Feasibility of Using Point-of-Care Biomarkers of Secretory Activation to Address Early, Unplanned Weaning Among Healthy, Term Dyads in Community Settings: A Pilot Study

<b><i>Background:</i></b> Delayed and/or impaired secretory activation (SA) achievement is a risk factor for early unplanned lactation cessation. This pilot study (1) evaluated the feasibility of in-home daily milk collection; (2) compared daily maternal self-report of breast fullness with mother's own milk (MOM) biomarkers of SA; and (3) examined SA patterns in association with lactation outcomes through 3 months postpartum. <b><i>Methods:</i></b> Twelve mother-infant dyads were enrolled at term (median gestational age (GA) = 39.9 weeks, range = 38.3-41.1 weeks). After birth, participants self-reported breast fullness and collected milk samples daily for a week. Infant weight gain and milk intake by test-weights were assessed postpartum during a week 1 routine infant outpatient visit and again during a week 2 home visit. Milk samples were tested for sodium (Na) and potassium (K) using portable ion selective electrodes. Timing of SA achievement was denoted as the first day breast fullness was self-rated ≥ 3, Na concentration was < 12 mmol/L, or the Na/K ratio was < 0.6. Breastfeeding duration and exclusivity were measured at 1, 2, and 3 months postpartum. <b><i>Results:</i></b> By day 6, all mothers self-reported SA achievement, while only 72-82% achieved SA using MOM biomarkers. Cohen's kappa between the timing of SA by maternal self-report and MOM biomarkers showed lack of agreement (κ = 0.05 and 0.08), but was high between MOM Na and Na/K ratio (κ = 0.87). Three patterns of SA by MOM biomarkers emerged (<i>mature and stable, impermanent, and delayed)</i> with implications for infant weight loss/gain at 1 week postpartum. These patterns were not associated with breastfeeding exclusivity through 3 months postpartum in this highly motivated sample. <b><i>Conclusion:</i></b> MOM biomarkers of SA achievement are feasible and have significant potential for use in community settings.