterns, and other changes over the course of the cycle.

We’re Here to Help

Are you concerned that your relationship with food and exercise is impacting your cycle? Are you interested in nutritional support for regular periods or fertility? Lutz, Alexander & Associates Nutrition Therapy is a team of experienced Registered Dietitians specializing in eating disorders, disordered eating in Raleigh, Durham, Chapel Hill, and Cary, NC, and we’d love to help! Contact us today.

 

Citations: 

  1. UNICEF. FAST FACTS: Nine things you didn’t know about menstruation. Published May 25, 2018. Accessed June 9, 2025. https://www.unicef.org/press-releases/fast-facts-nine-things-you-didnt-know-about-menstruation
  2. American College of Obstetricians and Gynecologists. Committee Opinion No. 651: Menstruation in girls and adolescents: using the menstrual cycle as a vital sign. Obstet Gynecol. 2015;126(6):e143–e146. doi:10.1097/AOG.0000000000001215
  3. Harvard T.H. Chan School of Public Health. Connecting the dots between irregular periods, polycystic ovary syndrome and endometrial cancer risk. Apple Women’s Health Study. Published August 2023. Accessed June 9, 2025. https://www.hsph.harvard.edu/applewomenshealthstudy/updates/periods-pcos-endometrial-cancer-risk-data/
  4. Endocrine Society. Menopause and bone loss. Published January 24, 2022. Accessed June 9, 2025. https://www.endocrine.org/patient-engagement/endocrine-library/menopause-and-bone-loss
  5. Lo ACQ, Lo CCW, Oliver-Williams C. Cardiovascular disease risk in women with hyperandrogenism, oligomenorrhea/menstrual irregularity or polycystic ovaries (components of polycystic ovary syndrome): a systematic review and meta-analysis. Eur Heart J Open. 2023;3(4):oead061. Published 2023 Jun 9. doi:10.1093/ehjopen/oead061
  6. Wang Z, Mahalingaiah S. Irregular periods linked with increased risk for cardiometabolic conditions. Harvard T.H. Chan School of Public Health. Published May 23, 2024. Accessed June 9, 2025. https://hsph.harvard.edu/news/irregular-periods-linked-with-increased-risk-for-cardiometabolic-conditions/
  7. Okoth K, Smith WP, Thomas GN, Nirantharakumar K, Adderley NJ. The association between menstrual cycle characteristics and cardiometabolic outcomes in later life: a retrospective matched cohort study of 704,743 women from the UK. BMC Med. 2023;21(1):104. Published 2023 Mar 20. doi:10.1186/s12916-023-02794-x
  8. Kaplan JR, Manuck SB. Premenopausal Reproductive Health Modulates Future Cardiovascular Risk – Comparative Evidence from Monkeys and Women. Yale J Biol Med. 2017;90(3):499-507. Published 2017 Sep 25.
  9. Cleveland Clinic. Menstrual cycle. Updated January 20, 2025. Accessed June 9, 2025. https://my.clevelandclinic.org/health/articles/10132-menstrual-cycle
  10. Soumpasis I, Grace B, Johnson S. Real-life insights on menstrual cycles and ovulation using big data. Hum Reprod Open. 2020;2020(2):hoaa011. doi:10.1093/hropen/hoaa011
  11. Leonard J. When am I most fertile? How to calculate your ovulation cycle. Medical News Today. Updated June 21, 2024. Accessed June 9, 2025. https://www.medicalnewstoday.com/articles/322951
  12. Simpson KM. Period pain: could it be endometriosis? Johns Hopkins Medicine. Published May 23, 2024. Accessed June 9, 2025. https://www.hopkinsmedicine.org/health/wellness-and-prevention/period-pain-could-it-be-endometriosis
  13. Iwasa T, Minato S, Imaizumi J, et al. Effects of low energy availability on female reproductive function. Reprod Med Biol. 2021;21(1):e12414. Published 2021 Sep 20. doi:10.1002/rmb2.12414
  14. Decker E, Hill K, Cohen G. How to Get Your Period Back in Eating Disorder Recovery. Equip Health. Published October 11, 2023. Updated May 8, 2025. Accessed June 9, 2025. https://equip.health/articles/treatment-and-recovery/amenorrhea-and-eating-disorders