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Fertility Factors:

What is unexplained infertility?

If you’ve tried to get pregnant for a year or more, and there’s no explanation for your lack of success, you have unexplained infertility. This does not mean you won’t conceive. But how long should you wait before starting fertility treatment? The answer depends on your expected chance of conceiving with and without fertility treatment, and on personal preferences. Our Pregnancy Probability Tool can help you decide what to do next.

Pregnancy Probability Tool

The Pregnancy Probability Tool is designed for couples where:

  • the woman has regular menstrual cycles, has at least one open fallopian tube and is 42 years old or younger
  • the man has had a sperm test 

Using four questions, it gives you three estimates of your chance of pregnancy over the next year if you:

  • just keep trying
  • have simple fertility treatment such as intrauterine insemination (IUI) 
  • have more complex fertility treatment such as IVF 

Pregnancy Probability Tool Icon

Your probability of conceiving within the next 12 months:
Without treatment
With six cycles of IUI treatment
With two cycles of IVF treatment
Your estimated chance of conceiving without treatment
40% or above You have a good chance of avoiding the need for costly fertility treatments. Keep trying and if not pregnant after 6-12 months get advice from a fertility specialist about the next steps
30% to 40% You have a good chance of avoiding the need for costly fertility treatments. Keep trying and if not pregnant after 6 months get advice from a fertility specialist about the next steps
less than 30% Get advice from a fertility specialist about the next steps, as soon as possible
View your probability results for 6 months
Survey feedback

Should I try for another six months?

Although IVF might look like the fastest option, it can be expensive, costing most people thousands of dollars. And like any medical procedure, IVF carries risks, particularly for women. So, if you have a 30% chance or more of a spontaneous pregnancy, trying for another six months can help you avoid the costs and risks of fertility treatment without reducing your chance of a baby. Talk to your doctor about your options and consider holding off on treatment if you have a good chance of getting pregnant without it.

How to improve your chance of a pregnancy

Get your timing right
Your window of opportunity to fall pregnant each month is small. Pregnancy is only possible if you have sex during the three days leading up to ovulation or on the day of ovulation. This calculator can help you work out when you are likely to ovulate. Knowing your body and how it changes when ovulation is approaching can help. For example, a few days before ovulation, vaginal mucus changes and becomes clear and slippery; a bit like egg white which is perfect for sperm to swim along! If you notice this, it’s time to have sex.


Be as healthy as possible
Some lifestyle factors can affect your chance of getting pregnant and the health of your baby. When trying to conceive, men and women should both strive to:

  • Be in the healthy weight range
  • Not smoke
  • Eat a healthy nutritious diet and exercise regularly
  • Take a folate and iodine supplement (women only)
  • Avoid alcohol
  • Avoid contact with toxic chemicals in the work and home environments
  • See a doctor if you suspect an infection or other inflammation. 


Have a pre-conception health check
See your doctor for a pre-conception health check to make sure you’re as healthy as possible. Check that your immunisations are up-to-date and that any medication or complementary therapy you’re taking is safe.

  • References

    Expectant management:

    Hunault CC, Habbema JD, Eijkemans MJ, Collins JA, Evers JL and te Velde ER. Two new prediction rules for spontaneous pregnancy leading to live birth among subfertile couples, based on the synthesis of three previous models. Hum Reprod 2004;19:2019-2026.

    van der Steeg JW, Steures P, Eijkemans MJ, Habbema JD, Hompes PG, Broekmans FJ, van Dessel HJ, Bossuyt PM, van der Veen F and Mol BW. Pregnancy is predictable: a large-scale prospective external validation of the prediction of spontaneous pregnancy in subfertile couples. Hum Reprod 2007;22:536-542.

    van der Steeg, J. W., P. Steures, M. J. C. Eijkemans, J. D. F. Habbema, P. G. A. Hompes, J. A. M. Kremer, L. van der Leeuw-Harmsen, P. M. M. Bossuyt, S. Repping, S. J. Silber, B. W. J. Mol and F. van der Veen (2011). "Role of semen analysis in subfertile couples." Fertility and Sterility 95(3): 1013-1019.

    van Eekelen R, Scholten I, Tjon-Kon-Fat RI, van der Steeg JW, Steures P, Hompes P, van Wely M, van der Veen F, Mol BW, Eijkemans MJ, et al. Natural conception: repeated predictions over time. Hum Reprod 2017;32:346-353.

    van Eekelen R, McLernon DJ, van Wely M, Eijkemans MJ, Bhattacharya S, van der Veen F and van Geloven N. External validation of a dynamic prediction model for repeated predictions of natural conception over time. Hum Reprod 2018;33:2268-2275.


    Steures P, van der Steeg JW, Mol BW, Eijkemans MJ, van der Veen F, Habbema JD, Hompes PG, Bossuyt PM, Verhoeve HR, van Kasteren YM, et al. Prediction of an ongoing pregnancy after intrauterine insemination. Fertil Steril 2004;82:45-51.

    Custers IM, Steures P, van der Steeg JW, van Dessel TJ, Bernardus RE, Bourdrez P, Koks CA, Riedijk WJ, Burggraaff JM, van der Veen F, et al. External validation of a prediction model for an ongoing pregnancy after intrauterine insemination. Fertil Steril 2007;88:425-431.


    McLernon DJ, Steyerberg EW, Te Velde ER, Lee AJ and Bhattacharya S. Predicting the chances of a live birth after one or more complete cycles of in vitro fertilisation: population based study of linked cycle data from 113 873 women. BMJ 2016;355:i5735.