Ovia Fertility Calendar with fertile window.

Conception planning and your fertile window

Those who are trying to conceive should understand their fertile window and how to know when it may occur.

What’s a fertile window?

Your fertile window is the day that you ovulate and the five days leading up to that day. The last day of your fertile window, ovulation, is the phase of your cycle when one of your ovaries releases an egg into a fallopian tube. If you’re TTC, this is the part where your egg awaits the company of sperm for fertilization. Once released, an egg only has a lifespan of about 24 hours to be fertilized. If the egg is not fertilized, it disintegrates, triggering your next period.

Even though the egg is only viable for about 24 hours, sperm are able to survive in the female reproductive system for up to five days. This means that if sperm is present in these few days before ovulation, it could result in conception. However, the closer to ovulation that the sperm is there, the higher the likelihood of conception will be. So if you’re TTC with a male partner, this means intercourse close to ovulation is best for baby-making.

When is it?

Old rules of thumb will tell you that ovulation occurs about halfway through a cycle, or 14 days after you get your period. However, time of ovulation can differ greatly from person to person and even cycle to cycle, depending on the length and consistency of an individual’s cycle and any outside influences like stress or malnutrition. Because there are more factors at play here than just time, we need to look beyond just period data to understand when ovulation occurs.

How can Ovia identify yours?

In the past, people have relied on a number of different methods to predict ovulation, but Ovia can pinpoint it with simple data logging. Enter your fertility data – such as cervical fluid, basal body temperature, and physical symptoms – each cycle, and Ovia will analyze that data and make accurate predictions about your fertile window.

Read more


  • “ASRM Patient Fact Sheet: Optimizing Natural Fertility.” ASRM. American Society for Reproductive Medicine, 2012. Web.
  • D.F. Katz, D.A. Slade, S.T. Nakajima. “Analysis of pre-ovulatory changes in cervical mucus hydration and sperm penetrability.” Advances in Contraception. Volume 13, Issue 2-3, pp 143-151. Web. Jun-97.
  • Stephen R. Pallone, MD and George R. Bergus, MD. “Fertility Awareness-Based Methods: Another Option for Family Planning.” Journal of the American Board of Family Medicine. vol. 22 no. 2 147-157. Web. March-April 2009.
  • Murcia-Lora, José María; Esparza-Encina, María Luisa. “The Fertile Window and Biomarkers: A Review and Analysis of Normal Ovulation Cycles.” Persona y Bioética. Vol. 15 Issue 2, p133-148. 16p. Web. July-December 2011.
  • Stanford JB, White GL, Hatasaka H. “Timing intercourse to achieve pregnancy: current evidence.” Obstetrics & Gynecology. 100(6):1333-41. Web. 12/2/2015.

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