A menstrual cycle is more than the days you bleed. It is a monthly process driven by hormones, and knowing where you are in it can help you make sense of how you feel.
How long is a cycle?
The cycle is counted from the first day of bleeding to the day before the next period starts. In adults the average is about 28 days, and a typical range is 21 to 35 days. Bleeding usually lasts 2 to 7 days.
1. Menstrual phase (roughly days 1–5)
When there is no pregnancy, the lining of the uterus sheds. Estrogen and progesterone are low. You may feel tired, have lower abdominal cramps or notice mood changes.
2. Follicular phase (from the start of the period until ovulation)
The pituitary gland releases follicle-stimulating hormone (FSH), and follicles grow in the ovaries. Estrogen rises and the uterine lining thickens again. Many people notice more energy in this phase.
3. Ovulation (often around the middle of the cycle)
A surge of luteinizing hormone (LH) causes a mature egg to be released. The egg survives about 12–24 hours, while sperm can live up to 5 days, so the fertile window lasts around 6 days.