Trying for pregnancy

Last updated 13 February 2017 — Last reviewed 01 March 2014

When you start trying for a baby there are many things that can be helpful to know. This includes understanding about ovulation and when is the best time to try for conception, perhaps using an ovulation calculator or predictor kit, and also being the healthiest you can possibly be.

What is the best time for conception?

There are certain days in a woman's menstrual cycle when pregnancy is possible. Pregnancy is technically possible during the five days before ovulation and the day of ovulation. These days are the 'fertile window' of opportunity to conceive. The likelihood of becoming pregnant is dramatically increased if you have intercourse in the three days leading up to and including ovulation.

What is ovulation?

Ovulation is when a mature egg is released from the ovary and pushed down the fallopian tube so it is available to be fertilised.

Periods & ovulation

Sometimes you can have a period but you don't always ovulate. The blood that flows from this type of period is the shedding of the lining of the uterus (womb) but not of an unused egg. Sometimes you can skip a period altogether and it's because you haven't ovulated in that cycle. This is more common in the first two years of having your period, and in the years leading up to menopause when periods stop altogether around age 51.

As you move through the transition towards menopause you can ovulate regularly or irregularly, or even twice in a cycle. Periods can start to become irregular in your 40s and this can affect your opportunity to get pregnant.

There can be other causes for missing periods and not ovulating, such as stress. If you miss your periods on a regular basis, see your doctor.

How do you know when you are ovulating?

These are some signs that ovulation is occurring or about to occur:

Mucus changes Around the time of ovulation a woman may notice her vagina's mucus is slick and slippery.
Abdominal pain During ovulation, some women experience pain which is general or on one side of the abdomen.
Premenstrual-like symptoms

Symptoms such as:

  • breast tenderness
  • abdominal bloating
  • moodiness

Estimating your ovulation period

Use the natural family planning method, an ovulation calculator or an ovulation predictor kit to help you work out when you may be ovulating.

Natural family planning method

The natural family planning method relies on identifying when ovulation has finished based on temperature. There is a small rise in the body's lowest temperature after ovulation has occurred. The temperature rise is about half a degree Celsius. This temperature rise suggests ovulation has already taken place, which means sexual intercourse is unlikely to lead to conception until after the next period.

Ovulation calculator

Work out the length of your average menstrual cycle based on day 1 being the first day of your period and the last day being the day before your next period begins.

28 day cycle

Ovulation usually happens approximately 14 days before the next period. If you have a 28 day cycle, that is around day 14. If ovulation started on day 14, the most fertile window starts on day 9: 

Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7
Day 8 Day 9 Day 10 Day 11 Day 12 Day 13 Day 14
Day 15 Day 16 Day 17 Day 18 Day 19 Day 20 Day 21
Day 22 Day 23 Day 24 Day 25 Day 26 Day 27 Day 28

35 day cycle

If you have a 35 day cycle, ovulation is more likely to happen around day 21, so the most fertile window starts on day 16:

Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7
Day 8 Day 9 Day 10 Day 11 Day 12 Day 13 Day 14
Day 15 Day 16 Day 17 Day 18 Day 19 Day 20 Day 21
Day 22 Day 23 Day 24 Day 25 Day 26 Day 27 Day 28
Day 29 Day 30 Day 31 Day 32 Day 33 Day 34 Day 35

An easy way to estimate when you are most likely to get pregnant is to subtract 17 days from the average length of your menstrual cycle – that's how many days between your last period and the start of your fertile window.

Ovulation predictor kit

You can use an ovulation predictor kit and start testing a few days before your estimated day of ovulation. Continue testing daily until the test comes back positive. A positive result means you are going to ovulate within the next 24-36 hours.

How do you improve your chances of getting pregnant?

Fertility starts to decline after about 28 years of age, drops significantly after 35, and drops very dramatically after 40. Assisted reproductive methods can help, but often cannot overcome the effects of age. 

See your doctor for pre-pregnancy planning. This may include:

  • a reproductive health check including a detailed history and examination looking for factors such as:
    • genetic or medical conditions (e.g. screening for diabetes)
    • medications or substance use
    • an immunisation review (e.g. whooping cough and rubella)
  • blood tests to check for hormone changes to determine if ovulation is occurring
  • partner assessment, such as a sperm test

Managing stress, not smoking, reducing alcohol and caffeine intake, taking time out when needed and generally caring for yourself can help to enhance your own natural fertility.

Being the healthiest you possibly can be before you try to get pregnant is an important part of pre-pregnancy planning. For more information and a very helpful interactive preconception checklist visit Your Fertility: yourfertility.org.au/get-baby-ready

This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at March 2014.

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