Phases of the Menstrual Cycle

The menstrual cycle is a complex but beautifully coordinated process influenced by key hormones that impact your physical, mental, and emotional health. Here’s a breakdown of the four main phases:

1. Menstrual Phase

This is the start of the cycle—your period. Estrogen and progesterone levels drop, signaling the uterus to shed its lining. This phase typically lasts 3–7 days, though the exact duration varies from person to person.

2. Follicular Phase

Beginning on the first day of your period and lasting until ovulation (around day 14–16), this phase is driven by follicle-stimulating hormone (FSH). FSH prompts the ovaries to develop follicles, one of which will mature into an egg.

3. Ovulation Phase

During ovulation, estrogen peaks, triggering a surge in luteinizing hormone (LH), which causes the release of a mature egg from the ovary. This typically happens mid-cycle. A slight increase in basal body temperature can signal ovulation is occurring.

4. Luteal Phase

After ovulation, estrogen and progesterone rise to prepare the body for possible pregnancy. If pregnancy doesn’t occur, these hormone levels fall—leading to PMS symptoms like bloating, mood swings, cravings, and sleep disturbances. This phase lasts about 11–17 days before the cycle resets.