The Right Timing: Why It Matters When Trying to Conceive

One of the most common — and preventable — challenges I see when working with people trying to conceive is simply missing the fertile window. Even with healthy eggs, sperm, and reproductive anatomy, timing sex outside of the fertile window can dramatically lower your chances of falling pregnant.

So, what is the fertile window?

The fertile window refers to the days in a menstrual cycle when conception is most likely. Sperm can survive in the female reproductive tract for up to five days, but an egg is viable for only around 12–24 hours after ovulation. This means your best chance to conceive is during the five days leading up to ovulation, and on the day of ovulation itself. Having intercourse during this window maximises the likelihood of sperm meeting the egg.

Research shows that many couples underestimate the importance of timing, or miscalculate it entirely (Stanford et al., 2002). While period tracking apps are helpful, they may not account for cycle variability, stress, or other lifestyle factors that can shift ovulation earlier or later.

How can you identify your fertile window?

👉 Track your cycle. Over several months, note the first day of your period, the cycle length, and any symptoms such as cervical mucus changes.

👉 Use ovulation predictor kits (OPKs). These detect the surge in luteinising hormone (LH) that happens 24–36 hours before ovulation.

👉 Check cervical mucus. Fertile cervical mucus is clear and stretchy, similar to raw egg white, indicating oestrogen is peaking and ovulation is near.

👉 Try an ovulation calculator. Online tools — like this one on my website — can give you a rough estimate, but should be used in combination with other signs for the best accuracy.

If your periods are irregular, or you’ve been trying to conceive for over six months (if over 35) or 12 months (if under 35) without success, I recommend speaking to a fertility specialist to explore why timing alone may not be enough.

Why does timing matter so much?

There is only one ovulation per menstrual cycle in most women. Missing this window means waiting another entire month for the next opportunity. For people who already have reduced ovarian reserve or are older, every cycle counts.

It’s important to know that even perfectly timed intercourse does not guarantee pregnancy, but it does give you the best possible chance. Understanding your fertile window is a powerful first step towards taking charge of your reproductive health.

Key takeaway

If you’re trying to conceive, make timing your focus. Learn your cycle patterns, use tools to predict ovulation, and have intercourse during the fertile window. And if you’re finding it difficult, remember you’re not alone — evidence-based support is available, and I’m here to help guide you every step of the way.

Ready to start your journey?

Book your fertility consultation or try my ovulation calculator today.

References

Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). Planning for Pregnancy and Parenthood; 2023. ranzcog.edu.au

Better Health Channel (Victoria State Government). Fertility and Timing; 2023. betterhealth.vic.gov.au

Stanford JB, White GL, Hatasaka H. Timing intercourse for optimal pregnancy rates. Obstet Gynecol. 2002;100(6):1333–1341. doi:10.1016/S0029-7844(02)02382-0