Periods 101 - Menstrual Cycle

Understanding the Menstrual Cycle

1. What Is the Menstrual Cycle?

• Average Length: 21–35 days (28 days is common, but not required)
• Cycle Day 1: The first day of bleeding (start of your period)
• Main Hormones: Estrogen, Progesterone, Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH)

2. The Four Phases of the Menstrual Cycle

Phase 1: Menstrual Phase (Days 1–5)

• The uterine lining sheds.
• Bleeding occurs (your period).
• Hormone levels are low.
• Common symptoms: cramps, fatigue, low energy.

Phase 2: Follicular Phase (Days 1–13)

• Begins on the first day of your period and overlaps with the menstrual phase.
• FSH stimulates the ovaries to mature an egg.
• Estrogen levels rise.
• The uterine lining begins to rebuild.
• Energy and focus may increase toward the end of this phase.

Phase 3: Ovulation (Around Day 14 in a 28-day cycle)

• An egg is released from the ovary.
• Triggered by a surge in LH.
• The egg lives about 12–24 hours.
• This is the most fertile time of the cycle.
• Some people experience mild lower abdominal pain (ovulation pain).

Phase 4: Luteal Phase (Days 15–28)

• Progesterone increases.
• The uterus prepares for possible pregnancy.
• If fertilization does not occur, hormone levels drop.
• PMS symptoms may appear (mood swings, bloating, headaches).
• The next period begins, starting a new cycle.

3. Hormones and Their Roles

• Estrogen: Builds up the uterine lining and supports egg development.
• Progesterone: Maintains the lining after ovulation.
• FSH: Stimulates egg development in the ovaries.
• LH: Triggers ovulation.

4. Fertility and Pregnancy

• Pregnancy can occur if sperm fertilizes the egg during ovulation.
• Sperm can survive inside the body for up to 5 days.
• If fertilization happens, the fertilized egg implants in the uterus.
• If not, the uterine lining sheds during the next period.

5. Common Physical & Emotional Changes Throughout the Cycle

• Changes in energy levels
• Mood shifts
• Changes in appetite
• Breast tenderness
• Acne
• Changes in vaginal discharge

6. Irregular Cycles

• Stress
• Weight changes
• Hormonal conditions (e.g., PCOS)
• Thyroid disorders
• Birth control use
• Adolescence or approaching menopause

7. Tracking Your Cycle

• Mark the first day of each period
• Track symptoms and moods
• Use a calendar or app
• Notice patterns over time

8. When to Seek Medical Advice

• Cycles regularly shorter than 21 days or longer than 35 days
• Severe pain that disrupts daily activities
• Very heavy bleeding
• Missing periods (not pregnant)
• Bleeding between periods