A breast pump flange, also known as a breast shield, is the funnel-shaped piece that forms a seal around the breast to facilitate milk expression. Its primary function is to draw the nipple into the tunnel and direct the extracted milk into a collection container. Selecting the proper flange size is important for comfort and efficiency. An incorrectly sized flange can cause pain, nipple trauma, and tissue damage, which may lead to reduced milk output and issues like clogged ducts. Finding the correct fit ensures maximum milk removal and a comfortable pumping experience.
Measuring to Determine Initial Flange Size
The initial step in finding the right flange is to measure the nipple diameter before a pumping session. Do not measure after pumping or nursing, as the nipple will be temporarily swollen. For the most accurate measurement, gently stimulate the nipple first to make it protrude.
Use a ruler or measuring tape marked in millimeters (mm) to find the diameter across the base of the nipple, where it meets the areola. The measurement should include only the nipple itself, excluding the surrounding areola. Because nipple size can vary, measure both sides independently.
Once the measurement is taken, add 2 to 4 millimeters to the measured diameter to determine the initial flange size. This added space accounts for the slight expansion of the nipple during pumping and ensures it does not rub against the tunnel walls. For example, an 18 mm nipple suggests an initial flange size between 20 mm and 22 mm. This provides a starting point, but the actual fit must be confirmed through visual inspection and comfort cues while pumping.
Visual and Comfort Cues During Pumping
Observing the nipple’s movement inside the flange tunnel while pumping is the most reliable way to confirm a proper fit. When the flange fits correctly, the nipple should be centered and move freely back and forth with the suction cycle. The nipple should not rub or chafe against the sides of the tunnel, as this indicates the flange is too small.
A small margin of the areola may be drawn into the tunnel, but excessive tissue should not be pulled past the neck of the flange. The breast motion should be gentle and rhythmic, not aggressive tugging. Pumping should feel like a strong, steady pulling sensation, but it should never cause sharp pain, pinching, or burning.
After the pumping session, the appearance of the nipple offers further confirmation of the fit. The nipple may appear slightly elongated but should retain its natural color and not show signs of swelling or injury. If the nipple is discolored, compressed, or misshapen, the fit needs adjustment.
Troubleshooting Common Signs of Incorrect Fit
Incorrect flange sizing often presents with clear, uncomfortable symptoms that signal a need for adjustment. Recognizing these signs helps prevent injury and maintain efficient milk expression. Symptoms of a flange that is too small are distinct from one that is too large, requiring different corrective actions.
Flange Too Small
A flange that is too small causes the nipple to rub severely against the sides of the tunnel, leading to friction and pain. Low milk output may occur because the tight fit compresses the milk ducts. A tell-tale sign is nipple blanching, where the nipple appears white or compressed after pumping due to restricted blood flow. If these symptoms are present, the flange size should be increased.
Flange Too Large
Conversely, if the flange is too large, a significant portion of the areola will be pulled deep into the tunnel with the nipple. This excessive pulling can cause swelling, soreness, and chafing on the areola. The areola tissue may also appear bunched or compressed, and the pump may not achieve an effective seal, resulting in inefficient milk removal. In this case, the flange size should be decreased, or a silicone insert can be used to reduce the tunnel diameter.