Menstruation, ovulation, and fertilisation: All you need to know

Towards the end of puberty, you start having periods. Having a period means losing some blood through your vagina approximately once a month. Most women and girls lose between two and four tablespoons of blood each month. You can use tampons or sanitary towels (pads) to soak it up.

How does it work?

When you reach puberty, your ovaries start producing oestrogen and progesterone. These hormones make the lining of your womb get thicker once a month and ready for getting pregnant.
Meanwhile, there are hormones also signalling your ovaries to produce and release an unfertilised egg. In most women, this happens once every 28 days or so.

No fertilisation = getting your period.

In general, if you don’t have sexual intercourse around the time of your ovulation (when your ovaries release an egg), it’s unlikely that any sperm reaches and fertilises your egg. So the womb lining, which became thicker to prepare for pregnancy, is shed as menstrual blood. And you get your period! This cycle is called menstruation.

Changes over time

If you’ve only just started having periods, you might not actually ovulate yet. This is a natural way to protect you if your body isn’t actually ready for pregnancy just yet.

During the first year you have your periods, you may only ovulate (release an egg) 20 per cent of the time. So, if you have 12 periods a year, you probably only release an egg two or three times.

Remember, every woman is different and once you’re sexually mature you can get pregnant any month! You can even get pregnant if you’ve never had a period. Don’t think just because you haven’t been having periods for long you don’t need to use birth control. That could be a very big mistake!

Fertilisation and ovulation

Ovulation is the release of eggs from the ovaries.

When you ovulate, if there are no sperm cells in your fallopian tube – either because you haven’t had sex or you used a contraceptive – then the egg won’t be fertilised. Your body then gets rid of the lining of the womb, so mucus and blood come out of your vagina. This is called menstruation, or having your period. In general, it lasts between four and seven days.

Your menstrual cycle runs from the first day of your period to the first day of your next period. This takes about 28 days (four weeks), but different people’s cycles vary between 21 and 42 days (3–6 weeks).

Menstrual cycle © Love Matters


Phase I: Menstruation (day 1 to day 5)
On the first day of your cycle, the tissue from the lining of the womb, the blood, and the unfertilised egg cell leave your body through your vagina. You have your period. In a 28-day cycle, this phase lasts between one and five days. Don’t worry if your period is as short as two days or as long as eight days. This is normal.

Phase II: Follicular (day 6 to day 14)
After your period ends, your womb lining begins to get thicker. Also, one of your ovaries produces one mature unfertilised egg. You may notice changes in vaginal discharge. It may become stickier, white, milky, or cloudy. These changes may signal that you are entering the fertile time of the month.
Just before you ovulate, your vaginal discharge may change to a texture and colour similar to a raw egg white. This discharge can be slippery and clear, which can help sperm travel to the egg. Like the menstruation phase, the length of this phase varies: it can be as short as seven days or as long as 19.

Phase III: Ovulation (day 14)
During ovulation, the ovary releases a mature egg, which passes into the fallopian tube. Some women may feel a slight pain on one side of their lower back or abdominal area around the time of ovulation. This too is normal. Ovulation takes place about 14 days after the first day of your period. Meanwhile, the lining of your womb gets even thicker.

Signs of Ovulation

Some women experience changes when they are ovulating like:

  • A change in vaginal discharge.
  • A brief pain or dull ache felt on one side of the abdomen.
  • An increased desire for sex.
  • A bloated abdomen.
  • A keener sense of vision, smell, or taste.

Phase IV: Ovulation to menstruation (day 15 to day 28)
The released egg travels down the fallopian tube to the womb. The womb lining gets even thicker to receive the egg. If the egg isn’t fertilised by a sperm cell, it dies. Your body gets rid of the extra womb lining and egg cell, and your period starts again.

If the egg cell is fertilised and it settles into the lining of the womb, and your period doesn’t come: you’re pregnant. The menstrual cycle stops until after you give birth.

Can I ovulate right after my period?

It depends on how many days are in your cycle.

If you have a regular cycle – with 28 days from the start of one period to the start of the next – it is less likely that you will ovulate right after your period.

