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Understanding Cervical Mucus and the Fertility Window

What’s the deal with cervical mucus? If you’re a guy, cervical mucus might not be something you are familiar with, but it could actually be the magic ingredient that helps you on your fertility journey. Here we’ll bring you up to speed on all things cervical mucus, so you can be a proactive, supportive and informed partner.


What is Cervical Mucus?


Cervical mucus is a fluid produced by the cervix. The cervix sits at the top of the vaginal canal and protects the opening to the uterus. It’s made of a bunch of incredible things produced by the body including proteins, enzymes and fatty acids which are combined with an insoluble gel.

Cervical mucus is slightly different to the ‘wetness’ that women experience during arousal. When aroused the Bartholin’s glands inside the side of the vagina produce a liquid to make sex safer and more enjoyable. However, the mucus produced by the cervix is happening all the time – whether you’re getting frisky or not. Hormonal changes throughout the menstrual cycle change the consistency of cervical mucus and in your fertile window, it plays a very important role.


What is the fertile window?


The fertile window refers to the timeframe where pregnancy can occur – that’s right, despite what your school sex education sessions taught you – it’s not really possible to get pregnant every time you have sex.

For conception to take place the egg and the sperm need to be in the same place at the same time. A woman generally ovulates once a month (although cycles can vary from person to person) which means each month you have a new opportunity to make a baby. After ovulation, the egg only survives for around 24 hours before it will die (if not fertilised). However, sperm cells can live in the female body for up to 5 days, so technically anytime you have sex in the few days leading up to ovulation – and one day after – is the fertile window. You can learn more about the best time to have sex if you want to get pregnant here.


Fertility and Cervical Mucus


Cervical mucus plays an essential role in the conception and there are a few ways that it helps you on your fertility journey.

Cervical mucus indicates the fertile window

As mentioned earlier, the consistency of cervical mucus changes at certain points in the menstrual cycle. On some days it can be dry, on other days it can be sticky, and in the lead-up to ovulation, it becomes very wet and slippery – similar to the consistency of raw egg white. This is the body’s way of telling a woman they are nearing, or in, their fertile window – it’s nature’s own ovulation predictor kit.

For couples trying to get pregnant, tracking the consistency of the cervical mucus throughout the month can be really helpful for pinpointing the best time to have sex. Unlike menstrual cycle apps that simply use an algorithm to ‘predict’ the next ovulation based on previous data, taking note of your cervical mucus will give you a live update as to where your body is at. Tracking your cervical mucus alongside other key indicators of fertility – including basal body temperature and the position of your cervix is known as the Fertility Awareness Method and following this can help you improve your chances of conceiving naturally.

Sperm Super Highway

But cervical mucus is not only helpful for predicting ovulation – it’s actually a huge help for your sperm cells too! For parts of the menstrual cycle, cervical mucus is dry or sticky – which actually acts as a barrier to sperm. However, during the fertile window, the slippery cervical mucus is there to give your swimmers a helping hand. The thinner, wetter consistency of the mucus acts a bit like a sperm super highway as it’s easy for the sperm cells to swim through, making their trip up to the cervix, uterus and fallopian tubes faster.

The cervical mucus during the fertile window also helps to keep sperm alive. Vaginal canals are usually not very hospitable to sperm cells and for most of the month, the environment is fairly acidic – which will kill your swimmers. However, during the fertile window, the cervical mucus becomes more alkaline, so it’s much friendlier to sperm. The cervical mucus, along with the semen, nourishes the sperm cells so they can stay alive for longer – so even swimmers that turn up a few days before ovulation have a fighting chance of making it to the egg!


Hostile Cervical Mucus


Whilst cervical mucus is generally there to support your fertility journey – there can be occasions where it has the opposite effect – even during the fertile window. These issues can vary but collectively they are known as ‘hostile mucus’ and often occur alongside other female factor fertility issues.

Hostile mucus can manifest itself in many ways – it might be too acidic due to an infection or it could be too dry due to a hormonal imbalance. It’s also possible that an immune response has caused the cervical mucus to contain inflammatory cells, which can attack and kill the sperm, even around ovulation. There are various treatments for hostile cervical mucus and assisted fertility approaches that can help you get pregnant if that’s something you’re struggling with.

Hostile mucus aside, cervical mucus is one of the biggest allies in your journey to parenthood – so get tracking!

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More to explore


Wearing tight pants and underwear

Studies show that men who wear looser underwear have higher sperm concentration and total sperm count compared to men who wear tighter underwear. So, lose the tight clothes and wear something loose to give your testicles some air.

CONCLUSION: learn more about how heat can affect sperm quality here.


