Cycle basics
Understanding the menstrual cycle
Awaiting clinical reviewA cycle runs from the first day of one period to the first day of the next. For most adults it lasts somewhere between 21 and 35 days.
Your cycle is controlled by hormones that prepare the body for a possible pregnancy each month. If pregnancy does not happen, the lining of the uterus is shed — that is your period.
Day 1 is the first day of real bleeding (not spotting). Cycle length varies between people and can change a little from month to month.
When to seek medical assessment
- Your cycles are regularly shorter than 21 or longer than 35 days.
- Your periods stop for 3 months or more and you are not pregnant.
Practical next steps
- Log the first day of each period.
- Note when bleeding ends so your period length can be calculated.
Sources
Version 0.1-draft · Reviewer: pending · Review date: pending