A common and frustrating experience is feeling a pad fail, resulting in a leak. Understanding the factors contributing to pad failure—which range from product selection to placement and wear time—can significantly reduce the chance of leakage. Most leaks result from a mismatch in product capability, user application, or the physical limits of the pad’s function over time.
Mismatch Between Flow and Pad Absorbency
The most frequent reason for a pad leak is using a product that cannot handle the volume of fluid being released. Menstrual flow is a mixture of blood, tissue, and secretions, with a typical total volume ranging from 10 to 80 milliliters over the course of a period. Flow is rarely consistent, and the heaviest days often occur at the start of the cycle.
Pads are labeled with terms like “light,” “regular,” and “heavy” to indicate capacity, but this is a rough guide, not a precise measure of fluid volume. For example, a regular pad may hold 15 to 20 milliliters, while an overnight pad may handle 30 to 40 milliliters before reaching saturation. Choosing a pad that is too short or too thin for a heavy flow day means the fluid will quickly exceed the pad’s capacity.
The length of the pad is also important, especially for overnight use or heavier flow that tends to spread. Overnight pads are designed with greater length and wider coverage in the back to catch flow that shifts when lying down. Selecting the wrong size means the fluid may bypass the absorbent core entirely, running off the edges before the pad reaches its maximum holding capacity. This failure requires switching to a higher absorbency or a longer product to match the volume and spread of the flow.
Issues with Positioning and Movement
Even a correctly chosen pad can leak if it is not properly aligned to catch the flow. The pad must be centered both front-to-back and side-to-side on the underwear so the absorbent material is positioned directly where the fluid is released. If the pad is placed too far forward or backward, flow can miss the absorbent area and run onto the fabric instead.
Movement and activity contribute to shifting and subsequent leakage, often creating gaps at the sides. Pad wings wrap around the underside of the underwear to anchor the pad and prevent side-to-side shifting. If the wings are not secured firmly or the underwear is too loose, the pad can bunch up or slide, exposing the edges of the absorbent core and creating channels for fluid runoff.
The type and fit of the underwear also play a significant role in securing the pad. Slippery, synthetic fabrics, like silk or polyester blends, often prevent the pad’s adhesive strip from forming a secure bond. Brief-style underwear that holds the pad snugly against the body is more effective at preventing shifting than a looser-fitting style. When a pad shifts, the fluid is no longer directed into the absorbent center, leading to a leak.
Structural Failure, Bunching, and Over-Saturation
A pad that leaks after several hours of wear is often experiencing structural or functional failure. The most straightforward reason is over-saturation, meaning the pad has reached its maximum holding capacity. Once the absorbent core is full, the fluid cannot be absorbed and instead pools on the surface, quickly running off the sides or ends.
A more subtle failure occurs when the pad “bunches” or twists, which ruins its ability to contain fluid. Bunching is often caused by continuous movement and friction against the body, especially if the adhesive bond has weakened. When the pad wrinkles, the protective side barriers collapse, and the surface material forms creases that direct fluid away from the center and out to the side edges.
The adhesive strip itself can fail when exposed to moisture, body heat, and friction over an extended period. If the adhesive loosens, the pad peels away from the fabric, allowing it to move freely and bunch up. Wearing a pad for too long compromises the integrity of the material and the adhesive, making a leak more likely, even if the pad does not appear completely full. Frequent changing, even if the flow seems light, is necessary to prevent this functional degradation and maintain the pad’s intended shape.