Understanding Your Cervix: Functions, Changes, and Choosing the Right Menstrual Cup with Leia

The cervix is a remarkable and often underestimated organ — the gateway between your vagina and uterus. Understanding how it works is essential for choosing the right menstrual cup and monitoring your reproductive health.

In this guide, we'll cover what the cervix does, how its position changes throughout your cycle, and why cervix height matters when selecting a menstrual cup.

What Is the Cervix?

The cervix is a cylindrical structure at the lower end of the uterus, featuring a central opening called the os. It connects the vaginal canal to the uterine cavity.

Interestingly, the surface of the cervix is largely devoid of pain receptors — which is why procedures like Pap smears feel like pressure rather than sharp pain.

Key Functions of the Cervix

Protective Barrier

The cervix forms a robust barrier between the vagina and the uterus, preventing bacteria and pathogens from ascending. Cervical mucus plays a significant role in trapping microorganisms and maintaining a sterile uterine environment.

Sperm Transport

During the fertile window, the cervix opens slightly and becomes more receptive, allowing sperm to navigate through toward the fallopian tubes for potential fertilization.

Mucus Secretion Throughout Your Cycle

Cervical mucus changes predictably throughout the menstrual cycle:

Tracking these changes can help you understand your fertility patterns.

After menstruation — thick, opaque, sticky (forming a "mucus plug" that blocks the entrance)
Near ovulation — clear, thin, slippery, resembling raw egg white (guiding and protecting sperm)
After ovulation — thick and impenetrable again

Role in Pregnancy and Childbirth

During pregnancy, the cervix remains firm, long, and closed, protecting the developing fetus. During labor, it thins (effacement) and opens (dilation) up to 10 cm to allow delivery.

Cervix Position: High, Medium, or Low

Your cervix position varies throughout your cycle — and this matters for menstrual cup selection:

During menstruation — sits lower, os softens and opens slightly for menstrual flow
During ovulation — moves higher, becomes softer, os opens slightly
After ovulation — higher, firmer, tightly closed

How to Check Your Cervix Height

Checking your cervix height is simple and takes just a minute:

Wash your hands thoroughly
Get comfortable — lie down with knees bent or squat
Insert two clean fingers into your vagina
Feel for a firm, rounded structure with a small indentation (the os)

Interpreting Your Results

Your cervix might also sit slightly off-center — this is entirely normal.

When to see a doctor: If you experience pain, unusual discharge, or bloody spotting during self-examination (outside of your period), schedule a medical appointment.

Barely reach it → high cervix
Touch it easily → medium cervix
Find it right away → low cervix

Why Cervix Height Matters for Menstrual Cup Selection

Understanding your cervical height is one of the most important factors when choosing a menstrual cup:

Low cervix — needs a shorter, more compact cup. Standard cups may be too long, causing discomfort or protruding
Medium cervix — most standard cups will work comfortably
High cervix — a longer cup or one with a longer stem may be easier to remove

Finding Your Perfect Fit

An anatomically designed cup that accounts for cervix variations will provide the best fit — preventing leaks, ensuring comfort, and being virtually imperceptible during wear.

If you're unsure which size is right for you, try a cup finder quiz that considers your cervix height, flow intensity, and whether you've given birth.

Key Takeaways

Learn how to choose the right cup based on your cervix height, or take our cup finder quiz for a personalized recommendation.

The cervix serves as a protective barrier, sperm guide, and mucus producer
Its position changes throughout your cycle — lower during menstruation, higher during ovulation
Cervix height directly affects which menstrual cup size will fit comfortably
Checking your cervix height takes just a minute and helps you avoid common cup-fitting mistakes