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Understanding your menstrual cycle

Understanding your menstrual cycle

Let’s learn about our periods!

In this section you’ll learn about the 4 phases of the menstrual cycle, the average 28 day cycle and periods shorter and longer than 28 days.

The Four Menstrual Phases

The period cycle is complex but it can be easy to understand when you break it down into its 4 phases. Each day of your menstrual cycle is part of one of these phases so we’ll take a look at how each day maps onto the phases afterwards.

Your menstrual cycle goes through 4 phases (in order): the menstrual phase, the preovulatory phase, and postovulatory phase.

menstrual phase
Menstrual Phase

This is when you bleed and get your period. This starts at the first day of your period cycle and for most girls this lasts anywhere between 3 to 7 days.

Your endometrial lining sheds and exits your body through your vagina.

preovulatory phase
Preovulatory Phase

Now that you’ve had your period, your cycle enters the preovulatory phase. You no longer have an endometrial lining so your body prepares a new one all over again.

Your endometrial lining starts to thicken and an ovum in your ovaries starts to mature as it gets ready to be released.

ovulation phase
Ovulation Phase

About two weeks before your period, your ovaries releases the now mature ovum and you ovulate!

In this diagram, you can see the ovum released from the right ovary where it then begins its journey down the fallopian tube towards the uterus. The ovum is actually much smaller than that. It is actually closer to the size of the tip of your pencil.

post ovulatory phase
Postovulatory Phase

Your menstrual cycle then enters the postovulatory phase where your endometrial lining continues to thicken.

When you don’t become pregnant, your uterus sheds the lining, marking the start of your period and the cycle starts all over again at the Menstrual Phase.

The average 28 day cycle

menstrual cycle

Another way we can understand the menstrual cycle is by looking at how the days of our cycle map onto the menstrual phases. The average period cycle lasts 28 days so we’ll use that in our example.

Remember, 28 days is just the average and not all girls have a 28 day cycle. Some girls may have longer cycles and some girls may have shorter cycles and this is normal.

So what’s happening during your cycle?
Days 1-5
This is the menstrual phase and this maps on to the days that you have your period and bleed.
Days 6-14
The days after your period map on to the preovulatory phase. This starts from the first day after your period until the day you ovulate. On these days, your uterus is starting to build a brand new endometrial lining.
Day 14
This day maps onto the ovulation phase. Ovulation typically happens about half way through your cycle so for a 28 day cycle, this will most likely occur on day 14. During this time, an ovum is released from your ovary and into the fallopian tube.
Days 15-28
The days after you ovulate, map onto the postovulatory phase. During this time, your uterus continues to build the endometrial lining and it continues to thicken.

Pretty easy right? Got questions? Leave a comment below!

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About Dedy Wong

Dedy is the founder of The Period Blog and creator of The Little Red Kit. Her period is around 30 days long and likes to use pads and tampons -although she has tried just about everything including menstrual cups and period subscription boxes!


  1. Adediran azeezat mosunmola

    My period is irregular, am using forever aloe Vera berry nectar and forever gin chain. So I need information about my problem

  2. Achomba Blessing Ifeoma

    My period started on 5th September, I had unprotected sex on 8th September and my period ended on 10th. Is it possible for me to get pregnant ? Thanks

  3. Can one get pregnant during pre-ovulatory phase?

    • Hi Aldo,

      Yes, in fact you can! This is due to the fact that sperm can live inside a woman’s uterus for up to 5 days – and during this time you may enter the ovulatory phase which may result in pregnancy. I hope that helps!

      Your friend,
      The PEriod Blog

  4. In December 6 2015 I had ma menstration. On the same December I had ma men station again from 27 December 2016 n it ended on the 1 Jan 16
    I had sexy from 2 to 4

  5. Yes it’s your period
    Because it comes monthly
    It’s normal for your period for the first 2 years it can skip a month or more

    I hope you learn much from this

  6. so upon reading this,days 6-14 (pre-ovulatory phase, means you are safe to have sex? and not get pregnant?

  7. Am getting married. Pls I want to know how to get pregnant before my wedding day.

  8. Hi! I was wondering if you could help me out. I’m going to be a freshman in high school and I can’t tell if I’ve gotten my period yet or not. I always have white discharge in my underwear but one day I noticed that it was a little more than usual and it was reddish brown. It happened once and then again three months later. It is wetter and more gooey than normal discharge and is brown. I can’t tell if this is my period or not. What is period blood like? Thank you so much!

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