How do I know if my period is too heavy?

If you're soaking through protection every hour or two, changing it overnight, or feeling tired and run-down, that's worth checking with a clinician.

Why might a bleeding disorder be checked?

In teenagers, heavy periods can occasionally be the first sign of a bleeding disorder, so a clinician may include this in the assessment.

Gynaecology, Explained Simply

Name: Heavy Periods in Teens | Adolescent Gynaecology | Gynaec.com.au
Creator: Dr Priya Sivadas
Published: 2026-07-01

Heavy periods in teenagers

Some teenagers have periods that are heavier than usual, and this can affect school, sport and how you feel day to day. This page explains what counts as heavy and what a check-up involves.

It is general information for teens and parents and is not personal medical advice.

Key points

A period that soaks through protection quickly or lasts a long time may be heavy.
Heavy periods can affect energy levels and daily life.
In teenagers, an underlying bleeding disorder is a bit more likely and worth considering.
A simple assessment can find the cause and options.

Last reviewed 1 July 2026

What counts as a heavy period

A period may be considered heavy if it affects daily life.

Soaking through a pad or tampon every hour or two
Needing to change protection during the night
Periods lasting longer than about a week
Passing large clots, or feeling tired and run-down

What can cause it

In the early years of having periods, hormonal patterns are still settling, which can make some periods heavier. Importantly, in teenagers an underlying bleeding disorder is a little more likely than in adults, so this is something a clinician will keep in mind and may check for.

What an assessment involves

An assessment usually starts with a conversation about your periods and general health. A clinician may arrange blood tests, including to check iron levels and, where appropriate, clotting, and sometimes an ultrasound. The aim is to understand the cause and talk through what can help.