Menstrual Cycle Health: What’s the Latest Research?
As new research emerges, the menstrual cycle’s impact on human health is becoming clearer.
Complete the form below to unlock access to ALL audio articles.
Dating back to ancient Greek culture, where the word “menstruation” is derived from the Latin and Greek word for moon – mene, the complexity of the menstrual cycle, and its impact on women’s health, has captivated researchers for centuries.
Characterized by its cyclical rise and fall of the female sex hormones, the menstrual cycle typically spans across an average of 28 days, split into 4 phases:
- Menstruation: The uterine lining sheds, triggered by a decrease in estrogen and progesterone levels.
- Follicular phase: The pituitary gland releases follicle-stimulating hormone (FSH), prompting the maturation of ovarian follicles. These follicles, in turn, produce estrogen, initiating the thickening of the uterine lining in preparation for potential pregnancy.
- Ovulation: There is a surge in luteinizing hormone (LH) that triggers the release of a mature egg from the ovary.
- Luteal phase: The ruptured follicle transforms into the corpus luteum, secreting progesterone to maintain the uterine lining in anticipation of implantation.
This delicate interplay of hormones governs the rhythm of the menstrual cycle, influencing not only reproductive processes but also broader aspects of health and well-being. As new research emerges, the menstrual cycle’s impact on human health is becoming clearer.
How does the menstrual cycle impact the brain?
In a recent study, published in Nature Mental Health, researchers investigated the impact of hormonal fluctuations on brain structure during the menstrual cycle.
"In general, the female brain is still massively understudied in cognitive neuroscience. Even though sex steroid hormones are powerful modulators of learning and memory, less than 0.5% of the neuroimaging literature considers hormonal transition phases, such as the menstrual cycle, the influence of hormonal contraceptives, pregnancy and menopause,” said corresponding author Dr. Julia Sacher, a professor in the Department of Neurology at the Max Planck Institute.
The study analyzed blood samples from 27 female participants to measure hormone levels and utilized ultra-high field 7 Tesla MRI to capture brain subregions at various menstrual cycle phases.
They found that specific areas of the medial temporal lobe expanded in sync with changes in estradiol and progesterone levels, crucial for episodic memory and spatial cognition. These changes were not apparent when studying the hippocampus as a whole, highlighting a potential limitation in traditional studies.
This research suggests that the female brain undergoes structural remodeling in response to hormonal fluctuations, offering insights into memory and mood disorders.
The menstrual cycle is driven by a circadian clock
Researchers at the University of Lyon investigated the internal mechanisms governing the menstrual cycle in a study published in Science Advances. Previous research suggested that endogenous factors like circadian rhythm might play a role. The study also examined the effects of external influences such as the lunar cycle's perceived connection to female fertility.
Analyzing data from over 3,000 women across Europe and North America, researchers found evidence suggesting that a clock-like mechanism is driving the ovulatory cycle. Cycles occasionally "jumped" forward to correct synchrony disruptions, similar to circadian clocks.
Although a weak link to the lunar calendar was observed, the authors suggest that lifestyle factors like the sleep-wake cycle may play a more significant role than lunar influence.
These findings open avenues for personalized medicine, with potential applications in treating ovulation disorders using chronobiological approaches.
“As one of the potential approaches, chronotherapy and/or bright light therapy could be tested in clinical trials to test their effect on the menstrual cycle and fertility,” the authors concluded.
Menstrual cycles are starting earlier in younger generations
A recent study from Harvard University, published in JAMA Network Open, explored the trends in the timing of girls' first menstrual periods, known as menarche, and its implications for women's health across generations.
Utilizing data from the Apple Women’s Health Study, which enrolled over 71,000 participants between November 2018 and March 2023, researchers investigated the age at menarche and the factors influencing it. A decrease was observed in the average age at menarche over the last five decades, with early and very early menarche rates almost doubling in younger age brackets. The study also revealed disparities among racial minorities and low socioeconomic groups, with higher rates of early menarche.
