The menstrual cup is a flexible, reusable device inserted into the vagina to collect menstrual fluid, while an Intrauterine Device (IUD) is a small, T-shaped contraceptive placed inside the uterus. These two devices can generally be used together, as the IUD sits inside the uterus and the cup resides in the vaginal canal. However, specific precautions are mandatory to prevent complications like IUD expulsion, requiring diligent attention to proper technique.
Understanding the Primary Risk
The primary concern when combining a menstrual cup with an IUD is the risk of IUD expulsion or displacement. Expulsion occurs when the device moves out of its correct position within the uterus, potentially partially or entirely falling out. Displacement means the IUD has shifted, which can significantly reduce its effectiveness as a contraceptive and may cause discomfort.
While the overall risk of IUD expulsion is low, typically ranging from 2–10% in the first year regardless of menstrual product, some studies suggest the rate is higher among menstrual cup users. Research indicates that this elevated risk is most often connected to the physical act of removing the cup. If the cup is removed incorrectly, the mechanical action can inadvertently pull on the IUD strings, leading to the device shifting position.
The potential for IUD movement is greatest immediately following insertion, with the first few months being the most susceptible period. For individuals with an IUD, this risk means a loss of contraceptive protection and possible symptoms such as severe cramping. The risk of expulsion may also vary depending on the specific type of IUD used, with some copper IUDs showing a higher association with cup use in long-term studies.
How the Vacuum Effect Increases Risk
The mechanism that makes a menstrual cup effective is the same one that poses a risk to the IUD: the creation of a seal, or vacuum, in the vaginal canal. Once correctly inserted, the cup expands to conform to the vaginal walls, forming an airtight seal that holds it in place and prevents leaks. This seal is necessary for the cup to function as intended.
If this seal is not fully broken before removal, the downward force applied when pulling the cup can create negative pressure. This suction effect extends up the vaginal canal toward the cervix. The IUD strings hang slightly out of the cervix and into the upper part of the vagina, placing them in the vicinity of the cup’s rim.
When the vacuum is intact, the strong downward pull may tug on the IUD strings or pull at the cervix itself. This mechanical action can dislodge the IUD from its secure placement inside the uterus. Therefore, the physical pressure from an intact seal, rather than simple friction, is the central mechanism that can lead to IUD displacement.
Essential Removal Techniques
The most important step for safe menstrual cup use with an IUD is consistently and completely breaking the vacuum seal before extraction. Before attempting to remove the cup, it is helpful to relax the pelvic floor muscles, which can be achieved by squatting or sitting comfortably over a toilet. This position also shortens the vaginal canal, making the cup more accessible.
To break the seal, a clean finger must be inserted high enough to reach the cup’s base, not just the stem or removal tab. The user should then gently pinch or press the side of the cup to let air rush in, which equalizes the pressure and releases the suction. A distinct “pop” or rush of air can often be felt or heard, indicating the seal has been successfully broken.
Once the seal is completely released, the cup can be gently folded or tilted to ease its passage out of the body. It is important to guide the cup down and out while being mindful of the IUD strings, avoiding any sudden or forceful tugging motions on the cup’s stem. By ensuring the suction is eliminated, the risk of the cup inadvertently pulling on the cervix or IUD strings is significantly minimized.
Monitoring and Consulting a Healthcare Provider
Regular self-monitoring is a necessary practice for anyone using an IUD, and it becomes even more important when using a menstrual cup. The IUD has thin strings that hang a short distance from the cervix. Checking these strings monthly, typically after the menstrual period, confirms the IUD remains in the correct position. To check, a clean finger is inserted into the vagina to feel for the two fine strings.
If the IUD strings feel significantly shorter, longer, or if they cannot be felt at all, the device may have moved, and a healthcare provider should be contacted immediately. It is also possible for the IUD itself to be felt—a hard, plastic part protruding from the cervix—which is a definite sign of displacement or partial expulsion. Backup contraception should be used in these situations.
Other warning signs that require prompt medical consultation include new or severe cramping, persistent abdominal pain, unusual vaginal discharge, or pain during sexual intercourse. Though some of these symptoms can be normal side effects of IUD use, a sudden change or increase in their severity may indicate that the device has shifted. Never attempt to push the IUD back into place or pull on the strings to adjust the device.