Discover Your Key Fertility Sign: Cervical Mucus
Oh, cervical mucus! That wonderful nectar of fertility!
Originally written for and posted on Vira.com
Illustration by Pear Viracha
These are just some of the things I use to demonstrate what cervical mucus looks like when I teach fertility awareness.
Flax seed gel.
Lube.
Lotion.
Liquid school glue.
Coconut oil.
Glue stick.
Oh, cervical mucus! That wonderful nectar of fertility! When it’s around, you can catch it hanging out at your perineum or on your toilet paper (that is, if you haven’t peed or pooped it away.)
Have you seen it before? Some people tell me they’ve noticed it but didn’t take much note while others have told me they confused their cervical mucus with a yeast infection or an STI. The truth is, cervical mucus is a normal, healthy, and essential part of the menstrual cycle.
What is cervical mucus
Cervical mucus is a hydrogel that contains mucus molecules, water, enzymes, protein chains, and biochemical compounds including sodium, chloride, and potassium.¹ Sometimes called cervical fluid, it comes from the cervix (hence the name).
Your cervix is the gateway between the vagina and the uterus. It works as a biological valve that is either open or closed depending on where you are in your cycle.² Insert your longest finger into your vagina while squatting and you’ll meet your cervix!
Cervical mucus can be stretchy like raw egg whites or sticky like glue from a glue stick and anything in between. It can also be clear, cloudy, cloudy-clear, red, pink, or even pale yellow. Sometimes you can’t even pick it up because the mucus is so high in water content (it can rise as high as 99 percent!³) but you’ll still know it’s there because it creates a slippery sensation when you wipe. Have you ever hit your elbow on the back seat of the toilet after wiping? Yeah, that’s it. This is all normal.
It’s also normal to only see your cervical mucus sometimes.
The typical pattern for a healthy menstrual cycle will experience some variation of the following. The first day of the menstrual cycle starts with menstruation. After menstruation there may be some dry days where there is no observable cervical mucus at the vulva (except in shorter cycles). Eventually there is a change and cervical mucus is present. In a healthy cycle, you will see the cervical mucus for an average of 5 days before ovulation.⁴ Once ovulation occurs, you’ll notice a shift back to dry days until your period comes and the whole thing starts again. Other patterns are also possible especially in times of stress or in cycle changes like discontinuing hormonal contraception, postpartum, or perimenopause.
Photo from the Justisse Guidebook
Why is cervical mucus important
Did you know that ovulation only happens on one day and once the egg is released from the ovary, it only has 12 to 24 hours to be fertilized?⁵ It often seems impossible humans can get pregnant at all!
The reason we’re fertile for longer than 24 hours is because cervical mucus appears before ovulation and extends that small window of fertility to approximately 6 days of your cycle.⁶ This is because cervical mucus can keep sperm alive for up to 5 days.⁷ Outside of this fertile window, pregnancy is not possible.
Let me explain to you how this works.
The cervix is like a hotel for sperm. Sometimes the hotel is open and sometimes it’s closed depending on your ovarian hormones and cervical mucus production.
As your ovaries produce estrogen and your body prepares for ovulation, your cervix responds by producing estrogenic (or E-Type) cervical mucus.⁸ This is the cervical mucus that is visible on your vulva and shows up on your toilet paper letting you know you’re fertile and the sperm hotel is open. Imagine the cervical mucus is like the red carpet that’s just rolled out of the vagina welcoming the sperm. It creates an alkaline pH in the vagina making it sperm-friendly. The pH of semen is between 7.2 and 8.4 which is about the same pH as your cervical mucus with an average of 7.⁹ It also forms channels within the cervix making it easy for sperm to swim through.¹⁰ Not for every sperm though because there’s a very picky security guard choosing who to let in. Qualities of cervical mucus prevent abnormal sperm from getting through.¹¹ The ones that do get through are prepared to fertilize the egg through a process called capacitation that happens in the cervical mucus.¹² Once the sperm reach the cervix, they get to check into the sperm hotel for up to 5 days waiting for ovulation to occur.
After ovulation, your ovaries produce hormone progesterone which suppresses estrogenic cervical mucus production.¹³ Progesterone makes gestagenic (or G-Type) cervical mucus which creates a mucus plug inside your cervical canal that acts as a physical barrier between your vagina and your uterus.¹⁴ The pH of the vagina returns to its sperm-hostile acidic state and hotel is closed. Sperm can’t penetrate this cervical plug and instead they die hanging out in the lobby.
