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revised Monday October 28 2013
healthy sexuality

Knowing When You’re Fertile

Knowing when you’re fertile can increase the effectiveness of your birth control method and reduces your chances of an unplanned pregnancy.

There are only certain times during your menstrual cycle when you can get pregnant. Knowing your body and being able to tell when you’re fertile can help you avoid an unwanted pregnancy.

Recognizing Your Body’s Fertility “Clues”

Your body will usually give you clear signals and “clues” as to when fertility is approaching and occurring. You can determine your fertile time by paying attention to these "clues" that your body provides.

If you have irregular periods, there are other signs and body changes to look for that will help you determine when you’re ovulating.

12-16 Days Before Your Period Starts

You can become pregnant only on certain days during your menstrual cycle.

Most women ovulate (release an egg) 12-16 days before their next period is due to start. It’s during this time frame that you can get pregnant. Estimate when your next period will start and then count backwards 12 to 16 days from that day.

It can take up to 4 months to get an idea of when you will most likely ovulate, so as a back-up, use condoms or other birth control methods.

Cervical mucous

Cervical mucous is made by the cervix (the neck of or entrance to the uterus).  There isn’t any discharge right after your period ends, but after a few days mucous appears and has a sticky, creamy feel.  You would notice this discharge when you urinate (pee).

As you get closer to ovulation your cervix will open up and more mucous will be released. This mucous will be thinner and clearer (like a raw egg white) and can be stretched between two fingers.  You can get pregnant at this stage because your cervix is open and the thinner mucous can help move the sperm into the uterus. 

After you’ve ovulated, about two weeks before your next period, your cervical mucous will dry up and you’ll have less discharge. Your cervix will also close up, which will block sperm from getting into your uterus.


Opening of the Cervix

The opening of and position of your cervix - which can be felt at the "top" end of your vagina - can tell you that ovulation is about to happen.

The cervix (the neck of or entrance to the uterus) opens slightly at ovulation, which makes it easier for sperm to travel into the uterus. Your cervix will "feel" more prominent, and if you insert your fingers well up into your vagina will feel more “raised", "open" and "moist." The texture is soft like the lips of your mouth.

Basal Body Temperature (BBT)

Recording your basal body temperature (BBT) over several months will give you some idea of when you’re likely to ovulate.

Your BBT is your early morning temperature before getting out of bed and after at least 3-5 hours of "restful" sleep. Just after ovulation your BBT goes up about half a degree and remains up for approximately the next 12-16 days until you get your period.

The rise in temperature is very slight in some women, and is best seen using a specially calibrated basal thermometer. You might see a very slight drop in temperature before the rise at ovulation. These temperature changes can be as little as .2 to .5 of a degree, not even a whole degree. Illness, activity, restlessness are a few of many factors which can influence that early morning BBT.

How to Chart Your BBT

Start taking your temperature on the first day of a period at about the same time each morning. Keep the thermometer right at your bedside table to reduce any movement before taking your temperature.  Remember, illness, activity, restlessness are a few of many factors which can influence that early morning BBT.

Record these temperatures on a graph to see a line and more easily see these temperature shifts. The lower temperature just before the rise at ovulation is the best time for conception to occur.


Other Signs You Might be Fertile

Other signs that you’re ovulating or about to ovulate include:

  • A bit of vaginal spotting as the egg is released.
  • A mild ache or pain over the ovary that released the egg.
  • Some breast fullness or aching from ovulation until your period starts.

Fertility Management

Many community groups and services in the GTA offer information and group sessions to help couples better understand fertility and how to manage it. These groups include:

  • Customer Contact Centre - Peel Public Health (Tel. 905-799-7700)
  • The Billings Method (Tel. 416-481-5465)
  • The Creighton Model (Tel. 416-465-2868)
  • St. Mike's Family Life (Tel. 416-867-7480 ext. 8193)

Other Factors That Affect  Fertility

Sperm Can Survive for Up to Seven Days

Keep in mind that sperm can survive up to seven days in a women's body. You could have intercourse seven days before you ovulate and still get pregnant.


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Revised: Monday October 28 2013

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