When exactly can you get pregnant? All you need to know about the fertile window

Did you know that there are only a few days each cycle during which you can get pregnant? Even if you're regularly having intercourse and you and your partner keep your eggs and sperm in tip-top reproductive shape, this timeframe is limited. Sex can only result in pregnancy on the day of, and five days prior to, ovulation.

Ovulation and the fertile window

Even if you're not familar with the term “fertile window," chances are you may be familiar (or familiar-ish) with ovulation. Ovulation is the phase of your cycle in which one of your ovaries releases an egg into a fallopian tube, where it can await the company of some 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 and instigates your next period. Even though the egg is only viable for 24 hours, sperm are able to survive inside a female body and fertilize the egg for up to five days after intercourse, so any intercourse within five days of ovulation could result in conception - hence, this window of time is called the fertile window. However, the closer to ovulation your intercourse is, the higher the likelihood of conception will be.

When is the fertile window?

The fertile window begins five days prior to ovulation, and ends the day after an egg is released. Supposing a perfectly regular 28-day menstrual cycle with ovulation at Day 14, this would mean that the fertile window lasts between Cycle Days 9-14. However, the vast majority of people don't have completely predictable 28-day cycles, and ovulation can occur at any point during a cycle. And many lifestyle factors, such as stress, may influence your ovulation date. This makes determining the date of ovulation, not just period, crucial for pinpointing the fertile window.

Identifying the fertile window

Though some individuals may have such regular cycles that they have no trouble in determining their fertile windows, for most people, accurately predicting ovulation is far trickier. In the past, people have relied on a number of different methods and tracked several different metrics to predict fertility, but Ovia Fertility is the first fertility tracker capable of making accurate predictions for ovulation by collecting and analyzing all of these different data points, and more:

  • Basal body temperature: Body temperature often dips immediately prior to ovulation, and spikes shortly after
  • Cervical fluid: Becomes more thin and stretchy as you approach ovulation
  • Health symptoms: Ovia has identified correlations between other health symptoms, improving the power of its prediction engines
  • Ovulation tests: These tests strips search for the presence of luteinizing hormone (LH), the hormone that triggers ovulation when released. Ovulation tests can tell you when ovulation is imminent, and has arrived. When used with your Ovia account, ovulation test information can help you and Ovia identify patterns between cycles, and predict ovulation far in advance

Ovia Fertility is the first ovulation predictor that allows you to easily enter all of the pertinent data points listed above in order to make the most accurate projections possible about your fertile window. Ovia collects your data and aggregates it across billions of data points and millions of users to best determine the date of your ovulation and fertile window. 

Now that you know about the fertile window, if you're TTC, learn more about how to track your fertility to get pregnant faster!

Read more
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  • 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.
  • Miller PB, Soules MR. "The usefulness of a urinary LH kit for ovulation prediction during menstrual cycles of normal women." Obstetrics & Gynecology. 87(1):13-7. Web. Jan-96.
  • Pearlstone AC, Surrey ES. "The temporal relation between the urine LH surge and sonographic evidence of ovulation: determinants and clinical significance." Obstetrics & Gynecology. 83(2):184-8. Web. Feb-94.
  • "ASRM Patient Fact Sheet: Optimizing Natural Fertility." ASRM. American Society for Reproductive Medicine, 2012. Web.
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