Simulation Lab
Simulation Lab
Menstrual Health Studio
Explore a menstrual cycle day by day: what the uterus and ovaries are doing, how the hormones rise and fall, what you might notice, and how to look after yourself.
Cycle length
Cycles from 21 to 45 days are usual for teenagers, and in the first years they often change from one month to the next. Ovulation is about 14 days before the next period, so in a 28-day cycle it is around day 14.
Day 1 of 28
Period
The lining of the uterus wasn't needed this cycle, so it comes away and leaves through the vagina as blood. A period usually lasts 2 to 7 days, and day 1 of the period is day 1 of the cycle.
What you might notice
Bleeding that is often heavier in the first days. Cramps in the lower tummy or back, and feeling tired, are common.
Look after yourself
- Pads, cloth pads, period pants, tampons and cups all work. Change pads and tampons every 4 to 8 hours, more often if it's heavy. Never leave a tampon in longer than 8 hours, and empty a cup at least every 12 hours.
- For cramps, a warm water bottle on your tummy, gentle movement and rest can help.
- If the pain stops you doing everyday things, tell a parent or trusted adult and see a doctor: they can help.
See a doctor if
- a period lasts more than 7 days
- you soak through a pad or tampon every 1 to 2 hours
- periods often come less than 21 or more than 45 days apart, or stop for 3 months
- pain stops you doing everyday things
- you feel faint or dizzy when bleeding: get help that day
- periods haven't started by 15
Hormones across the cycle
The shapes show how each hormone rises and falls; they are not measured amounts.
- Oestrogen
- Progesterone
- LH
- FSH
- Period days
Quick check
About this simulation
About 7 minAwaiting clinical review
Based on:
- ACOG Committee Opinion 651: Menstruation in girls and adolescents, using the menstrual cycle as a vital sign (2015, reaffirmed 2020)
- NHS: Periods; Toxic shock syndrome (tampon use)
- Ministry of Health and Family Welfare, India: Menstrual Hygiene Scheme (RKSK)