How to Predict Your Fertile Window

Couples often think having a baby should happen naturally, with no real planning when it comes to timing. The reality is a woman’s body is most fertile during a certain window each month, so couples should plan to conceive during that time. 

Since sperm cells only survive for up to five days and eggs live 12-24 hours after ovulation, there’s a narrow window of time to conceive. Fortunately, there are several helpful methods you can try to learn when you’re most likely to be fertile.

Use a Calendar or App

Tracking your menstrual cycle is a good idea, whether or not you’re actively trying to conceive. Knowing the average length of your cycle helps track any irregularities. When trying to conceive, it’s even more important because keeping track of when you start your period helps you predict when you’ll ovulate. 

Each month, write the first day of your period on a calendar or use a period-tracking app. It’s important to record your menstrual cycle for at least six months to reliably predict your fertile window. One menstrual cycle is measured by the time that passes between the first day of your period to the first day of your next period. You’ll need to know the length of your cycle and whether it varies a lot month to month in order to use this method. 

Once you know the length of your cycle, you’ll know when to expect your next period. Count backwards 14 days from that date to approximate when you’ll ovulate. Your fertile window begins five days before and two days after you ovulate. When trying to conceive, you should have sexual intercourse at least every other day during your fertile window. 

Monitor Your Basal Body Temperature

Monitoring your basal body temperature over several months can help you confirm your pattern of ovulation. While it’s not a great method for predicting your fertile window on its own, keeping track of your basal body temperature can be used in combination with other methods to help you narrow down the date you typically ovulate each month.

You’ll need a special basal thermometer, which measures your temperature accurately to a tenth of a degree and can be used orally or rectally. It’s important to measure your temperature as soon as you wake up and before you get out of bed. When you ovulate, your temperature will rise by about 0.5 degrees, so be sure to record your readings.

Examine Your Cervical Mucus

Your cervical mucus changes consistency throughout your menstrual cycle. Familiarizing yourself with its appearance, thickness and texture can help you predict your fertile window. Examine and record the way your mucus looks and feels each day. When you approach your fertile window, your mucus will become slippery and clear.

During ovulation, your mucus changes again, becoming thick and slimy and reaching a consistency that should remind you of egg whites. Compare records of your menstrual cycle, basal body temperature and cervical mucus to help you best predict your fertile window. 

Use Test Kits

Over-the-counter ovulation test kits are widely available and work by measuring the amount of luteinizing hormone (LH) in your urine. Luteinizing hormone rapidly increases a few days before you ovulate. When your test kit detects the increase in LH, you should try to have intercourse as soon as possible since your fertile window will only last one to four days.

Ovulation microscopes are another useful tool to help predict your fertile window. These kits require you to examine the appearance of your saliva, which takes on a fern-like pattern as you approach ovulation. The kit is typically reusable, allowing you to track your saliva over time and familiarize yourself with its appearance at different phases of your cycle. Once you notice the fern-like pattern, you should try to conceive. 

See Your Doctor

While the above methods are good places to start, conditions like polycystic ovarian syndrome and hormonal imbalances can make them less accurate. It’s a good idea to consult a fertility specialist if you’re having trouble conceiving so your doctor can recommend which methods are most appropriate for you. 

Additionally, your fertility specialist can monitor your progesterone levels to help you better predict your fertile window, and use a pelvic ultrasound to confirm whether or not you’ve ovulated. It makes sense to book a fertility consult to screen for conditions that may impact the timing of your fertile window and get expert advice on when to try to conceive.

Remember, each person’s fertility journey is different. If you’ve  tried predicting your fertile window on your own and have been unable to conceive, treatments are available. For example, intrauterine insemination (IUI) is often a good option for women with health conditions that impact ovulation. Medications are used to help your body create a fertile window optimal for conception. Sperm is then placed directly into your uterus to give you your best chance of becoming pregnant. 

Regardless of where your fertility journey takes you, learning to track your cycle and predict your fertile window  helps you know your body’s rhythms better and learn what’s normal for you. Make a habit of tracking your cycle, recording your approximate fertile window and ovulation date, and your attempts to conceive. And remember to bring your records to your appointments. The more information you and your doctor have about how your body is working, the easier it will be to help you end your journey in baby steps!

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