Calculate Your Fertile Window

Timing is everything

If you’re trying to fall pregnant, the timing of when you and your partner have sex is critical. Our new online calculator will help you understand your Fertile Window - so you know the best time to have sex to give you the highest chance of conceiving.

When am I most fertile?

The most fertile time in your cycle are the days leading up to ovulation, before the egg is released from the ovary.  After ovulation the egg survives for just 24 hours, while sperm retain fertilising capability for two to three days in the fallopian tubes.   For this reason, we recommend that couples have sexual intercourse every two days throughout the females Fertile Window.  This means that sperm are ready and waiting for the egg when the female ovulates.  If you wait until after the female has ovulated before you have sex, you will most likely have missed the opportunity for conception that month.

When does conception take place?

Conception starts at the moment of fertilisation, when the sperm penetrates the outer shell of the egg, and an embryo is formed. Over the next four to six days the embryo moves down the fallopian tube to the uterus, where it implants in the uterus lining and hopefully continues to grow. To check if you are pregnant, you should wait two weeks after ovulation before undertaking a pregnancy test.

Calculate Your Fertile Window

To calculate your Fertile Window, you need to determine what day you ovulate.To do this, you need to know the length of your menstrual cycle (which tends to vary from 23 to 35 days). To calculate this – you should note how many days have passed from the first day of bleeding in your last period, to the first day of bleeding in your next.From this figure, subtract 14 days from the end of your current cycle to determine the day you ovulate.If you have irregular menstrual cycles, or your cycle length varies from month to month, it will be difficult to calculate your ovulation date. Ovulation urine tests may be useful, and you should consider seeking further advice from your GP or a Fertility Specialist.

How long should I try for, before seeking specialist advice?

Conception is a complicated sequence of events because all of the following need to be in place for it to occur:

  • Regular egg production by the ovaries (ovulation)
  • Healthy sperm, with the ability to move (motility) and the correct shape (morphology)
  • Unblocked and healthy fallopian tubes and uterus

The number one factor affecting a couple’s chances of conceiving is the woman’s age. The number of healthy eggs a woman’s ovaries contain will dramatically decline with age; and especially for women over 35. Most people start to consider seeking professional advice after six months of trying to conceive naturally without success. This is even more important if you’re over 35.

Want to know more?

If you’re keen to know more about the menstrual cycle, read about female reproduction….

If you’d like to consult with a Fertility Specialist about irregular periods and ovulation, or difficulties conceiving naturally, then please contact us.


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