A breast pump flange, also known as a breast shield, is the funnel-shaped cup that fits over the nipple and areola during a pumping session. Its primary function is to create a secure vacuum seal against the breast tissue, which allows the pump to draw the nipple into the central tunnel. This action facilitates milk extraction by mimicking the stimulation and mechanics of a baby nursing. The wrong flange size definitively affects milk output, as an improper fit compromises the entire physiological process of milk removal.
The Physiology of Milk Removal and Flange Fit
The success of milk expression depends on the pump’s ability to create a consistent, gentle vacuum that effectively stimulates the breast. This vacuum draws the nipple into the flange tunnel, where the milk ducts are compressed and emptied. Proper flange sizing is necessary to ensure that the nipple can move freely while the areola remains relatively stationary.
If the flange is too small, it can compress the milk ducts at the base of the nipple, which physically impedes the flow of milk out of the breast. This compression also causes friction and rubbing against the sides of the tunnel. Restricted movement and friction can lead to swelling and trauma, further reducing the efficiency of milk extraction and causing a painful experience.
Conversely, a flange that is too large pulls too much areola tissue deep into the tunnel with the nipple. This excessive pulling disrupts the vacuum seal, leading to reduced suction and less effective duct stimulation. When the areola is pulled in excessively, it often results in swelling of the breast tissue, which can block the ducts and prevent complete breast emptying. Improper fit signals that milk is not being fully removed, which can lead to a long-term decrease in overall milk production.
Recognizing Symptoms of an Improper Flange Size
Identifying the symptoms of an incorrect flange fit is the first step toward restoring comfortable and efficient milk expression. The most immediate and noticeable sign of a poor fit is physical discomfort or pain during or after pumping. Pumping should not be a painful experience, and persistent soreness, chafing, or pinching sensations indicate the size needs adjustment.
A visual cue for a flange that is too small is when the nipple rubs noticeably against the sides of the tunnel as the pump cycles. A more concerning sign is nipple blanching, where the nipple appears white or significantly lighter in color after pumping due to restricted blood flow. This trauma can severely inhibit the release of milk and cause lasting pain.
When a flange is too large, a significant portion of the areola might be pulled deep into the tunnel, sometimes past the first third of the flange. Output symptoms are also telling; consistently low milk volume or a sudden drop in output suggests inefficient milk removal. Incomplete breast drainage due to poor fit can also lead to frequent occurrences of clogged milk ducts or engorgement.
Practical Guide to Nipple Measurement
Determining the correct flange size requires accurately measuring the diameter of the nipple itself, not the surrounding areola. Use a flexible measuring tape or a ruler marked in millimeters to measure the nipple across its base. It is helpful to stimulate the nipple gently before measuring to ensure a more accurate reading of its size.
Once the diameter of the nipple base is measured in millimeters, add two to four millimeters to that number to determine the ideal flange size. This added space allows the nipple to be drawn into the tunnel without rubbing against the sides while leaving the areola mostly outside the tunnel. For example, a nipple measuring 18 mm typically requires a 21 mm or 22 mm flange.
Visually check the fit once you begin pumping with the new size. The nipple should be centered and move back and forth freely within the tunnel without pulling in too much areola or causing pain. Since nipples can be different sizes, it is possible to need a different flange size for each breast to ensure optimal comfort and efficiency.
Other Common Causes of Low Milk Output
While flange size is a frequent cause of pumping difficulties, other factors can also contribute to a reduction in milk output.
Equipment Issues
The equipment itself can be the culprit, particularly if small, working parts like membranes, duckbills, or valves are worn out or damaged. These pieces are responsible for maintaining the pump’s vacuum pressure, and wear and tear can drastically reduce suction, leading to inefficient milk removal.
Maternal and Pumping Factors
Maternal factors, such as high stress levels, can interfere with the let-down reflex by increasing the release of cortisol, which inhibits milk-ejection hormones. Maintaining proper hydration and nutrition is important, as milk production is a demanding biological process. Hormonal shifts, such as those that occur during the menstrual cycle or a new pregnancy, can also temporarily decrease milk supply.
Pumping frequency and duration are major determinants of milk volume. Infrequent or short pumping sessions signal to the body that less milk is needed, potentially leading to a gradual decrease in supply. Ensuring that the breasts are fully emptied is the primary way to signal the body to continue producing milk.