Menstrual cups are a popular period care choice however, for a comfortable and leak-free experience, understanding one's cervical position is crucial.
In this blog, we will explore the "knuckle test rule" which is a simple and effective method to measure cervical position and why knowing your cervical position matters for menstrual cup users.
Understanding Cervical Position
Think of your vagina like a tube, with the cervix positioned at the end opposite your vaginal opening. The cervix is the lower part of the uterus that extends into the vaginal canal.
Cervical position is described in terms of height of the cervix in the vaginal canal. Some people naturally have a higher or lower cervix and and the position of the cervix can also change during the menstrual cycle due to hormonal fluctuations and fertility.
The higher your cervix is, the further away it will be from your vaginal opening and the lower your cervix, the closer it will be to the vaginal opening. Having a high or low cervix doesn’t mean there’s anything wrong with you but it’s an important factor to consider when choosing a menstrual cup.
When to Check your Cervical Position
Perform the cervical position test at least three times times during your menstrual cycle.
Some people have a fairly consistent cervical position throughout their cycle whist other people find it moves around quite considerable during menstruation. For people that have a cervix which is on the move, they typically find their cervix will sit lower at the start of their cycle (when the uterus or womb is full and heavy) and mover higher towards the end of their cycle (when the lining of the uterus sheds and the uterus size contracts back to its original size). See our blog on How the uterus changes size throughout the menstrual cycle - it's fascinating to see the size changes!
If your cervical position changes a bit during your cycle you may wish to consider have two different lengthy cups for different stages of your cycle.
Measuring Cervical Position Using the Knuckle Test Rule
The knuckle test rule is a practical way to determine the location of your cervix in relation to the bends or 'knuckles' on your index finger.
To perform this test, you will need to follow these steps:
- Wash your hands thoroughly with soap and warm water.
- Find a comfortable position: Either standing with one leg raised, squatting, or sitting on the toilet.
- Insert a clean index finger into the vaginal canal until you feel your cervix. Your cervix is shaped like a doughnut and described as feeling like the tip of your nose.
- Take note of the height of the cervix in relation to the how far you can insert your finger into the vaginal canal. An easy way to do this is to measure which 'knuckle' of the index finger is near the vaginal opening when you feel the cervix.
Cervical Positions
The cervical position can be categorised into three main types:
- High Cervix: If you have to reach your finger all the way into the vaginal canal to feel your cervix or if you can't feel it all, your cervix is considered high. This means your vaginal canal is long and that your menstrual cup will likely sit higher up in your vaginal canal during use and may be more difficult to remove. You may like to choose a menstrual cup specifically for a high cervix, particularly if you are new to using menstrual cups. Cups suitable for a high cervix typically have a longer body and/or stem, so that the base of the cup sits within reach for your fingers. See our list of menstrual cups for a high cervix. If you are an exiting cup user who has come across our blog and are struggling to remove your menstrual cup, get some helpful tips from our blog on what to do if your menstrual cup is stuck.
- Medium Cervix: If you can reach your cervix with moderate ease and you can feel the cervix when your finger is roughly half way inserted into the vaginal canal, it is positioned at a medium height. In this case, your menstrual cup will generally sit at a middle position in your vaginal canal.
- Low Cervix: If you can easily touch your cervix or it feels very close to the vaginal opening, your cervix is considered low. Your vaginal canal is short and your menstrual cup will likely sit lower in your vaginal canal. If you have a particularly low cervix or prolapse, your cup may even protrude out of the vaginal opening or be expelled during use. You may like to choose a menstrual cup designed specifically for a low cervix to avoid having the menstrual cup sitting partially outside the vaginal opening during use. Low cervix menstrual cups tend to have a shorter body, may be more rounded (rather than cone-shaped) and may have a shorter stem or be designed without a stem. See our list of best menstrual cups for a low cervix. Some people with a low cervix often find menstrual discs are better suited to their anatomy than menstrual cups, so discs may be another option to explore.
Accurately Measuring your Cervical Position
Whilst the 'knuckle test rule' is a great way to quickly find out your cervical position, it may not be super accurate, particularly if you have short or long fingers.
A more precise way to measure your cervical position is to take note of how far you can insert your finger into the vagina before your can feel your cervix. Then place your finger alongside a ruler to get a more accurate measurement of the vaginal canal length.
You can then choose a cup that has a length appropriate for the height of your cervix. Once you have this information you can use our menstrual cup comparison chart to sort menstrual cups based on their overall length and find one that's the perfect fit for you.
Images: JuJu
Why Does Cervical Position Matter for Menstrual Cup Users?
Understanding your cervical position is essential for menstrual cup users because it directly impacts the selection and placement of the cup for a comfortable and leak-free period.
Let's delve into the reasons why cervical position matters:
- Finding the Right Menstrual Cup Size: Different menstrual cup brands offer a variety of sizes to accommodate varying cervical heights. By knowing your cervical position, you can select a cup with the appropriate length. For example, individuals with a high cervix may opt for a longer cup, while those with a low cervix may prefer a shorter one. Some users may switch between two different cups during their cycle, using a shorter one at the beginning of their cycle (when the cervix tends to sit lower as the uterus swells in size) and move to using a longer cup towards the middle and end of their cycle when the cervix retracts. Here's a list of our recommended menstrual cups for a high cervix and a list of the best menstrual cups for a low cervix. You can also check out our full menstrual cup comparison chart for detailed measurements of all the different menstrual cups.
- Avoiding Leaks and Discomfort: Using the knuckle test rule helps you determine how far up or down your cervix sits. A well-fitted menstrual cup should sit just below or around the cervix, creating a reliable seal and preventing leaks. If the cup is positioned too low or too high, it may cause discomfort or lead to leakage.
- Understanding Menstrual Cup Placement: Knowing your cervical position can guide you in understanding where to place the cup in your vaginal canal. For individuals with a high cervix, the cup can be positioned higher to achieve a secure fit. Conversely, those with a low cervix may need to position the cup lower, ensuring it remains entirely within the vaginal canal.
- Assisting in Cup Removal: When it's time to remove the menstrual cup, understanding your cervical position can simplify the process. If your cervix is low, the cup might be closer to the vaginal opening, making removal easier. On the other hand, a higher cervix may require a bit more effort, but with practice, it becomes more manageable.
- Accommodating Changes in Cervical Position: Throughout the menstrual cycle, the cervix can change its position due to hormonal fluctuations and fertility. By knowing your typical cervical height during different phases of your cycle, you can adjust your cup placement accordingly.
Measuring your cervical position using the knuckle test rule is a simple and effective way to enhance your menstrual cup experience. Understanding the height of your cervix allows you to select the right cup size, ensure a comfortable fit, prevent leaks and facilitate cup removal.
Remember, every individual's body is unique, and finding the perfect menstrual cup fit may take some trial and error. Don't be discouraged if it takes time to identify what works best for you.
Disclaimer: The information provided in this blog is for educational purposes only and should not be considered a substitute for professional medical advice. Always consult with a qualified healthcare provider for personalised guidance on your health.