Menstrual cups are a popular, sustainable choice for period management. The most frustrating initial hurdle for many users is getting the flexible device to fully expand and form a secure seal inside the vaginal canal. This expansion, often described as the cup “popping open,” is necessary for the cup to function correctly by creating a vacuum effect against the vaginal walls. When the cup fails to achieve this perfectly rounded shape, it remains partially collapsed, preventing the necessary seal from forming and leading to leakage and discomfort.
The Core Causes of Non-Opening
The failure of a menstrual cup to open is caused by physical forces acting against the cup’s natural tendency to return to its bell shape. The technique used to fold the cup for insertion plays a significant role. Complex folds, such as the punch-down or the 7-fold, compress the silicone more tightly, requiring a greater rebound force to fully unfurl once inside. Simpler folds, like the C-fold, are often more reliable because they involve less material compression, allowing the rim to spring open with less resistance.
The cup’s material and firmness also directly impact its ability to open. Softer cups are generally more comfortable but possess less outward force and struggle to overcome the natural pressure of the vaginal walls. Firmer cups rebound more aggressively and are more likely to pop open without manual assistance. Inadequate moisture or lubrication increases friction between the rim and the vaginal tissue, physically preventing the cup from sliding open. Additionally, if the user is tense or rushing insertion, the pelvic floor muscles can involuntarily contract, narrowing the vaginal canal and physically squeezing the cup, which prevents full expansion.
Immediate Fixes for a Stuck Fold
If the cup has not fully opened after insertion, several corrective actions can be attempted before removal. The most effective first step is a gentle twist and turn of the cup to encourage the rim to unfurl. Grip the base of the cup, not the stem, and rotate it 360 degrees; this motion helps the rim catch the vaginal wall and break the remaining tension holding the fold.
If rotation is insufficient, you can try the base press technique to temporarily introduce air and release the remaining compression. Gently push the base of the cup inward slightly with a finger to momentarily break any partial suction that has formed, and then quickly release it. This small influx of air can provide the final encouragement for the rim to snap open.
Another reliable method is the finger sweep. Slide a clean finger along the vaginal wall up to the rim of the cup, pushing the tissue away to create space. This allows you to physically check for any dents or remaining folds along the rim and manually nudge the collapsed section until it is round.
Changing your body position, such as squatting down or bearing down slightly with your pelvic muscles, can also help. This action shortens the vaginal canal and shifts the cervix, creating a better environment for the cup to settle and fully open.
Ensuring Proper Placement and Seal
Long-term success in getting the cup to open starts with preparation and correct insertion mechanics. Applying water or a water-based lubricant to the cup’s rim before insertion dramatically reduces friction against the vaginal walls, allowing the cup to glide in and open more smoothly. Oil-based lubricants must be avoided, as they can degrade the silicone material of the cup over time.
The angle and depth of insertion are also critical. The vaginal canal is angled toward the tailbone, so the cup should be inserted horizontally, aiming toward the lower back. The cup should sit relatively low in the canal, below the cervix. Inserting the cup too high or at the wrong angle can cause the rim to press directly against the cervix, physically preventing a seal from forming and causing discomfort.
After insertion, the post-insertion check is necessary to confirm success. Run a finger around the entire circumference of the cup’s rim to ensure it feels perfectly round and smooth, with no flat spots or dents. A slight tug on the stem should produce resistance, which confirms the formation of the required vacuum seal. Finally, be aware of the small air release holes located just below the rim, as these must remain clear to allow air to enter the cup for it to open and to allow air to escape when removing the cup to break the seal.