1. Flo - ovulation calendar, period tracker, and pregnancy app
  2. Getting pregnant
  3. Trying to conceive
  4. Fertility

Fertile Window: What, When, and How Long Is It?

While the average menstrual cycle lasts somewhere between 21 and 35 days, conception can only occur on about 3 of those days. However, your fertile window may be significantly longer. Let Flo teach you how to pinpoint your fertile window to make informed reproductive decisions.

Fertile window

What is a fertile window?

The term “fertile window” refers to both the period in which unprotected sex could result in pregnancy as well as to your ovulation window. The latter is a 24-hour period of time when conception can occur. (Some cycles the ovulation window can last up to 72 hours.)

Trying to conceive?

Trying to conceive?

Flo will help you get pregnant faster!

If you’re trying to get pregnant, this distinction isn’t particularly important. However, if you’re trying to avoid pregnancy, failing to understand the difference between these two windows might result in an unplanned pregnancy.

Conception can result from sex that didn’t happen during your ovulation window. Sperm can live in your body for up to five days. In fact, certain studies have even put that number at seven days.

The bottom line? Sexual intercourse outside of your ovulation window could potentially lead to pregnancy because sperm can survive inside your uterus until an egg is released.

How long does your fertile window last?

Strictly speaking, conception only occurs within 24 hours of ovulation. However, it’s possible for your body to release eggs from both ovaries in a single cycle, as much as 24 hours apart. Therefore, your ovulation window can last up to 72 hours.

A woman holding a clock

Keep in mind that your fertile window is much longer. It begins four or five days before ovulation. However, because ovulation can shift, it’s important to remember that you’re potentially fertile on any day that you observe cervical fluid, or a clear to whitish discharge. Sometimes it’s sticky or lotiony. If you’re about to begin ovulating, it’s wet and slippery like egg whites. Sperm have the highest chances for survival in wet, slippery cervical fluid.

Why is your fertile window important?

Identifying your fertile window is absolutely key to getting pregnant, avoiding pregnancy, and developing a better understanding of your cycle. It helps you time sex for successful conception or lets you know when backup birth control is needed. It’s also useful for gauging how ovulation hormones are linked to stress and anxiety or gastrointestinal issues. 

Identifying your fertile window is absolutely key to getting pregnant, avoiding pregnancy, and developing a better understanding of your cycle.

Lastly, a working knowledge of your fertile window is instrumental in addressing fertility complications like irregular ovulation or poor quality cervical fluid.

How do you calculate your fertile window?

The most effective way to determine your fertile window is by charting your cycles, observing cervical fluid, and tracking basal body temperature. Ovulation test kits will improve the accuracy of your predictions. 

Ovulation typically occurs between day 11 and day 21 of your cycle. It’s important to note, though, the date of ovulation can vary with each cycle. So simply counting the number of days isn’t very reliable.

The most effective way to determine your fertile window is by charting your cycles, observing cervical fluid, and tracking basal body temperature. Ovulation test kits will improve the accuracy of your predictions.

If you track your cervical fluid, you’ll know you’re about to begin ovulating once it takes on an egg-whitish consistency. When checking basal body temperature, an increase of at least three-tenths of a degree (compared to the last six days) signals ovulation. The rise in temperature, however, must be sustained for at least three days. 

The next 12 to 24 hours offer your best chance of getting pregnant. Since you cannot confirm that ovulation has occurred until it’s over, begin trying to conceive at the first sign of cervical fluid. For more information, contact your OB-GYN. 

Can you get pregnant outside of your fertile window?

Although conception only happens in the first 12 to 24 hours after ovulation, it’s definitely possible to get pregnant from sex outside of your predicted fertile window. Again, this is because sperm can survive inside the uterus for several days.

Although conception only happens in the first 12 to 24 hours after ovulation, it’s definitely possible to get pregnant from sex outside of your predicted fertile window.

Occasionally, ovulation may occur at a different point in your cycle. Stress, anxiety, travel, and changes to your normal routine all affect the delicate hormonal balance that triggers ovulation. For example, you might usually ovulate around day 20 but experience 1 or 2 cycles per year where ovulation occurs much earlier or later.

Does a fertile window occur every cycle?

In short, no. Even if you’ve always experienced regular periods, you’ll have at least a few anovulatory cycles (where ovulation does not occur) in your lifetime. Sometimes bleeding is still present, and you won’t even be aware you didn’t ovulate. Furthermore, since the start of your period is dependent upon ovulation date, you may just skip a period.

Even if you’ve always experienced regular periods, you’ll have at least a few anovulatory cycles (where ovulation does not occur) in your lifetime.

People with polycystic ovary syndrome (PCOS) can go without ovulating for months or years at a time and have irregular periods. If you’re struggling to conceive and suspect ovulation issues are to blame, contact your doctor. A simple blood test and ultrasound can confirm if this is the case.

Determining your fertile window provides vital information about your body’s hormonal functions and overall reproductive health. It’s also especially important for those who are actively trying to conceive or avoid pregnancy.

https://www.parents.com/getting-pregnant/ovulation/fertile-days/how-to-find-your-fertile-window-when-youre-trying-to/

https://www.webmd.com/baby/healthtool-ovulation-calculator

https://www.womenshealth.gov/pregnancy/you-get-pregnant/trying-conceive

https://www.webmd.com/infertility-and-reproduction/guide/sperm-and-semen-faq

https://www.medicinenet.com/menstruation/article.htm

Read this next