Life stages · 5 minute read
First periods and cycle tracking for teens
What can be expected in the first years after menarche and how to track without expecting instant regularity.
Evidence-informed · Editorial review August 2026 · Links to trusted sources are available in the interactive app
Early cycles are still maturing
The first period is called menarche. Cycles are often less predictable in the first few years as the hormone system matures, so a rigid 28-day expectation is especially unhelpful.
Simple tracking is enough
Record the first day of bleeding, how many days it lasts, flow, pain, dizziness, and missed activities. Privacy matters: young users should know who can see data stored on their device or account.
Ask for help when needed
A trusted adult or health professional can help with very heavy bleeding, severe pain, fainting, or periods that raise concern. The Office on Women’s Health advises medical review when a first period has not occurred by age 15.