What is the Fertile Window?
By Takera Mitchell, RN, BSN
The path to pregnancy can be quite magical. But for some who don’t get pregnant right away, the family planning and growing path can become stressful. For many, it can come as quite a shock to learn that there are only a couple of days each month when you may be able to get pregnant. When you think of how many things along the journey have to align for the trying to conceive (TTC) process to actually result in a chance of conceiving, you realize that the fertile window isn’t just a number of days—it’s an important window of time to pay attention to and track so that there is actually a chance of pregnancy.
Understanding the fertile window
The fertile window is the period of time during your menstrual cycle when you are most likely to get pregnant. It begins 5 days prior to when ovulation occurs and ends with the day after ovulation. On the day of ovulation, an egg is released from the ovaries so that it can be fertilized by sperm in the fallopian tubes. Sperm can survive for up to 5 days, and a mature egg can survive in the fallopian tube for about 24 hours after ovulation, which is why it’s important to start trying in the days leading up to and during ovulation. Once you’re within your fertile window, it’s recommended to have intercourse every day, or every other day. The highest chance of getting pregnant occurs when sperm are present in the fallopian tubes at the time ovulation happens. That timing provides the highest likelihood of fertilization, which will then hopefully lead to implantation. You can typically test for pregnancy 14 days after ovulation.
How to track your fertile window
The first step in tracking your fertile window is tracking your menstrual cycle. Your cycle is divided into 4 different phases:
- Menstruation
- Follicular phase
- Ovulation
- Luteal phase
The first day of menstrual bleeding is the first day of your cycle (known as “cycle day 1”). In an average menstrual cycle that lasts 28 days, ovulation typically occurs on cycle day 14.
You can keep track of your menstrual cycle using a simple calendar with paper and pen, or with one of the many digital apps available. From there, you can also begin tracking your fertile window, using the same basic resources.
One way to track your fertile window and better understand when ovulation is likely to occur is using fertility awareness methods. You may notice spotting, abdominal cramping, changes in your cervical mucus, changes in your basal body temperature, and other physical changes during your fertile days. These, along with other symptoms, may indicate ovulation is happening. Having sexual intercourse during the fertile window, when signs of ovulation are present, increases the chances of getting pregnant. Here are a couple of examples of how these fertility awareness methods work:
Basal body temperature method
Your basal body temperature (BBT) can be found when your body is fully “at rest,” meaning you should take your temperature first thing in the morning—ideally before you get up, eat, or do anything else. During ovulation, your temperature will increase (very slightly). Thus, while the BBT method is helpful for cycle tracking and getting to know your cycle month to month, it’s not always the best way to determine when exactly is the right time to try to conceive when used on its own.
Cervical mucus method
The cervical mucus method works by tracking what yours looks and feels like during your cycle, specifically before ovulation. You’ll typically start to see much more of it and notice a different texture (closer to egg whites). After ovulation, you’ll usually start to see less of it, and if you do see it, your cervical mucus will go back to being a thicker texture. Similar to BBT, it’s helpful to track your cervical mucus changes from cycle to cycle in order to get to know how things change from menstruation to ovulation, and to optimize your timing for TTC.
Ovulation predictor kits
Another way to help figure out your most fertile days is by using ovulation predictor kits (OPKs). These ovulation tests can help determine when your “LH surge” occurs, meaning your luteinizing hormone has peaked, signaling that ovulation will take place within a day or two. Be sure to read the instructions for your specific ovulation calculator, as some will notify you of your full fertile window, while others will only let you know when ovulation is about to take place.
It’s not always enough to just have intercourse randomly when trying to get pregnant. You should be strategic and be able to plan and predict your fertile window to maximize the opportunity to conceive. The timing must align with ovulation. Detecting your fertile window may take some time and practice, especially if you have irregular cycles, so be sure to start tracking your menstrual cycle and ovulation for a few months using a calendar as soon as you can. Once you can figure out the length of your menstrual cycles and when ovulation is happening, you will have a better chance of timing intercourse that improves the opportunity of getting pregnant.
Again, be sure to take notice of these clues when trying to determine your fertile window:
- Menstrual cycle tracking (from menstrual period through the luteal phase to the start of your next menstrual period)
- Ovulation timing (mid-cycle, when the follicle or egg is released from the uterus)
- Physical changes around the time of ovulation (cramping, spotting, basal body temperature, cervical mucus)
If you have any questions about your menstrual cycle, ovulation, fertile window, or tracking, be sure to contact your healthcare provider. The path to pregnancy usually requires planning. When you are equipped with the knowledge of your reproductive health and how to navigate the journey, which includes understanding the prime fertile time within your window, the journey can be a bit easier to reach your goal of pregnancy.
