Using a breast pump effectively starts with ensuring the correct fit between the nipple and the pump’s flange, also known as a breast shield. Nipple sizing involves measuring the diameter of the nipple at its base, where the tissue meets the surrounding areola. An accurate measurement is the primary step toward maximizing milk expression and maintaining comfort throughout the pumping journey.
Why Accurate Sizing is Crucial
When a flange is too small, the friction created within the tunnel can cause pain and irritation to the delicate tissue. Restricted movement may also lead to swelling, impeding the natural flow of milk from the ducts. Chronic use of an undersized flange increases the risk of blocked milk ducts and can result in incomplete emptying of the breast.
Conversely, a flange that is too large allows too much of the surrounding areola tissue to be pulled deep into the pump tunnel. This action can stretch the sensitive tissue, causing discomfort and bruising. An overly large shield also reduces the efficiency of milk removal because the vacuum pressure is not optimally focused. The resulting friction can lead to tissue damage and a reduction in milk yield.
Preparing for Measurement
Before beginning the measurement process, gather the proper tools to ensure accuracy. A simple household ruler with clear millimeter markings or a flexible measuring tape will suffice. Many pump manufacturers also provide printable sizing guides, which are easily accessible online. Adequate lighting and privacy are helpful to minimize distractions and allow for precise observation.
The timing of the measurement is the most important preparation step, as nipple size is dynamic and changes during stimulation. Measurements should not be taken when the nipple is fully relaxed or cold, as this yields an inaccurate, smaller result. It is recommended to measure immediately after a few minutes of active pumping or manual stimulation has caused the nipple to become erect. This captures the size the nipple will be in its active state.
Step-by-Step Guide to Measurement
To begin the physical measurement, locate the base of the nipple, where the tissue begins to rise from the surrounding areola. The goal is to measure the diameter of the nipple itself across its widest point, ignoring the darker areola skin entirely. Using the ruler or sizing guide, place the zero mark at one edge of the nipple base.
Hold the measuring tool flat across the center of the nipple, ensuring it rests gently without compressing the tissue. Read the measurement at the opposite edge of the nipple base, recording the number in millimeters (mm). Millimeters are the standard unit used by pump manufacturers for flange sizing, making this precision necessary for accurate selection.
It is important to perform this measurement on both breasts, as size asymmetry is common among lactating individuals. Many people find that one side is several millimeters larger or smaller than the other, which may require using two different flange sizes. Taking the measurement multiple times, perhaps at different times of the day, can help confirm the most consistent and accurate size before purchasing equipment.
Applying Your Measurement to Flange Selection
The raw measurement obtained in millimeters does not directly translate to the flange size printed on the breast shield packaging. The flange size must always be slightly larger than the measured nipple diameter to accommodate the natural expansion of the tissue during an active pumping session. This difference allows the nipple to move freely within the tunnel and prevents painful rubbing against the plastic walls.
The general consensus is to add between 2 and 4 millimeters (mm) to the measured nipple diameter to determine the appropriate flange size. For instance, if the measured nipple diameter is 17 mm, the recommended starting flange size would be 21 mm. A larger measurement of 20 mm would suggest beginning with a 24 mm flange, though personal comfort should dictate the final selection.
Once a flange is selected, the ultimate confirmation of fit is a visual check during an active pumping session. The nipple should be centered perfectly within the tunnel and move back and forth rhythmically without excessive friction or pain. Minimal areola should be drawn into the tunnel, and the entire nipple should be moving freely toward the end of the tunnel.
If the nipple rubs painfully against the sides or if significant areola is pulled deep into the shield, the size requires immediate adjustment to prevent tissue damage. It is also important to remember that nipple size can change throughout the postpartum period, especially in the first few weeks or months as milk supply regulates. Re-measuring and making adjustments over time is a normal part of maintaining an effective and comfortable pumping routine.