Early postpartum pumping behaviors, pumped milk volume, and achievement of secretory activation in breast pump-dependent mothers of preterm infants.

OBJECTIVE: Pumping studies in mothers of preterm infants are limited by self-reported pumping behaviors and non-objective measures of pumped milk volume and secretory activation (SA). METHODS: Non-randomized observational study of first 14 days postpartum in 29 mothers of preterm infants. Smart pumps measured and stored pumping behaviors and pumped milk volume. Selective ion electrodes measured sodium and sodium:potassium ratio to determine SA. Generalized estimating equations, cluster analyses and multivariate regression were used. RESULTS: SA was delayed (median 5.8 days) and impermanent. Each additional daily pumping increased odds of SA within 2 days by 48% (p = 0.01). High-intensity pumping mothers (N = 17) had greater daily and cumulative pumped milk volume than low-intensity pumping mothers (N = 12). Pumping variables showed daily changes in the first week, then plateaued. CONCLUSION: The first week postpartum is critical for optimizing pumping behaviors. Accurate, objective measures of pumping behaviors, pumped milk volume and SA are a research priority.

Milk Biomarkers of Secretory Activation in Breast Pump-Dependent Mothers of Preterm Infants: An Integrative Review.

Background: Lack of mother's own milk (MOM) at discharge from the neonatal intensive care unit (NICU) is a global problem and is often attributable to inadequate MOM volume. Evidence suggests that the origins of this problem are during the first 14 days postpartum, a time period that includes secretory activation (SA; lactogenesis II, milk coming in). Objectives: To describe and summarize evidence regarding use of MOM biomarkers (MBMs) as a measure of SA in pump-dependent mothers of preterm infants in the NICU and to identify knowledge gaps requiring further investigation. Methods: An integrative review was conducted using Whittemore and Knafl methodology incorporating the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist. A search using electronic databases MEDLINE (through PubMed) and CINAHL (Cumulative Index to Nursing and Allied Health Literature) and reference lists of included articles was conducted. Results: Of the 40 articles retrieved, 6 met the criteria for inclusion. Results revealed the following five findings: (1) Achievement of SA defined by MBMs is delayed and/or impaired in mothers of preterm infants. (2) MBMs are associated with pumped MOM volume. (3) Achievement of SA defined by MBMs is associated with pumping frequency. (4) Delayed and/or impaired achievement of SA defined by MBMs may be exacerbated by maternal comorbidities. (5) There is a lack of consensus as to which MBM(s) and analysis techniques should be used in research and practice. Conclusions: MBMs hold tremendous potential to document and monitor achievement of SA in mothers of preterm infants, with multiple implications for research and clinical practice.

Prepregnancy Body Mass Index Is Associated with Time-Dependent Changes in Secretory Activation Measures During the First 7 Days Postpartum in Breast Pump-dependent Mothers of Premature Infants.

Background: Little is known about the biology of secretory activation (SA) in overweight and obese (OW/OB) mothers who are breast pump dependent with a premature infant in the neonatal intensive care unit. Objective: To compare time-dependent changes in daily pumped milk volume, maternal milk sodium (Na) concentration, and Na-to-potassium (K) ratios (Na:K) in the first 14 days postpartum in breast pump-dependent mothers with prepregnancy body mass index (BMI) <27 and BMI ≥27 kg/m2. Design/Methods: This secondary analysis for 39 subjects, 44% (n = 17) with prepregnancy BMI <27 and 56% (n = 22) with BMI ≥27, included transformed data of outcome measures, chi-square, t-tests, and growth curve models. Results: For days 1-7, daily pumped milk volume increased significantly more rapidly for mothers with BMI <27 (65.82 mL/d) versus BMI ≥27 (33.08 mL/d), but the daily rate of change in pumped milk volume during days 8-14 was not statistically different. Daily milk Na concentration decreased significantly faster in BMI <27 (-3.93 mM/d) versus BMI ≥27 (-2.00 mM/day) during days 1-7, but was not significantly different for days 8-14. No statistical differences were noted for Na:K ratio for either time period. Conclusion: These data add biologic evidence to previous research, suggesting delayed or impaired SA in OW/OB mothers, and suggest that the window of opportunity for research and clinical interventions is days 1-7 postpartum in this population.

Mother's Own Milk Biomarkers Predict Coming to Volume in Pump-Dependent Mothers of Preterm Infants.

