Cervical mucus: what role does it play in fertility?

More and more women want to take control of their health, including their fertility. However, due to a lack of information and knowledge, practicing so-called natural cycle observation methods can be challenging. Observing and understanding your cycle can be incredibly helpful, whether it’s for managing daily contraception or starting a pregnancy project with your partner.

Focus on cervical mucus and its role in fertility!

What is cervical mucus?

When we talk about the female cycle, we almost automatically think of periods. However, they are far from the only indicator to track your cycle. Cervical mucus (more commonly known as “cervical discharge”) also provides valuable information about the different phases of your cycle. In fact, it is a more precise marker than menstruation (once you know how to observe it).
So, what exactly is it? Cervical mucus – also known by some women as vaginal discharge – is produced by the cervix, more specifically by the cervical crypts located there. It consists largely of water, mixed with immune cells (which defend the body against bacteria, parasites, and viruses) as well as nutrients and enzymes (proteins that affect the body’s biochemical reactions).

In practice, mucus is a substance whose consistency varies throughout the cycle, either preventing or promoting the passage of sperm. Hence its crucial role in fertility.

Did you know? Cervical mucus is made up of more than 90% water!

How does cervical mucus change during the menstrual cycle?

Cervical mucus is the ultimate sign of the ovulatory cycle. It’s both an internal sign (perceptible by the woman) and an external one (visible to the naked eye).
During most of the cycle, the cervix is blocked by thick, plug-like mucus. Cervical mucus flows and is observable throughout the cycle. For 4 to 5 days during the cycle, the mucus becomes more fluid: the beginning and end of this phenomenon mark the fertile window.

And that’s not all! Thanks to Professor Erik Odeblad’s work in 1968, we can distinguish several types of mucus, each with distinct roles and appearances, helping to track the menstrual cycle more precisely.

➡️ During the pre-ovulatory infertile phase, women have very little or no vaginal discharge. They feel dry or slightly moist.

➡️ During the fertile phase, women transition from dry to moist or from moist to wet and start noticing cervical mucus.

➡️ Then comes a progressive increase in sensation: from moist to wet, then very wet, and finally slippery. This phase peaks when a lubricated sensation is felt at the vulva, easily noticeable when wiping. This is the fertility peak.

➡️ The woman then transitions from a high lubrication sensation (the peak day) to dryness or low moisture. This day marks the first day of the luteal phase (more commonly called the post-ovulatory phase starting right after the ovulation peak). This phase lasts 11 to 16 days and ends the day before menstruation.

How can observing cervical mucus help to plan or avoid pregnancy?

Planning or avoiding pregnancy by observing cervical mucus is entirely possible! There are two main methods based on mucus observation and another that adds basal body temperature to these observations.
➡️The Billings Method: the woman observes her sensation at the vulva throughout the day (dry, moist, wet, slippery?). This method relies on the sensation and the adjectives used to describe it.

➡️The FertilityCare Method: the woman observes her cervical mucus when wiping at the toilet (how does the paper feel?). She also checks the color and stretchiness of the mucus between her thumb and index finger. This method relies on touch.

➡️The Sensiplan or sympto-thermal method: this time, basal temperature complements mucus observation, as temperature rises at ovulation. According to the WHO, when perfectly applied, the Sensiplan method is more reliable than the pill! Bonus: this method doesn’t require medication, sparing you potential side effects.

❕ The only downside: all these methods require rigor and learning, which can take more or less time depending on the woman. Also, note that the appearance and consistency of cervical mucus can vary for various reasons and thus mislead your estimated ovulation date.

By observing your cervical mucus, it is possible to identify its different stages and determine your fertile days.

Here are some key figures based on the Pearl Index, a theoretical index showing the percentage of accidental pregnancies per year with rigorous and optimal use of each method:

• Symptothermal: <1%
• Contraceptive pill: 0.3%
• Male condoms: 2%
• Withdrawal: 4%
• Female condoms: 5%

What textures and colors of cervical mucus are normal?

Of course, the texture and color of cervical mucus are different from woman to woman: this is entirely normal! That said, vaginal discharge generally has common characteristics. As mentioned earlier, texture, appearance, thickness, and quantity vary depending on your cycle phase. Your mucus may be liquid, fluid, thick… all of these textures are perfectly normal.
White and liquid discharge is perfectly normal during the cycle, as are translucent, stretchy, or sticky discharge that signals ovulation. Regular observation is key to knowing what is or isn’t normal for you.

Cervical mucus: when should you consult a health professional?

