Published:
November 11, 2022
When trying to get pregnant, there’s a very specific timeframe during your monthly cycle that can greatly increase your chances of getting pregnant. Known as the “fertile window,” the days just before, and on the day you ovulate, are the days where you have the highest chance of conception. And while a woman with a 28-day cycle typically ovulates around cycle day 14, it’s not always a sure thing—not to mention, many women don’t have a 28-day cycle!
So how do you know exactly when ovulation happens—especially if your cycle isn’t always predictable—so that you can time everything correctly? Luckily there are a few helpful methods you can use to know that your body is be preparing to ovulate; and therefore, when to try for a baby.
Basal Body Temperature Method
Basal body temperature is your body’s temperature at rest as soon as you wake up in the morning—before you’ve even gotten out of bed. When a woman ovulates, this temperature is ever so slightly elevated. So, by taking your temperature every morning and recording it each day, you can begin to figure out which days of your cycle you’re most likely ovulating each month.
How it Works:
First you’ll need to purchase a basal body thermometer—a very sensitive thermometer that can detect very slight changes in temperature. Most times your basal body temperature only rises by .4 or .8 degrees Fahrenheit when you’re ovulating. The rise in temperature can be a slow climb over a few days, or a sudden jump. While the increase in temperature doesn’t tell you exactly when your egg has been released, almost all women ovulate within three days after the temperature spikes. You’re most fertile (and therefore most likely to get pregnant) two to three days before your temperature hits the highest point, and 12 to 24 hours after ovulation. By the time your temperature has started to go up, the window for conception has closed. So this method is most useful over several months to understand your menstrual cycle and to predict your ovulatory window for the following month.
A word of caution: There are things that can affect your basal body temperature, including drinking alcohol or smoking cigarettes the night before, getting a poor night’s sleep, having a fever, or doing anything in the morning before taking your temperature (including going to the bathroom or using your phone).
Calendar Method
This method should be used for several months for the best accuracy, and involves keeping track of your cycle on a calendar to anticipate your most fertile days in the upcoming months.
How it Works:
Circle the first day of your period (Day 1), then keep track of the total number of days it lasts each month. After recording your cycle for a few months, you’ll be able to estimate your fertile window by doing the following:
- Subtract 18 from the total number of days in your shortest recorded cycle. Use this new number, and count forward that many days from the start of your next period. Draw an X on the calendar.
- Subtract 11 from the total number of days in your longest recorded cycle. Use this new number, and count forward that many days from the start of your next period. Draw an X on the calendar.
The time between the two Xs is the time when you’re likely the most fertile and will ovulate (for a 28-day cycle, ovulation typically occurs somewhere around day 14). While you can certainly go the old fashioned route and use an actual calendar for this method, there are a lot of great ovulation calculator apps that can help with the tracking, and will do the math for you! A recent study showed that using ovulation tracking apps was associated with a higher chance of conceiving.
Cervical Mucus Method
Changes in your cervical mucus is one of the most useful ovulation symptoms that can give you a clue that it’s time to try to get pregnant. Throughout your menstrual cycle, your hormone levels cause changes to the amount and kind of mucus present in the vagina.
Right before, and right after your period, there is usually little to no mucus (described as “dry”). Once the egg starts to mature, mucus increases and is typically cloudy and can be described as “sticky.” Just before ovulation, the mucus becomes wet, clear, and almost slippery (while a bit of a weird comparison, the consistency is often described as “raw egg white”). During this “wet” mucus phase (which usually lasts around four days) is when you’re likely the most fertile.
How it Works:
You’ll need to do a bit of examination of the mucus present in your vagina each day in order to understand the differences throughout your cycle. We know—it sounds a bit weird—but it’s your (amazing) body and a really useful way to know that your body is preparing to release an egg! Sometimes women can also get a sense of their cervical mucous by paying attention when they wipe after using the toilet. It’s helpful to keep a calendar and label the days as “dry,” “sticky” or “wet” to help you keep track of which days of your cycle you’re most fertile (you can easily pair this method with the calendar method described above).
Ovulation Test Kit
Sold in the family planning section near the pregnancy tests, these ovulation tests use your urine to detect a surge in the luteinizing hormone (LH) which triggers ovulation.
How It Works:
Follow the package instructions closely, and use the kit’s recommendation as to what day of your cycle to begin testing (usually a few days before the halfway point of your cycle). For instance, if you have a 28-day cycle, you might begin testing on day 10 or 11. If your cycle is irregular, use the length of your shortest cycle when deciding when to begin testing.
When the test line shows up darker than the control line, you’re about to ovulate. Keep in mind that even if the test line is present but more faint, you’re not ovulating yet. It can be normal to test for several days before the test indicates that you’re ovulating. While more expensive, there are also digital readers that can compare your hormone levels to previous days, making it even easier to clearly detect an LH surge.
While predicting ovulation isn’t an exact science, using these methods (or, even better, a combination of them) can definitely help with accuracy when trying to conceive. And while helpful when trying to get pregnant, these methods are not a reliable form of birth control and shouldn’t be used to prevent a pregnancy.
If you are having difficulty getting pregnant, or are concerned about your fertility, schedule a consultation with your provider or one of our fertility specialists or call 717-544-0107 to learn more about how Penn Fertility Care - Lancaster General Health can help you reach your pregnancy goals.