When you’re trying to conceive, one of the most important things you can do to maximize your chances of getting pregnant is chart your fertility signs. Your body gives you different clues throughout your menstrual cycles to let you know when you’re at your most fertile. By learning to read these clues, you can actively plan to have sex when you’re most likely to get pregnant. (The best part? It’s almost completely free to do!) Read on to learn how charting your cycles can help you optimize your fertility.
During each menstrual cycle, there are typically 6 days that you have the potential to get pregnant (1). There are a couple reasons for this. First, after an egg is released from the ovary during ovulation, it will only survive for 12 to 24 hours (2). It needs to get fertilized within that time frame for you to get pregnant. Second, sperm can survive in fertile cervical mucus for up to 5 days (2). This means that having sex in the 5 days before or on the day of ovulation may result in a pregnancy — this is called your fertile window.
The American Society for Reproductive Medicine recommends having unprotected sex every day or every other day during your fertile window to maximize your chances of conception (3). Unfortunately, women don’t automatically know which day they ovulate each month. That’s where charting fertility signs comes in.
Charting involves daily monitoring of your fertility signs to determine when you ovulate each cycle. The main things to track when charting are cervical mucus (CM), basal body temperature (BBT), menstrual bleeding, and when you have sex (4). Some people also track cervical position or use at-home hormone tests (called ovulation predictor kits, or OPKs) to help them figure out when ovulation is about to occur.
Charting is free (minus the cost of a basal body temperature thermometer, which shouldn’t be too expensive), and it only takes a few minutes a day. Plus, it gives you the opportunity to learn more about your body and work with your natural cycles to increase your chances of getting pregnant (5).
You may be able to use your basal body temperature to confirm ovulation after it happens (6). Also known as your waking temperature, BBT is your body’s temperature when you’re at rest (4). BBT tracking has been used for generations to help them avoid or achieve pregnancy.
After you ovulate, your body starts producing more progesterone to prepare for a potential pregnancy. This rise in progesterone also causes a subtle rise in BBT that lasts until the start of your next period (4). During the first part of the menstrual cycle (the follicular phase), BBT generally stays between 97.0 and 98.0°F. About 1 day before ovulation, BBT may dip slightly. Then, the day after ovulation, BBT rises by about 0.5 to 1.0°F and stays there until you either start or are about to start your next period (7).
To track your BBT, you’ll need to get a basal body temperature thermometer and keep it right next to your bed. Then, take your temperature every morning when you first wake up, before you get out of bed, check your phone, take a drink of water, or do anything else (8).
After a few cycles, you may start to see a biphasic pattern. This means that your BBT has two phases — one with lower temperatures during the first part of your cycle (the follicular phase) and one with higher temperatures after you ovulate (the luteal phase). Graphing your temperature each day can make it easier to spot your BBT patterns.
The downside to BBT tracking is that your temperature shift only happens after you ovulate. So, when you notice the rise in temperature, it’s probably already too late in your cycle to conceive (9). Also, many factors may affect your BBT readings and make it hard to see your temperature shift, such as fever or sickness, stress, shift work, drinking alcohol the night before, waking up during the night, and oversleeping (9).
For some, tracking BBT may be difficult or impractical. If you’re still interested in using temperature to help you conceive, check out the Priya Fertility System, an intravaginal sensor and mobile app that measures continuous core body temperature (CCBT) to detect the subtle temperature patterns that occur 2-4 days before ovulation and maximize your chances of getting pregnant.
Your cervical mucus plays a huge role in your fertility. Vaginas are naturally slightly acidic, which helps protect against infection but also creates a hostile environment for sperm. Cervical mucus (CM), on the other hand, is alkaline, just like semen. As you get closer to ovulation, your body produces more fertile CM to help protect and nourish sperm as they travel towards the egg (10).
Throughout your cycle, your CM will likely go through a series of transformations. These changes look different for everyone, so part of fertility charting will mean learning to recognize what each CM phase looks like for you. To check your CM, use a folded piece of toilet paper or a clean finger to wipe across the opening of your vagina from front to back (11, 12, 13)
Generally, right after your period, your body won’t produce much CM at all. As you get closer to ovulation, you’ll notice your CM increase both in volume and water content as your estrogen levels get higher (4). First, it will be sticky or pasty, then creamy, then slippery and stretchy (this is referred to as egg white cervical mucus), then watery. After you ovulate, your CM will start to dry out again (12, 13).
Both egg white CM and watery CM indicate that you’re close to ovulation. This is the CM that will help keep sperm alive long enough to fertilize the egg. Like BBT, CM should be tracked for a few cycles for you to be able to recognize the patterns that happen around the time you ovulate (4, 12, 13).
These are the general patterns that CM tends to follow, but the descriptors may not match what you see, and that’s ok. Everyone’s body is different, so some people might not see watery or even egg white CM, or they might skip from sticky to egg white without seeing creamy (13). As long as you’re consistent with tracking how your cervical mucus changes throughout your cycle, that’s the important part to understanding your cycle.
Still have questions about tracking your CM? Check out this blog post that answers the 5 top questions about cervical mucus patterns.
Though BBT and cervical mucus are the 2 main fertility signs used in charting, they’re not the only ones that can help you tell when you’re approaching ovulation. The position of your cervix can also give you some insight as to where you are in your menstrual cycle.
Your cervix is the lower part of your uterus and protrudes into the upper part of your vagina with a small opening called the os (14). At the start of each cycle, your cervix sits lower in your vagina. At this time, the os is closed and feels firm, like the tip of your nose. As you get closer to ovulation and your estrogen levels rise, the os starts opening up to allow sperm through. It also gets softer and rises higher in your vagina (15).
Ovulation predictor kits may be used alongside cycle tracking to help you find your fertile window. These tests work by measuring the amount of luteinizing hormone (LH) in your urine. They’re made to detect the surge of LH that happens anywhere between 36 to 40 hours before ovulation (16, 17). However, it takes a while for LH to build up to the point of being detected in urine, so OPKs typically won’t recognize your LH surge until 12 to 24 hours before ovulation (17).
OPKs do come with some drawbacks. Not only do you have to keep buying new tests each month, but OPKs may not even detect your LH surge in time for you to have sex while you’re at your most fertile (typically the day or 2 before you ovulate) (18). By the time an OPK detects your LH surge, you may have already missed most of your fertile window (19). Plus, you could even miss your fertile window entirely with OPKs alone.
When you’re first starting out with fertility charting, you may want to consider talking to a fertility awareness medical professional who can help you understand how to read your chart. Additionally, connecting with other women who are charting — such as through the Community tab on the Kindara App — can be a great source of information and encouragement. There’s a bit of a learning curve when it comes to fertility charting, but the effort is well worth it to be able to read your body’s signs and predict when you’re most fertile.
About the author
Catherine Poslusny is a writer and content marketing strategist based out of Norman, Oklahoma. She's written for healthcare companies since 2016, and she's most passionate about her work in women’s health, fertility, and reproductive rights. You can find her at catherinerosewrites.com.
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