Photo from the Justisse Guidebook
G-Type Gestagenic Mucus
AKA The Sperm Hotel is CLOSED
Creates a cervical plug
Acidic pH that is not favourable to sperm survival
Acts as a physical barrier
Sperm die within minutes after ejaculation
No cervical mucus is visible
E-Type Estrogenic Mucus
AKA The Sperm Hotel is OPEN
Forms channels that allow sperm to reach the cervix
Alkaline PH making it sperm-friendly
Capacitates and nourishes sperm
Allows sperm to live in the cervix for up to 5 days
Cervical mucus is visible at the vulva
Mythbuster: All cervical mucus is fertile
All cervical mucus is fertile! A common misconception is that there is fertile cervical mucus and non-fertile cervical mucus or that some cervical mucus is more fertile than others.
All types of cervical mucus & all amounts of cervical mucus are fertile!
It’s simple. When cervical mucus is visible, the cervix is open and ovulation is imminent. It’s like calling someone more pregnant. The person is either pregnant or not. They can’t be “more pregnant”. They can, however, be closer to their due date and cervical mucus works in a similar way.
The closer you are to ovulation, the more likely you will see peak-type cervical mucus. Some people start their fertile window immediately with peak-type mucus while others start to see non-peak mucus first. Sperm can survive for several days in non-peak mucus and wait for ovulation to occur¹⁵.
Peak type mucus is any mucus that is clear or stretchy or lubricative (comes with a slippery sensation).
Non-peak mucus is any mucus that is not clear or stretchy or lubricative. Instead it might be sticky or tacky in consistency or cloudy (white) or yellow in colour.
“So then why bother to distinguish between peak and non-peak mucus?” you might ask.
Because that’s how we can:
Confirm ovulation
Optimize chances of conception
Achieve the high efficacy of fertility awareness-based methods, and monitor our menstrual cycle and overall health.
Why check for cervical mucus
With the knowledge you gain from checking your cervical mucus, you can prevent or achieve pregnancy without medical intervention and gain insight into your reproductive and overall health.
According to one study, only 12.7% of people seeking fertility treatment can accurately identify their fertile window.¹⁶ Cervical mucus is hands down the most important sign of fertility. Checking your cervical mucus can allow you to identify when you’ve entered your fertile time and when you’ve exited it (unlike the second most important sign of fertility, basal body temperature, which can only confirm you’ve exited your window). Knowing when you’re fertile, you can optimize your chances of conception.
You can also use this information in the opposite way:
To prevent pregnancy
Identifying your fertile window
Abstaining from intercourse during this time is the basis of the Fertility Awareness Method for birth control.
When used correctly, it’s over 99% effective¹⁷ which makes it just as effective as the pill but without any of the side effects. Some people also choose to be fertility aware and then decide to use a barrier method during their days of fertility. In this case, they are relying on the effectiveness of the barrier method knowing that pregnancy is possible at this time.
And if that wasn’t enough, the menstrual cycle is the fifth vital sign so understanding your variation of normal can help you become an advocate for your own reproductive and overall health. Mapping your cervical mucus observations on a chart can be like a monthly report card that gives you insight into your hormonal balance, stress levels, and underlying medical conditions.
Once you start paying attention to your cervical mucus, which I also proudly refer to as a Menstruator-Only-Super-Awesome-Mindfulness practice, the benefits are truly endless.
So, have you checked your cervical mucus today?
References
1 Odeblad, Erik. "The discovery of different types of cervical mucus and the Billings Ovulation Method." Bulletin of the Natural Family Planning Council of Victoria 21, no. 3 (1994): 4; Klaus, Hanna. "Natural Family Planning - Is it Scientific? Is it Effective?" Newman Lecture Series 1 (2002): 6.
2 Hilgers, Thomas W. (2004). The Medical & Surgical Practice of NaPro Technology. Omaha, NE: Pope Paul VI Institute Press, 185-186.
3 Pommerenke, W.T. “Cyclic changes in the physical and chemical properties of cervical mucus.” American Journal of Obstetrics and Gynecology 52, no. 6 (1946): 1023-1031.
