The menstrual cycle is far more than just your monthly period - it’s a finely tuned hormonal rhythm that impacts your mood, energy, fertility, and even your brain function. This cycle is controlled by a complex interaction between the brain, ovaries, and uterus, guided by key hormones: estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).

The menstrual cycle is a monthly hormonal rhythm that prepares the body for the possibility of pregnancy. It’s driven by fluctuations in estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). Day 1 of your cycle is the first day of menstrual bleeding, and the cycle continues until the day before your next period starts. On average, cycles last 28–35 days, but anything between 21–35 days can be considered normal.
The purpose of the cycle is to release an egg (ovulation) and prepare the uterus for possible implantation. If pregnancy doesn’t occur, hormone levels drop and the uterine lining sheds — your period.

When to expect it

Most people get their first period between ages 9–15. Once cycles establish, they tend to follow a consistent rhythm. However, stress, diet, exercise, medical conditions, and hormonal contraception can all impact timing.

How regular it should be

A healthy cycle is one where the length is fairly consistent month-to-month. Large variations, skipped periods, or overly heavy/painful periods may signal an underlying hormonal or reproductive issue and should be discussed with a healthcare provider.