Besides higher mortality rate and various diseases, stress is associated with low sperm quality. Stress is known to be associated with lower testosterone levels and oxidative stress with both playing an essential role in producing and maintaining healthy sperm cells.

CONCLUSION: If you feel stressed, we recommend you get some help so you can have a balanced mental health. For a stress management guide, download the ExSeed app for free and start your personalized action plan today.

Physical activity

Scientific studies show that men who are physically active have better semen parameters than men who are inactive. Fertility specialists also state that regular physical activity has beneficial impact on sperm fertility parameters and such a lifestyle can enhance the fertility status of men.

Prioritizing exercise can help improve your overall health and result in healthy, fast swimming sperm cells that have good chances of fertilizing an egg.

CONCLUSION: Try incorporating exercise in your weekly schedule to you ensure exercising at least twice weekly. We recommend a combination of cardio training and strength exercise. Read more about exercise and male fertility on our blog.


Fast Food
Processed foods damage the health of sperm-producing cells and cause oxidative stress, which lead to poorer sperm quality. Heavy consumption of junk food (every week) can increase the likelihood of infertility since men who consume vast amounts of unhealthy food are at risk of having poor sperm quality. Besides harming your fertility, junk food enlarges your waistline, harms your cardiovascular system, kidneys, and more.

Eating more fruit and vegetables can increase your sperm concentration and motility. It’s important that you consume a healthy diet filled with antioxidants and that you eat vegetables every day. Foods such as apricots and red bell peppers are high in vitamin A, which improves male fertility by nurturing healthier sperm. Men who are deficient in this vitamin tend to have slow and sluggish sperm.

Sugary snacks/beverages: several times a week Excessive consumption of high sugar items can lead to oxidative stress, which negatively impacts testosterone levels and sperm motility. Sugary snacks and beverages are also highly associated with obesity and low fertility.
CONCLUSION: To boost sperm quality, stay away from fast food, processed food, and sugary snacks or beverages. You need to implement a healthy prudent diet filled with necessary superfoods needed for good sperm production. Check out our guide to Male Fertility Superfoods. For personalized guidance and support on how you can start improving your sperm health, check out the Bootcamp.


Direct heat can inhibit optimal sperm production and cause Sperm DNA damage. Sperm cells like environments that are a couple of degrees lower than body temperature. Avoid overheating from warm blankets, seat warmers, heat from your laptop, hot showers, and saunas.

Cigarette smoking

The exposure to tobacco smoke has significant negative effects on semen quality. The damage of cigarettes and nicotine of course depends on how many cigarettes you smoke per day and for how long, but even low usage (up to 10 cigarettes / day) can inhibit healthy sperm production.  

CONCLUSION: Stay as far away from cigarette smoking as possible if you care about your general health and your fertility. Read more here.

Cell phone

When you have your cell phone in your front pocket, your testicles are exposed to electromagnetic radiation, which studies have shown to damage the sperm cells. Put your phone in the back pocket of your pants or in your jacket pocket.


There is a clear association between obesity and reduced sperm quality. At least part of the reason for this is that obese men may have abnormal reproductive hormonal profiles, which can impair sperm production and lead to infertility. 

A BMI higher than 30 can lead to several processes in the body (overheating, increase in oxidative stress in the testes, sperm DNA damage, erectile dysfunction) that can have a negative impact on male fertility. This can result in problems when trying to conceive.  

CONCLUSION: BMI is one of the risk factors that influence semen quality and, for example, sperm motility.  


A beer or glass of wine now and then do not really harm sperm quality. But excess alcohol drinking (more than 20 units per week) can reduce the production of normally formed sperm needed for a successful pregnancy.

CONCLUSION: If you want to stay safe, stay under 14 units of alcohol per week. For more information on how alcohol can affect male fertility, take a look at our blog: “Alcohol and Sperm Quality”.


Studies show that women younger than 35 and men younger than 40 have a better chance of getting pregnant. Men can produce sperm cells almost through their entire life, but the sperm cell DNA is more fragile and prone to damage after the age of 40.

As men age, their testes tend to get smaller and softer resulting in a decline in sperm quality and production. These changes are partly because of an age-related decrease in testosterone level, which plays a very important role in sperm

production. Higher male age (>40 years) is not only associated with a decline in sperm production but also with increased sperm DNA fragmentation and worsened morphology (shape) and motility (movement). These negative effects make the sperm cells less qualified for egg fertilization.

CONCLUSION: with an age under 40, you shouldn’t have to worry much about age as a factor in itself. However, studies have shown a slow decline after the age of 30-35 years

and if you are above 40 years of age, your sperm quality can be affected due to increased sperm DNA damage resulting in a decrease of sperm motility and concentration. Remember that you cannot evaluate the quality of a sperm sample by just looking at it – this requires a sperm analysis.