The breast pump flange is the cone-shaped plastic or silicone piece that connects your body to the pump mechanism. Its function is to create an airtight seal around the nipple and areola, allowing the pump to generate the necessary vacuum suction for milk removal. A properly sized and placed flange ensures the nipple is drawn gently into the tunnel, mimicking an infant’s latch to stimulate milk flow. The right fit directly impacts your comfort, the efficiency of milk expression, and the prevention of potential tissue damage.
Determining Your Correct Flange Size
Selecting the appropriate flange size begins with accurately measuring the diameter of your nipple. Measure across the base of the nipple, where it meets the areola, excluding the areola itself. Use a metric ruler or flexible measuring tape to find the width in millimeters (mm).
It is helpful to measure after a few minutes of pumping or manual stimulation, as nipple size can temporarily increase during letdown. Since size can vary between breasts, measure each side independently. After determining the nipple diameter, add a small margin to account for the natural expansion of the nipple tissue during pumping.
Most experts recommend adding between 2 to 4 mm to your measured nipple diameter to determine your initial flange size. For instance, if your nipple measures 17 mm across the base, a flange size of 19 mm to 21 mm would be a good starting point. This added space allows the nipple to move freely back and forth within the flange tunnel without rubbing against the sides.
Nipple size can change over the course of your pumping journey, especially as your milk supply regulates, often around ten weeks postpartum. What felt comfortable initially may not be the optimal size later on, necessitating a periodic reassessment of your fit. Using a size that is too small or too large can restrict milk flow, cause discomfort, and lead to reduced milk output.
Proper Technique for Flange Placement
Before beginning your pumping session, ensure your hands and all pump parts that contact the breast are clean. Apply a small amount of lubrication, such as a nipple cream or balm, to the edge of the flange tunnel to reduce friction. This helps the nipple glide smoothly and minimizes the chance of irritation once suction begins.
Achieving perfect centering of the nipple within the flange tunnel is crucial for proper placement. Hold the flange up to your breast and visually confirm the nipple is aligned dead-center before turning on the pump. If the nipple is off-center, friction against the tunnel walls will cause pain and affect proper drainage.
Once centered, gently press the flange firmly against your breast to establish a secure, airtight seal. Gaps between the skin and the edge of the flange will break the vacuum, leading to insufficient suction. You can achieve a better seal by leaning slightly forward and using the “areola pull-back” technique, slightly compressing the breast tissue to ensure the flange rests evenly on the skin.
After securing the flange, start the pump on the lowest suction setting and gradually increase the vacuum. Find the maximum comfortable suction level, which should never cause pain, as discomfort can inhibit the milk ejection reflex. Your nipple should be pulled straight into the tunnel, moving rhythmically with the pump’s cycle, without the surrounding areola being dragged deep inside.
Signs of an Improper Fit
Visual and physical cues indicate if your flange size or placement is incorrect. If the flange is too small, the sides of your nipple will rub painfully against the walls of the tunnel as it moves back and forth. After pumping, a too-small flange often leaves the nipple looking compressed, chafed, or discolored, sometimes appearing white or blanched.
Conversely, a flange that is too large allows excessive amounts of the areola to be pulled into the tunnel along with the nipple. This causes noticeable tugging and potentially a pressure ring around the areola after the session. Both scenarios of poor fit can lead to low milk yield, as the pump cannot effectively remove milk when the tissue is compressed or improperly stimulated.
Pain, pinching, or sharp discomfort during the pumping session is the clearest sign that a correction is needed. If you experience this, immediately stop the pump, re-center the flange, or consider trying a different size. Persistent pain or tissue damage, such as bruising or cracking, suggests the size is wrong and should prompt you to remeasure or consult with a lactation professional.