Learn more about the menstrual cycle and what it means for your body.
What you need to know about the menstrual cycle
- The cycle runs from the first day of your period until the day before the next one.
- An egg is released each month from the ovaries - this is ovulation.
- Hormone levels change in your body during the cycle.
- Everyone has a different cycle.
So, what is the menstrual cycle?
It’s not just your period - which is also called menstruation, that’s why the whole thing is the menstrual cycle!
Instead, the menstrual cycle is a natural process that prepares your body for the possibility of pregnancy each month and runs from the beginning of one period to the start of the next.
During the cycle, your body experiences various hormonal changes, which help to prepare your ovaries and uterus for pregnancy should it occur. Because of these changes, you might feel different over the course of the cycle - some people have trouble sleeping, others have pain, feel bloated, or notice changes in their mood.
Hormones are chemicals your body makes to transmit signals. The ones involved in the menstrual cycle are oestrogen, progesterone, follicle-stimulating hormone (FSH), luteinising hormone(LH).
The menstrual cycle is actually divided into the ovarian (what’s going on with your ovaries, where eggs are released from) and uterine (what’s happening with your uterus) cycles.
How long should my menstrual cycle last?
The length of the menstrual cycle varies for everyone, so don’t worry if yours is different to your friends' or family members'. On average it's around 28 days, but can last between 21 and 40 days. You should also know that it can vary as you get older AND that even if it is normally regular, there can be times when it is irregular.
Phases of the menstrual cycle
The phases of the ovarian and uterine cycles can be easily thought of by whether they’re before or after ovulation, when an egg is released from the ovaries.
Ovarian cycle phases before ovulation
The follicular phase begins on the first day of your period and lasts until ovulation.
During this time, your body is preparing for a potential pregnancy by developing follicles in the ovaries, which contain immature eggs.
The lining of your uterus, called the endometrium, also starts to thicken, getting ready for a fertilised egg.
Uterine cycle phases before ovulation
The period is the beginning of the menstrual cycle and lasts from the first day of bleeding until the last, which can take anything from 4-8 days but is most commonly 5 or 6.
The bleeding is blood from the previous cycle being expelled, and it’s during this time that the endometrium is at its thinnest.
The proliferative phase lasts from the end of your period until ovulation.
It’s when the lining of the uterus quickly thickens (or proliferates) so that an egg can implant into the lining if it is fertilised.
Ovulation occurs around the middle of your cycle, usually between day 12 and day 16 for most women.
This is when one of your ovaries releases a mature egg (formed in a follicle), which then travels down the fallopian tube and is now ready for fertilisation by a sperm.
This is the point of your cycle when you are most likely to get pregnant. Although, remember that you can get pregnant at anytime during your cycle!
It's important to note that the timing of ovulation can vary from person to person and even from month to month. Factors such as stress, illness, and changes in routine can all affect the timing of ovulation.
Ovarian cycle phases after ovulation
The luteal phase starts after ovulation and lasts until your next period begins.
If fertilisation doesn't occur, the corpus luteum (formed from the leftover follicle that released the egg) breaks down, your endometrium sheds and your period starts, marking the beginning of a new menstrual cycle.
If fertilisation does occur, hormones are released that maintain the endometrial lining and support the developing pregnancy.
Uterine cycle phases after ovulation
The secretory phase starts after ovulation and lasts until the start of your next period.
During this phase, the lining of the uterus gets ready to either accept a fertilised egg and support pregnancy or to break down and prepare to be shed during the next period.
It's this time when menstrual cramps can be triggered by hormones, which help start the next period.
And with that, the menstrual cycle starts again!
If you’re looking for more about all things menstrual, we’ve got you covered.
Worried about irregular cycles, what’s normal and what’s not? Read our guide to irregular cycles.
And remember to sign up to the Mihna newsletter for more advice, stories and information about menstrual health, pregnancy, sex and more.