WHAT IS THE
MENSTRUAL CYCLE?
WHAT IS THE MENSTRUAL CYCLE?
The menstrual cycle is defined as the time from the first day of your period to the day before your next period begins.
DURATION
It is a recurring process and a typical cycle lasts 28 days but can occur more or less frequently (23 days to 35 days).
WHAT IS HAPPENING TO MY BODY?
During this time a series of natural changes in hormone production occur along with changes to the structures that form part of the reproductive system (namely the uterus and ovaries), these changes are our body's way of preparing for the possibility of pregnancy.
If you are not pregnant, hormones send a signal to the uterus to shed its lining, this flows out of your vagina and is known as your period.
STAGES OF MENSTRUAL CYCLE
MENSTRUAL PHASE
(PERIOD)
The hormone progesterone plunges, your uterus sheds its lining through the small opening in the cervix and appears as blood flowing out of your vagina.
FOLLICULAR PHASE
The hormones oestrogen start to rise, your pituitary gland (at the base of your brain) releases a follicle stimulating hormone (FSH), this stimulates the follicles in your ovaries to mature, the follicles contain your eggs.
OVULATION PHASE
Luteinising hormone (LH) is released by the pituitary gland, oestrogen rise to a peak. An egg is released from its follicle in your ovary and will survive for 12-24 hours.
LUTEAL PHASE
Oestrogen decline and the body starts producing progesterone.
WHEN DO PERIODS START?
MENARCHE, YOUR FIRST PERIOD
Periods start during puberty but the age from which they begin varies from person to person. What are the signs that your first period may be on the way? What else do you need to consider? Learn more, ready, set, go…
PP-UN-WHC-GB-0273 July 2025