What's a normal menstrual cycle and what's not?

Your menstrual cycle starts on the first day of your period and ends when the next period starts.

Day one of your cycle is always the first day of bleeding. The average length of a cycle is 28 days, but it can be significantly shorter or longer. There is no ‘normal’ cycle length.

In a 28-day cycle, you would ovulate, or release an egg, around day 14. Just prior to this is the best time to try for a baby so you and your partner should try to have sex every couple of days around that time, for example days 10, 12 and 14.

Some women have regular shorter or longer cycles. The length can range from around 22 to 35 days.

If you have a 22-day cycle, you could ovulate just a few days after your period ends and should be trying to have sex just before or on day eight of your cycle.

If your cycle is longer than average, for example 35 days, your ovulation will take place around day 21. So having sex every second day just before that time will maximise your chances of falling pregnant.

Length of period (days)Likely ovulation day
228
2410
2612
2814
3016
3218
3420
3622


Women who have irregular periods may find it difficult to determine when ovulation takes place. Learning to chart your temperature and cervical mucus may help, or you can buy an ovulation kit at your local chemist.

Whether your periods are regular or not, it's a good idea to keep a record of your periods for a few months. It will help to establish your average cycle length and give you an idea as to when ovulation is likely to take place.

Most importantly, if you're trying for a baby, you'll boost your chances of conceiving by having sex every two to three days throughout your cycle. It'll be less stressful than concentrating all your baby-making efforts around the time you think you're about to ovulate – and more fun!

You should see your doctor if:
  • You're younger than 37 years old and have been trying for a baby for longer than one year.
  • You have bleeding between periods, or after sex.
  • You're aged over 36 and have been trying to conceive without success for longer than six months.
  • You have a known problem that could affect your fertility.
That way, your doctor will be able to look into why you're not conceiving and explain the options that are available to you.

Learn more about ovulation.
Hanna Mills Turbet is a digital journalist, editor and social media producer. She was Assistant Editor and contributor for BabyCenter.

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