A breast pump flange, also known as a breast shield, is the funnel-shaped part of the pump that fits directly over the nipple and areola to create a vacuum seal. This seal extracts milk effectively by mimicking the suction and motion of a baby feeding. Choosing the correct flange size is fundamental, as it directly influences both the comfort of the pumping experience and the overall efficiency of milk expression. An ill-fitting flange can lead to significant discomfort, reduced milk output, and potential injury to the breast tissue, making proper sizing essential for maintaining a sufficient milk supply.
Why Flange Size Matters for Pumping Efficiency and Comfort
Using an incorrect flange size impacts milk removal and physical well-being. When a flange is too small, the nipple may rub painfully against the sides of the tunnel, causing friction, bruising, and tissue damage. This friction can lead to swelling and restricted milk flow, potentially signaling the body to decrease supply over time.
Conversely, a flange that is too large allows excessive areola tissue to be pulled into the tunnel along with the nipple. This action can compress the milk ducts beneath the areola, hindering complete milk drainage. Incomplete emptying is a primary cause of complications such as clogged milk ducts and mastitis, which may require medical intervention. A well-fitting flange focuses suction correctly on the nipple, allowing for thorough and comfortable milk expression.
Step-by-Step Guide to Measuring Your Nipple Diameter
The first step in determining the correct flange size is to measure the diameter of your nipple accurately when it is in a relaxed state. Tools for this measurement include a standard metric ruler, a flexible measuring tape, or a specialized printable nipple sizing tool. The measurement should be taken across the base of the nipple, which is the widest part where the nipple meets the areola.
It is crucial to measure only the nipple itself, excluding the surrounding areola tissue. This measurement is best taken before a pumping session or feeding, as the nipple tissue can swell and temporarily increase in size after stimulation. Since nipple sizes often differ, measure both sides separately to ensure an optimal fit for each breast.
Once the diameter measurement is taken in millimeters (mm), add a small allowance to determine the appropriate flange size. Generally, adding 2 to 4 mm to the measured diameter provides the necessary space for the nipple to move freely and expand slightly during pumping. For instance, a 17 mm nipple would typically require a flange size between 19 mm and 21 mm. This buffer accounts for the elongation and slight swelling of the nipple under vacuum.
Visual and Comfort Cues for Proper Flange Fit
While pre-pumping measurement provides a starting point, the fit must ultimately be verified by observing the nipple’s behavior during an active pumping session. With a correct fit, the nipple should be centered in the flange tunnel and move smoothly back and forth without rubbing against the side walls. Only the nipple should be drawn into the tunnel, with minimal to no areola tissue being pulled in.
Signs of an improper fit include the nipple dragging or sticking painfully against the sides of the tunnel, which suggests the flange is too small. If the flange is too large, a significant portion of the areola will be sucked into the tunnel, leading to discomfort and potentially reducing milk expression efficiency. Another indicator of an ill-fitting flange is the appearance of the nipple after pumping; it should look elongated but healthy, not reddened, bruised, or blanched (turning white or blue).
A pumping session should feel comfortable, or at least not painful, and the breast should feel noticeably softer and well-drained afterward. If discomfort, pinching, or a burning sensation occurs, it signals that the current flange size is incorrect and an adjustment is needed. If the visual cues indicate a size mismatch, trying the next size up or down and re-evaluating the comfort and milk output is the recommended course of action.
Addressing Special Circumstances and Fit Variations
The pumping journey often involves circumstances that require adjustments beyond the initial size calculation. For those with very small nipples, pump manufacturers may not offer flanges smaller than 21 mm, necessitating the use of flange inserts. These inserts are placed inside a larger flange to reduce the tunnel diameter, allowing users (e.g., 15 mm or 17 mm) to achieve a proper fit.
Another variation is the presence of elastic nipples, which stretch excessively down the flange tunnel when vacuum is applied. If the nipple stretches to hit the back of the tunnel, it can cause pain and inefficiency. Experts recommend using a flange size closer to the exact base measurement or trying specialized soft silicone flanges designed to manage this stretching.
Flange size is not static and may change over the course of the pumping period. Postpartum swelling may subside, causing nipple size to decrease, or an increase in milk supply could lead to a temporary increase in size. It is common to require different flange sizes for each breast, so measuring both sides independently throughout the journey is necessary.