Flange Size Matters: A Comparative Pilot Study of the Flange FITS^TM Guide Versus Traditional Sizing Methods

Pumping is a common practice in the United States, but it can be uncomfortable and lead to concerns about milk supply. The fit of the flange, or breast shield, used while pumping can contribute to or alleviate these problems. Flanges are available in a wide variety of sizes, and there are inconsistencies in guidance provided by healthcare providers and pump manufacturers for parents choosing a size. There have been no studies comparing different methods of sizing in terms of comfort and milk output.

The aim of this research was to examine differences in milk output and comfort using two methods of flange sizing.

A within-subject cross-over design with a convenience sample of parents exclusively feeding their own human milk was used to compare comfort and milk yield between using smaller-fit and standard-fit flanges. Participants pumped for 1 week with each set of flanges and recorded milk output and comfort outcome measures. Data were collected on participant demographics, nipple measurements, and flange sizes used.

When compared to the newer small-size fitting, participants using the standard fit flanges had significantly less milk output (mean difference = -15.0 g, 95% CI [-25.0, -5.0], d = -0.51, p = 0.004) and less comfort (mean difference = -1.2, 95% CI [-1.6, -0.91], d = -1.23, p < 0.001).

Flange fitting is a process that should be individualized to the patient and may require a trial of one or more sizes during a pumping session. Smaller sizes determined using this individualized process and starting with nipple tip measurement may be used without compromising milk output or comfort.