OBJECTIVE: To assess serial secretory activation biomarker concentrations (sodium [Na], potassium [K], Na:K, protein, lactose, and citrate) in mother's own milk (MOM) from breast pump-dependent mothers of preterm infants to determine associations with coming to volume (CTV), defined as producing at least 500 mL/day MOM by day 14 postpartum. STUDY DESIGN: We collected serial MOM samples and pumped MOM volume data for 14 days postpartum in mothers who delivered at <33 weeks of gestation. Regression models and the Mann-Whitney U test were used to evaluate associations. RESULTS: Among 40 mothers, 39 (mean gestational age, 28.8 weeks; 67% overweight/obese; 59% nonwhite) had paired MOM volume and biomarker data; 33% achieved CTV between postpartum days 6 and 14. In univariate models, MOM Na on postpartum day 5 and Na:K on days 3 and 5 were associated with CTV. Mothers achieving CTV were more likely to have postpartum Na:K ≤1 on day 3 (75% vs 25%; P = .06) and ≤0.8 on day 5 (69% vs 10%; P < .01). In a multivariable regression model, day 5 Na:K (1 unit decrease in Na:K: OR, 18.7; 95% CI, 1.13-311.41; P = .049) and maternal prepregnancy body mass index (BMI) (1 unit increase in BMI: OR, 0.88; 95% CI, 0.78-0.99; P = .04) were associated with CTV between postpartum days 6 and 14. CONCLUSIONS: Secretory activation and CTV were compromised in breast pump-dependent mothers with preterm delivery. CTV was predicted by MOM Na level and Na:K. These biomarkers have potential as objective point-of-care measures to detect potentially modifiable lactation problems in a high-risk population.

Measures of Secretory Activation for Research and Practice: An Integrative Review.

Background: Maternal concern about inadequate milk volume commonly emerges in the first 2 weeks postpartum, a critical lactation period that includes secretory activation. This review summarizes the biology of secretory activation and evaluates the accuracy and feasibility of published measures of secretory activation. Materials and Methods: A systematic search of measures of secretory activation for mothers of healthy term and preterm infants yielded 62 abstracts. Following additional screening, 15 publications qualified for quantitative synthesis review and were evaluated with respect to accuracy (validated with another measure of secretory activation in the same mother) and feasibility (accessibility, cost, and ease of use). Results:Maternal perception of milk coming in (MP) is the most feasible measure, but its accuracy has not been established. Patterns of increase in maternal milk volume have been validated with maternal milk-borne biomarkers in breastfeeding, and breast pump-dependent mothers and normal values have been published. Accuracy of serial maternal urinary lactose concentrations has not been established for secretory activation and lacks feasibility. Maternal milk biomarkers are the accurate standard to which other measures are compared but currently lack feasibility for routine use. Conclusions: Use of secretory activation measures can personalize lactation care by matching maternal risk with appropriate diagnostics. Priorities for research and practice include validation of MP as a population-based screening tool, implementation of techniques that measure patterns of increase in milk volume for moderate risk populations, and the development of milk biomarker science for point-of-care use in the most complicated lactation scenarios.

Human Milk Biomarkers of Secretory Activation in Breast Pump-Dependent Mothers of Premature Infants.

OBJECTIVE: Mothers of premature infants confront barriers to coming to volume (CTV; ≥500 mL/day mother's own milk [MOM] by postpartum day 14), a strong predictor of continued MOM provision at neonatal intensive care unit (NICU) discharge. We sought to determine concentrations of secretory activation biomarkers (MOM sodium, total protein, lactose, and citrate) during the first 14 postpartum days and to describe relationships among these biomarkers, pumped MOM volume, CTV, and pumping frequency. STUDY DESIGN: This descriptive observational study collected serial MOM samples, pumped MOM volume, and pumping frequency during the first 14 postpartum days in 16 breast pump-dependent mothers who delivered <33 weeks gestation. Daily biomarker concentrations were compared to published normal values for mothers of term infants. Relationships among biomarkers, pumped MOM volume, and pumping frequency were determined. RESULTS: On postpartum day 5, only 40% of MOM samples revealed normal concentrations of all four biomarkers, and normalcy was not maintained throughout the first 14 days. All eight mothers (50%) who achieved CTV had normal concentrations for four biomarkers at 5.4 ± 3.5 days postpartum and had more cumulative pumping sessions by day 5 (p = 0.03). A dose-response relationship between number of normal biomarkers and pumped MOM volume was demonstrated for postpartum days 3 (p = 0.01) and 5 (p = 0.04). CONCLUSION: Secretory activation is delayed in mothers who deliver prematurely and is closely tied to CTV, MOM volume, and pumping frequency. MOM biomarkers hold promise as objective research outcome measures and for point-of-care testing to identify and proactively manage mothers at risk for compromised lactation.