You may bleed up to the seventh day of your cycle, and we know ovulation usually starts 12–16 days before your next period. This means you ovulate between day 12 and 16 of your cycle.

If you have an irregular cycle – lasting just 21 days or as long as 42 days – it’s more likely that you could ovulate soon after your period. For instance, in a 21-day cycle, you may stop bleeding on day seven of your cycle, but you may ovulate between day five and day nine of your cycle.

How can I work out when I’m going to ovulate?

Well, it takes a bit of maths! You have to work backwards from when your period starts. The time you’re likely to ovulate lasts four days, between 16 and 12 days before the first day of your period.

If you have a period every 28 days, take 16 away from 28:
28 – 16 = 12

That means the four days you’re most likely to ovulate begin 12 days after your period starts. So your period starts on day one, and you ovulate between day 12 and 16.

If you have a period every 21 days, take 16 away from 21:
21 – 16 = 5

That means the four days you’re likely to ovulate begin five days after your period starts. So your period starts on day one, and you ovulate between day five and day 9.

Puzzled? Try an online ovulation calculator!

Could I ovulate without having a period?

You could ovulate without having a period if:

  • Your body weight is very low.
  • You’re breastfeeding.
  • You’re approaching the menopause.

Getting pregnant

You’re only able to have a baby during certain times of your life. For many girls and women, this is between about the ages of 15 and 49, when you have monthly periods and are ovulating regularly.
Most girls or young women ovulate every month, in between their periods. During ovulation, an unfertilised egg cell travels out of one of the ovaries and down the fallopian tube to the womb.

To get pregnant, you have intercourse with a man around the time you ovulate – usually about 14 days after the first day of your last period. After sex, the sperm swims up the vagina and into the fallopian tubes. If there’s an egg waiting in one of the fallopian tubes, the tiny sperm tries to burrow their way inside it. If one sperm gets inside the egg, it’s fertilised.

The fertilised egg then moves down the fallopian tube to the womb. Hormones make sure the lining of the womb is ready to receive the egg. If the fertilised egg nestles into the lining of the womb, you become pregnant.

Can I get pregnant when I’m having my period?

Yes. Since sperm can live in the vaginal opening for up to five days after sex, if you have unprotected sex during your period and you ovulate soon after your period, the sperm can fertilise the egg. And you get pregnant.

Period pains

You may not feel so good when you get your period, or right before your period. If this is not you, count yourself lucky!

Many get stomach aches and get in a bad mood. Sometimes you may feel tired, grumpy, or sad right before your period. This is pretty common. Most of it’s related to the changes in your hormones levels.

What can you do when you’ve got period pain?
The best thing to do is look after yourself. Here are some suggestions:

For stomach aches:

  • Use a hot water bottle/bag on your stomach to ease the cramps.
  • Take a paracetamol or aspirin.

For a headache:

  • Take a paracetamol or aspirin.

For bloating or swelling:

  • Cut down the amount of salt you eat for a few days before your period.

For tiredness:

  • Take vitamin supplements that include calcium (or drink milk).
  • Have plenty of rest and try to get eight hours of sleep.

For moodiness:

  • Exercising regularly for up to 30 minutes a day helps maintain a happy outlook on life
  • For food cravings like chocolate:
  • Eat dark chocolate, yoghurt, or drink milk

If you’ve got extreme pain, and these suggestions don’t help or you have problems with irregular cycles or excessive blood flow, contact your nearest health care provider for more guidance.

did you find this useful?

Tell us what you think

Recent Comments (5)

  1. I want to be pregnant ,and…
    I want to be pregnant ,and am unable to calculate my ovulation period,have just finished my mestration to day after my five days of mestrating,pls when is my o ulation period that am likely to be pregnant,pls advise me.

  2. Tnx so much,, appreciate n…
    Tnx so much,, appreciate n God bless you richly,,
    I was able to get all d info I needed through this post,once again,God bless you

  3. This article is so…
    This article is so motivating. I’ve got to get some hidden facts here. Thanks to the writer.


Bold facts and stories about love, sex, and relationships




Click Love matters Naija to send us a message and we will respond shortly.

× Chat with us