While BMI was identified as a contributing factor, explaining 46% of the temporal trends, other environmental and contextual factors were suggested to play significant roles. These findings underscore the urgent need for more investment in menstrual health research to address the growing health concerns associated with early menarche, particularly among disadvantaged populations.
Women are more likely to be injured in the luteal phase
A recent study identified a link between menstrual cycle phases and injury risk in female athletes. Published in Medicine & Science in Sports & Exercise, the research from UCL and the University of Bath investigated the potential impact of the menstrual cycle on injury risk among elite female footballers in the Women's Super League (WSL). Recognizing the menstrual cycle's systemic effects, which can induce physiological and psychological changes, the study aimed to monitor injury risk across different menstrual cycle phases.
Tracking 26 players across three seasons, they found injury risk was elevated during the pre-menstrual and early-mid luteal phases, with players six times more likely to experience muscle injuries during the former and five times more likely during the latter, compared to the menstrual phase.
The findings underscore the importance of reevaluating athlete support strategies and conducting further research to address the sex data gap in sports science, ensuring better player-centered support in elite women's football.
Women experience increased mental agility during menstruation
With recent research highlighting the impact of fluctuating hormone levels on variations in musculoskeletal injury risk among female athletes, a study from University College London and the Institute of Sport, Exercise & Health (ISEH) explored how mental cognition may play a role. Published in Neuropsychologia, researchers looked at how the menstrual cycle influences sport-related mental cognition.
“Research suggests that female athletes are more likely to sustain certain types of sports injuries during the luteal phase and the assumption has been that this is due to biomechanical changes as a result of hormonal variation. But I wasn’t convinced that physical changes alone could explain this association,” said Dr. Flaminia Ronca, associate professor at UCL Division of Surgery and Interventional Science and ISEH, and first author of the study.
Collecting reaction time and error data from 241 participants, including menstruating females and those on contraception, the team conducted sport-related cognition tests simulating mental processes used in team sports like soccer. Surprisingly, participants performed better during menstruation, exhibiting faster reaction times and fewer errors. However, reaction times were slower during the luteal phase, potentially impacting injury risk.
These findings challenge common assumptions about female athletic performance during different menstrual cycle phases and emphasize the importance of understanding how brain and body changes affect performance.
Enhancing women’s health
As research progresses, understanding the menstrual cycle's multifaceted impact is key to enhancing women's health and athletic performance. Navigating the intricacies of hormonal dynamics and cognitive function during the menstrual cycle holds promise for personalized interventions and improved well-being among women athletes.
References:
1. Ronca F, Blodgett JM, Bruinvels G, et al. Attentional, anticipatory and spatial cognition fluctuate throughout the menstrual cycle: potential implications for female sport. Neuropsychologia. 2024:108909. doi: 10.1016/j.neuropsychologia.2024.108909
2. Ecochard R, Stanford JB, Fehring RJ, Schneider M, Najmabadi S, Gronfier C. Evidence that the woman’s ovarian cycle is driven by an internal circamonthly timing system. Sci Adv. 2024;10(15). doi: 10.1126/sciadv.adg9646
3. Barlow A, Blodgett JM, Williams S, Pedlar CR, Bruinvels G. Injury incidence, severity, and type across the menstrual cycle in female footballers: A prospective three season cohort study. Med Sci Sports Exerc. 2024;56(6):1151-1158. doi: 10.1249/MSS.0000000000003391
4. Wang Z, Asokan G, Onnela JP, et al. Menarche and time to cycle regularity among individuals born between 1950 and 2005 in the US. JAMA Netw Open. 2024;7(5):e2412854. doi: 10.1001/jamanetworkopen.2024.12854
5. Zsido RG, Williams AN, Barth C, et al. Ultra-high-field 7T MRI reveals changes in human medial temporal lobe volume in female adults during menstrual cycle. Nat Mental Health. 2023;1(10):761-771. doi: 10.1038/s44220-023-00125-w