4 Odeblad, Erik. "The discovery of different types of cervical mucus and the Billings Ovulation Method." Bulletin of the Natural Family Planning Council of Victoria 21, no. 3 (1994): 3-31; Hilgers, Thomas W. (2004). The Medical & Surgical Practice of NaPro Technology. Omaha, NE: Pope Paul VI Institute Press, 203-205.
5 Depares, J., R.E. Ryder, S.M. Walker, M.F. Scanlon, and C.M. Norman. “Ovarian ultrasonography highlights precision of symptoms of ovulation as markers of ovulation.” British Medical Journal (Clinical Research Ed.) 292, no. 6536 (1986): 1562.
6 Fehring, Richard J., Mary Schneider, and Kathleen Raviele. “Variability in the phases of the menstrual cycle.” Journal of Obstetric, Gynecologic, & Neonatal Nursing 35, no 3 (2006): 376-384.
7 Stein, I.R., and Melvin R. Cohen. “Sperm survival at estimated ovulation time: prognostic significance.” Fertility and Obstetric Investigation 6, no. 3-4 (1975): 206-214.
8 Odeblad, Erik. "The discovery of different types of cervical mucus and the Billings Ovulation Method." Bulletin of the Natural Family Planning Council of Victoria 21, no. 3 (1994): 8-13; Moghissi, Kamran S. “The function of the cervix in fertility.” Fertility and Sterility 23, no. 4 (1972): 295-306.
9 Haugen, T.B., and T. Grotmol. “pH of human semen.” International Journal of Andrology 21, no. 2 (1998): 105-108; Eggert-Kruse, Waltraud, Andreas Köhler, Gerhard Rohr, and Benno Runnebaum. “The pH as an important determinant of sperm-mucus interaction.” Fertility and Sterility 59, no. 3 (1993): 617-628; Stein, Irving F., and Melvin R. Cohen. “Sperm survival at estimated ovulation time: prognostic significance.” Fertility and Sterility I, no 2 (1950): 169-175; Ahlgren, Mats. “Sperm transport to and survival in the human Fallopian tube.” Gynecological and Obstetric Investigation 6, no. 3-4 (1975): 206-214.
10 Menarguez, Mikaela, Erik Odeblad, and Helvia Temprano. “Recent Research in Cervical Secretion: Some Biophysical Aspects.” Sveikatos Mokslai/Health Sciences 21, no. 3 (75) (2011): 55-60.
11 Odeblad, E. A. Ingelman-Sundberg, L. Hallstrom, A. Hoglund, U. Leppanen, K. Lisspers, E. Perenyi, K. Rudolfsson-Asberg, K. Sahlin, and C. Lindstrom-Sjorgren. “The biophysical properties of cervical-vaginal secretions.” International Review of Natural Family Planning 7, no. 1 (1983): 1-56
12 Lambert, Hovey, James W. Overstreet, Patricio Morales, Frederick W. Hanson, and Ryuzo Yanagimachi. “Sperm capacitation in the human female reproductive tract.” Fertility and Sterility 43, no. 2 (1985): 325-327.
13 Odeblad, Erik. "The discovery of different types of cervical mucus and the Billings Ovulation Method." Bulletin of the Natural Family Planning Council of Victoria 21, no. 3 (1994): 13.
14 Odeblad, Erik. “The functional structure of human cervical mucus.” Acta Obstetrica et Gynecologia Scandinavica 47, no. SI (1968): 57-79.
15 Odeblad, E. “Investigation on the physiological basis for fertility awareness method.” Bulletin of the Ovulation Method Research and Reference Centre of Australia 29, no. 1 (2002): 2-11.
16 Mahey, R., Gupta, M., Kandpal, S., Malhotra, N., Vanamail, P., Singh, N., & Kriplani, A. “Fertility awareness and knowledge among Indian women attending an infertility clinic: a cross-sectional study.” BMC women's health 18, no. 1 (2018): 177.
17 Frank-Herrmann, J. Heil, C. Gnoth, E. Toledo, S. Baur, C. Pyper, E. Jenetzky, T. Strowitzki, G. Freundl. “The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple's sexual behaviour during the fertile time: a prospective longitudinal study.” Human Reproduction 22, no. 5, (2007).