Your menstrual cycle is a monthly hormonal process that prepares your body for possible pregnancy. Understanding it gives you power over your health, your fertility, and your wellbeing.
The average cycle is 28 days — though anywhere from 21 to 35 days is considered normal. It has four distinct phases, each driven by different hormones.
Phase 1 — Menstruation (Days 1–5): Your period. The uterine lining sheds because pregnancy did not occur. Oestrogen and progesterone are at their lowest.
Phase 2 — Follicular Phase (Days 1–13): Follicle-stimulating hormone (FSH) prompts the ovaries to develop follicles. Oestrogen rises, thickening the uterine lining.
Phase 3 — Ovulation (Around Day 14): A surge in luteinising hormone (LH) triggers the release of a mature egg. This is your most fertile window — the egg lives for 12–24 hours.
Phase 4 — Luteal Phase (Days 15–28): Progesterone rises to maintain the uterine lining. If pregnancy does not occur, hormone levels drop and the cycle begins again.
What affects your cycle? Stress, significant weight changes, illness, travel, and hormonal contraception can all shift cycle length. Tracking your cycle for 3–6 months gives you a personal baseline.
When to see a doctor: Cycles consistently under 21 or over 35 days, very heavy bleeding (soaking a pad every hour for multiple hours), or severe pain that limits daily activity all warrant medical review.
