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



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).


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.


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.


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.

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Fig. 1
Fig. 2: Time-dependent changes in pumping behaviors for cohort (N = 29).
Fig. 3: Time-dependent changes in pumped milk volume and milk Na concentration for cohort (N = 29).
Fig. 4: Time-dependent changes in pumping behaviors for HIPG (N = 17) and LIPG (N = 12).
Fig. 5: Time-dependent differences in pumped milk volume and milk Na concentration for HIPG (N = 17) and LIPG (N = 12).

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Data availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.


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Authors and Affiliations



Conceptualization/design: RH, CMP, PPM. Supervision: PPM, Data Curation: MS, JJ, CMP, CSF. Writing of original draft: RH, CMP, PPM. Writing, reviewing, and editing: RH, CMP, JJ, MS, CSF, PPM. All authors have read and agreed to the published version of the article.

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Correspondence to Clarisa Medina-Poeliniz.

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Potential conflict of interest: PPM serves as a consultant to Medela for educational activities. RH holds a position on Medela’s scientific advisory board.

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Rush University Medical Center IRB review. All methods were performed in accordance with the relevant guidelines and regulations.

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Hoban, R., Medina-Poeliniz, C., Signorile, M. et al. Early postpartum pumping behaviors, pumped milk volume, and achievement of secretory activation in breast pump-dependent mothers of preterm infants. J Perinatol (2024).

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