
Is cervical mucus a sign of fertility?

Is cervical mucus a sign of fertility?

Catherine Poslusny | January 31, 2020 | trying to conceive

Cervical mucus (CM) is created by the cervix to serve many purposes, including helping sperm survive in the female reproductive system long enough to reach and fertilize an egg. The vagina and uterus aren’t the most hospitable environment for sperm. That’s why, even though it only takes one to conceive, millions of sperm are released in semen, each one with a single mission: to make it far enough to fertilize an egg (1). CM helps make this journey a little safer by:

  1. Providing shelter for the sperm. Vaginas are slightly acidic, which is a hostile environment for sperm. CM is alkaline, like semen, and it provides a safe environment to protect sperm as they make their way up towards the cervix (2).

  2. Filtering out irregularly-shaped sperm (3). Abnormal sperm, such as those with double tails or weirdly-shaped heads, are less likely to reach and fertilize an egg than normal-shaped sperm (4). CM helps ensure that only the best sperm make it to the egg.

  3. Nurturing sperm. The path to the fallopian tubes is a long trek for a tiny sperm. CM has biochemical nutrients that help sustain the sperm on its journey. This may also help prepare the sperm for the fertilization of the egg (3, 5).

  4. Storing sperm until your body is ready. Fertile cervical mucus can actually hold sperm and keep them alive for up to five days so that they can reach the egg at the right time (3).


Basically, your cervical mucus is like your personal fertility cheerleader. When your CM is fertile, it does everything it can to help the sperm along every step of its path to fertilize an egg.


What are the different types of cervical mucus?

CM isn’t always ready to help an egg get fertilized. In fact, it’s really only super fertile for a few days out of each cycle, as you’ll see below, but if you’re trying to avoid getting pregnant, you’ll have to pay special attention to any CM you produce. Cervical mucus has many faces, and each of them correlates to a specific part of your menstrual cycle. When you learn the pattern, you can start to use CM observations to help determine whether you’re fertile or not on any given day. 




The first few days after your period ends, you may not have a lot happening, CM-wise, around your vulva or the opening of your vagina. You may notice some moisture on your fingers when you swipe to check for CM, but if the moisture on your fingers evaporates quickly, it is vaginal moisture, not cervical mucus. You are most likely not fertile on these days, and the lack of CM makes it hard for any sperm to survive in your body until you ovulate (6).



This is the first noticeable CM of your cycle. Sticky CM may look like the glue or paste that you used in arts and crafts as a kid. It may be white or yellowish and maybe even a little gummy or springy. On these days, your CM may seem more like a solid than a liquid. Sticky CM signals the beginning of your fertile period. It may not seem like much, but it may just be enough to help a sperm survive until your cervix starts producing the really fertile stuff (6).




As you progress through your cycle, your estrogen levels will keep rising, causing the water content of your cervical mucus to increase (6). Creamy CM is basically sticky CM with a little added moisture. It may look milky or cloudy on your finger, kind of like cream or hand lotion. 


Egg white

Egg white cervical mucus is clear, slippery, and pretty stretchy, like the consistency of egg whites. This CM is considered very fertile because it has the perfect texture and pH for protecting sperm (7). Egg white CM may keep sperm alive for up to five days inside your body (5).




Right before ovulation, your CM may become even more watery. This is the kind of CM that can slide right out of your vagina and into the toilet (or onto your underwear) with a sensation similar to menstrual bleeding. At this stage, your CM has the highest water content and is the most fertile (6).


Ovulation and Menstruation

The fertile CM will take you up to the day of ovulation, after which estrogen levels will drop, and so will the moisture content of your CM. You will go back to dry or sticky CM until your menstruation starts again. You may or may not have CM during your period, but it is usually masked by the presence of menstrual blood (6).


Note: Don’t worry if your CM doesn’t fit neatly into the above classifications. Everyone’s cervical mucus is different, and some people even experience multiple types of CM in a single day (8). Read more about what to do if your cervical mucus doesn’t match the standard categories.


What does my cervical mucus tell me?

Tracking your CM is a helpful way to understand where you are in your menstrual cycle. By learning what the types of CM look like for your body, you can determine when you’re in your fertile window (the day that you ovulate and the 5 days preceding it) (9). When you understand what your CM is telling you, you can make informed decisions on when and how to have sex, whether you’re trying to conceive or trying to avoid getting pregnant. 


If you’re TTC, having sex on days that you have fertile cervical mucus can help maximize your chances of conception (10). Remember, the higher the water content of your CM, the more fertile it is. Read more on how to track cervical mucus to get pregnant

If you’re trying to avoid getting pregnant, you’ll want to avoid having penis-in-vagina sex or use a barrier method of contraception on your fertile days. Also, you shouldn’t rely on cervical mucus tracking as your only method of birth control until you’ve consistently tracked your daily CM for at least three cycles (11) and met with a specialist for individual coaching and review of your charts. Check out the 4 Rules of Charting for Birth Control for more details and read Taking Charge of Your Fertility by Toni Weschler.


Monitoring your CM changes throughout your menstrual cycle can give you insight into your fertility. You can start to see your body preparing for a possible pregnancy each month and learn how to tell the difference between fertile and infertile days. Consistent daily CM tracking is the key to noticing and understanding these patterns in your body. 


Photo by Huha Inc. on Unsplash


  1. https://www.plannedparenthood.org/learn/teens/ask-experts/how-much-sperm-is-supposed-to-come-out-when-you-ejaculate
  3. https://www.ajog.org/article/S0002-9378(11)90559-6/pdf
  4. https://www.mayoclinic.org/diseases-conditions/male-infertility/expert-answers/sperm-morphology/faq-20057760
  5. https://www.babymed.com/how-long-do-sperm-survive
  6. Weschler, Toni. (2015). Taking Charge of Your Fertility: The definitive Guide to Natural Birth Control, Pregnancy Achievement, and Reproductive Health.
  7. https://americanpregnancy.org/getting-pregnant/cervical-mucus/
  8. https://www.med.unc.edu/timetoconceive/study-participant-resources/cervical-mucus-testing-information/ 
  9. https://www.acog.org/Clinical-Guidance-and-Publications/Committee-Opinions/Committee-on-Gynecologic-Practice/Prepregnancy-Counseling?IsMobileSet=false#11
  11. https://www.plannedparenthood.org/learn/birth-control/fertility-awareness/whats-cervical-mucus-method-fams