What is Menstruation?

Menstruation is a natural biological process where the uterus sheds its lining (endometrium) through the vagina, marking the start of a new menstrual cycle. It usually occurs every 21–35 days in people with a uterus, lasting 3–7 days.

The Menstrual Cycle: Stages

  1. Menstrual Phase (Days 1–5)

    • Shedding of the uterine lining.
    • Blood and tissue exit the body.

  2. Follicular Phase (Days 1–13)

    • Pituitary gland releases FSH (Follicle Stimulating Hormone).
    • Ovaries prepare eggs; estrogen rises.

  3. Ovulation (Day 14)

    • Surge in LH (Luteinizing Hormone) causes the release of a mature egg.

  4. Luteal Phase (Days 15–28)

    • Corpus luteum forms, releasing progesterone.
    • Prepares uterus for possible pregnancy.

Diagram: Menstrual Cycle Overview

Menstrual Cycle Diagram

Hormones Involved

  • Estrogen: Builds up uterine lining.
  • Progesterone: Maintains lining after ovulation.
  • FSH & LH: Control egg development and release.

Why Does Menstruation Happen?

  • If the egg isn’t fertilized, hormone levels drop.
  • The uterine lining breaks down and leaves the body.
  • If fertilization occurs, lining supports embryo growth.

Physical and Emotional Changes

  • Physical: Cramps, bloating, headaches, breast tenderness.
  • Emotional: Mood swings, irritability, fatigue.

Surprising Facts

  1. Menstrual blood is not just blood: It’s a mix of blood, uterine tissue, mucus, and other secretions.
  2. Menstruation can affect brain function: Research shows hormonal changes during the cycle can impact memory, attention, and emotion regulation.
  3. Period syncing (menstrual synchrony) is a myth: Recent studies (Yang & Schank, 2020) found no scientific evidence that cycles synchronize among people living together.

Case Studies

Case Study 1: Menstrual Health and School Attendance

A 2022 UNICEF study in Kenya found that lack of access to menstrual hygiene products led to a 20% increase in school absenteeism among girls. Providing free products improved attendance and confidence.

Case Study 2: Menstruation and Athletic Performance

A 2021 study in the British Journal of Sports Medicine found that some athletes experience peak performance during the follicular phase, while others report more fatigue during the luteal phase. Tracking cycles helped optimize training schedules.

Case Study 3: Technology and Menstrual Tracking

Apps like Clue and Flo use AI to predict cycles, symptoms, and fertility windows. A 2023 review in Nature Digital Medicine highlighted how digital tracking improves health outcomes and empowers users to manage symptoms.

Memory Trick

“Every Old Lady Faints”

  • Estrogen (builds lining)
  • Ovulation (egg released)
  • Luteal phase (lining maintained)
  • FSH/LH (hormone control)

Remember: The cycle is a sequence—Estrogen rises, Ovulation occurs, Luteal phase follows, FSH/LH manage the process!

Menstruation and Technology

  • Apps: Track cycles, symptoms, and predict periods.
  • Wearable Tech: Devices monitor temperature and hormone levels for fertility awareness.
  • Smart Pads: Some companies are developing pads that analyze menstrual blood for health data.
  • Telemedicine: Online consultations for menstrual disorders and education.

Connection: Technology makes menstrual health more accessible, personalized, and data-driven.

Recent Research

  • Yang, Z., & Schank, J. C. (2020). “Women’s menstrual cycles do not synchronize.” Human Nature, 31(3), 273–284.
    • Disproved the myth of menstrual synchrony.
  • Nature Digital Medicine (2023): Digital tracking apps improve menstrual health management and empower users with personalized insights.

Fun Fact

The water you drink today may have been drunk by dinosaurs millions of years ago! Water is recycled through the environment, just like the nutrients and hormones in your body.

Revision Checklist

  • [x] Menstrual cycle stages and hormones
  • [x] Physical/emotional changes
  • [x] Surprising facts
  • [x] Case studies
  • [x] Memory trick
  • [x] Technology connections
  • [x] Recent research
  • [x] Fun fact

Quick Quiz

  1. What hormone triggers ovulation?
  2. Name two symptoms of menstruation.
  3. How can technology help manage menstruation?
  4. What did the 2020 study by Yang & Schank discover?

Useful Resources

End of Revision Sheet