However, certain signs—easily noticeable if you’re observing your cervical mucus—indicate you should see a health professional. They could be symptoms of bacterial vaginosis (an imbalance in your vaginal flora).
➡️White, clumpy discharge, along with itching, may indicate a yeast infection.

➡️Gray discharge with a fishy odor may signal the presence of Gardnerella vaginalis, a bacteria that disrupts the vaginal flora.

➡️Green and foul-smelling discharge can be caused by Trichomonas vaginalis, an STI that goes unnoticed in 15% of women (and 90% of men). It’s not dangerous per se but rather bothersome. Antibiotics are required, and partners should be informed.

➡️Blood in vaginal discharge outside of periods is uncommon. It could be linked to hormonal contraception, HPV, pregnancy, or sometimes an STI like Chlamydia. Though often asymptomatic, Chlamydia can cause complications if untreated. When in doubt, consult a healthcare provider for testing.

➡️Yellow discharge with pelvic pain usually signals Gonorrhea. It’s a medical emergency as it can lead to a fallopian tube infection. Consult your doctor or midwife immediately.

➡️Abundant, off-white, and yellowish discharge may appear if the flora is imbalanced. A probiotic treatment often restores balance.

And of course, if you have any doubt, don’t hesitate to consult your healthcare professional.

What does cervical mucus look like during pregnancy?

During pregnancy, many things change in your body, and cervical mucus is no exception! The most noticeable change: your discharge tends to increase. This is perfectly normal. As long as it remains white and liquid, there’s no need to worry.
Our little advice: get used to observing your cervical mucus to spot any warning signs early (a good tip whether you’re pregnant or not).

Fortunately, during pregnancy, you’re closely monitored by a team of health professionals. If you have any doubts or concerns, don’t hesitate to ask questions during your prenatal check-ups.

❗Watch out for the risk of amniotic fluid leakage: this discharge is usually clear and odorless, like water. Normally, this only happens at the end of pregnancy, but it can occur earlier. Before 37 weeks, go immediately to your maternity emergency unit if you experience fluid loss. After 37 weeks and in the absence of contractions, if the fluid is clear, you have 1 to 2 hours to get to the hospital.

How to improve cervical mucus quality to boost conception?

First and foremost, if you feel your cervical mucus quality is poor and/or you’re having trouble conceiving, don’t hesitate to consult your gynecologist, midwife, or a fertility specialist. They can help identify the cause and support your baby project.
On your side, you can adopt some good habits to boost your fertility, as cervical mucus quality reflects your overall cycle health.

➡️Nutrition: Opt for a varied, balanced, seasonal diet. Buy from local organic producers to maximize your nutritional and micronutritional intake. And don’t forget to stay hydrated!

➡️Exercise: Regular physical activity offers many benefits, and for women trying to conceive, it also helps limit overweight issues, which can disturb hormones and harm fertility.

➡️Sleep: Like exercise, good sleep is beneficial for health and fertility. Aim for more than 8 hours per night in complete darkness (no light pollution).

➡️Disruptors: Tobacco, alcohol, cannabis, drugs… all these disruptors can reduce fertility.

What impact do hormonal contraceptives have on cervical mucus?

The menstrual cycle is mainly regulated by two hormones: estrogens and progesterone. Their production fluctuates throughout the cycle, allowing ovulation and preparing the uterus for a potential embryo. Estrogens dominate the first part of the cycle, and progesterone takes over from ovulation until the next period.
Hormonal contraceptive methods contain synthetic substances that mimic the action of these hormones (estrogens and progesterone) and work together to block ovulation: by receiving constant levels of estrogens and progesterone, the brain (hypothalamus and pituitary gland) no longer sends ovulation-triggering signals to the ovaries.

Additionally, progesterone acts in several ways to prevent pregnancy: it thickens cervical mucus—blocking sperm entry into the uterus and thus fertilization—and it thins the uterine lining, making implantation impossible.

With hormonal contraceptives, there will therefore be no variations in cervical mucus. Since menstrual cycles are paused, there’s no point in looking for changes in color or texture day-to-day.

Learning to observe cervical mucus is therefore very useful if you’re not on hormonal contraception, whether to better understand your menstrual cycle or to take control of your fertility naturally and autonomously.

Want to learn more? Feel free to download the May app, where you’ll find plenty of resources to support and guide you throughout your pregnancy.

Photo: vadymvdrobot

This text was translated from French by an artificial intelligence. The information, advice, and sources it contains comply with French standards and may therefore not apply to your situation. Make sure to complement this reading by visiting the May ES/UK app and consulting the healthcare professionals who are supporting you.