Indicators of Secretory Activation in Mothers of Preterm Very Low Birth Weight Infants

Evaluating milk flow patterns using the high flow rate period during breast pumping

PROBLEM

Breast pumping practices have scope for improvement.

BACKGROUND

Breast milk weight measurement can be used to evaluate milk flow pattern dynamics during breast pumping.

AIM

To determine inter-individual differences in milk flow patterns and their practical implications based on high milk flow rate period (HFP) data among Japanese women expressing breast milk using an electric pump.

METHODS

This cross-sectional, observational study analysed data from 19 women (33.0 ± 3.9 years) nursing 1-6-month-old infants and with previous breast milk expression experience. Breast milk was weighed continuously during a 15-min single-breast electric pumping session. The HFP features and flow rate time (≥0.1 g/s) were analysed to determine each individual's milk flow pattern.

FINDINGS

The total expressed breast milk was 69.8 ± 42.5 g with a maximum individual flow rate of 0.5 ± 0.2 g/s. The breast milk yielded during the HFPs was 43.1 (34.4-81.3) g, accounting for 82.5 % (69.9-89.5 %) of the total expressed breast milk. HFP occurred 0-3 times during the 15-min session. Multiple discrete and continuous milk flow patterns were observed. Among those with discrete HFP, the HFP interval was 221 (68-371) s. Breast milk fat content changes and subjective residual milk measurements implied sufficient milk removal. A strong positive correlation was noted between HFP length and total breast milk expression volume.

DISCUSSION

Individual differences in milk flow patterns were observed among the women using HFP. Milk flow patterns were consistent with previous reports.

CONCLUSION

Milk flow pattern data can be used to guide individualised lactation support.

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.

Having Enough Milk to Sustain a Lactation Journey: A Call to Action

The rates of human milk feeding are suboptimal worldwide. Recommendations for healthy, term mother-infant dyads include early breastfeeding initiation, frequent skin-to-skin contact, and frequent breastfeeding. The normal physiology of lactation can be affected by prenatal factors such as diabetes, obesity, and excessive gestational weight gain. Furthermore, birth-related factors such as early-term gestation, stressful labor, unscheduled cesarean birth, and postpartum hemorrhage can additionally disrupt recommended practices such as early initiation of breastfeeding and skin-to-skin contact. Given that the first 2 to 3 days postpartum are critical to achieving timely secretory activation and establishing an adequate volume of milk, a proactive approach to care can include building awareness of risk factors and development of protocols for the effective early initiation of lactation.

Biomarker-based text messages to promote lactation success in mothers of critically Ill infants: a randomized controlled pilot study

OBJECTIVE

Infrequent breast pumping limits mother's own milk production in mothers of infants admitted to the neonatal intensive care unit. We aimed to determine the feasibility and benefit of biomarker-based personalized text messages on pumping frequency and milk sodium levels. A secondary aim examined lactation outcomes.

STUDY DESIGN

In this randomized controlled pilot study, 51 mothers were randomized to receive personalized text messages regarding pumping frequency or standard care.

RESULTS

There were no differences in pumped milk volume or sodium level, however, there was a trend towards the intervention group pumping more frequently, which was significant on day 5 (p = 0.035), and they lactated nearly 9 days longer. Post-hoc analysis found the intervention group tended to be more likely to pump ≥ 500 mL by day14 (p = 0.08), a marker of long-term lactation success.

CONCLUSION

Personalized biomarker-based text messages are feasible and may support lactation in mothers of critically ill infants.

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.

Novel At-Home Mother's Milk Conductivity Sensing Technology as an Identification System of Delay in Milk Secretory Activation Progress and Early Breastfeeding Problems: Feasibility Assessment

BACKGROUND

Prolonged exclusive breastfeeding is a public health priority and a personal desire by mothers; however, rates are low with milk supply challenges as a predominant cause. Early breastfeeding management at home is key. Milk electrolytes, mainly sodium ions, are accepted as biomarkers of secretory activation processes throughout the first weeks after birth and predictors for prolonged breastfeeding success, although they are not incorporated into routine care practice.

OBJECTIVE

The aim of this study was to test the feasibility of a novel handheld smartphone-operated milk conductivity sensing system that was designed to compute a novel parameter, milk maturation percent (MM%), calculated from milk sample conductivity for tracking individual secretory activation progress in a real-world home setting.

METHODS

System performance was initially evaluated in data collected from laboratory-based milk analysis, followed by a retrospective analysis of observational real-world data gathered with the system, on the spot in an at-home setting, implemented by lactation support providers or directly by mothers (N=592). Data collected included milk sample sensing data, baby age, and self-reported breastfeeding status and breastfeeding-related conditions. The data were retroactively classified in a day after birth-dependent manner. Results were compared between groups classified according to breastfeeding exclusivity and breastfeeding problems associated with ineffective breastfeeding and low milk supply.

RESULTS

Laboratory analysis in a set of breast milk samples demonstrated a strong correlation between the system's results and sodium ion levels. In the real-world data set, a total of 1511 milk sensing records were obtained on the spot with over 592 real-world mothers. Data gathered with the system revealed a typical time-dependent increase in the milk maturation parameter (MM%), characterized by an initial steep increase, followed by a moderate increase, and reaching a plateau during the first weeks postpartum. Additionally, MM% levels captured by the system were found to be sensitive to breastfeeding status classifications of exclusive breastfeeding and breastfeeding problems, manifested by differences in group means in the several-day range after birth, predominantly during the first weeks postpartum. Differences could also be demonstrated for the per-case time after birth-dependent progress in individual mothers.

CONCLUSIONS

This feasibility study demonstrates that the use of smart milk conductivity sensing technology can provide a robust, objective measure of individual breastfeeding efficiency, facilitating remote data collection within a home setting. This system holds considerable potential to augment both self-monitoring and remote breastfeeding management capabilities, as well as to refine clinical classifications. To further validate the clinical relevance and potential of this home milk monitoring tool, future controlled clinical studies are necessary, which will provide insights into its impact on user and care provider satisfaction and its potential to meet breastfeeding success goals.

The Utilization of Sodium Concentration in Human Milk from Pump-Dependent Mothers of Preterm Infants as a Measure of Milk Production

Objective: This study investigated changes in sodium concentrations in human milk from mothers of premature infants using different breast pumps for 14 days postpartum, and the correlation between the sodium concentration in mother's own milk (MOM) and the volume pumped. Study Design: This randomized controlled study recruited 66 mothers of premature infants delivered in our hospital from February to December 2018, and we assigned them to three groups using an envelope method. In intervention group 1, a hospital-grade electric breast pump was used from postpartum day 1 to 14; in intervention group 2, a hospital-grade electric breast pump was used on postpartum days 1 to 5 and a normal personal electric breast pump on postpartum days 6 to 14; in the control group, a personal normal electric breast pump was used from postpartum day 1 to 14. Data recorded included the breast milk volume pumped and milk sodium concentration. Results: The average daily volume of MOM pumped differed statistically (p < 0.05) between the intervention and control groups at postpartum days 7 and 14. The average daily volume pumped did not differ between intervention groups 1 and 2 by postpartum day 14 (p > 0.05). However, the time taken for the sodium concentrations to normalize differed significantly (p < 0.01). At postpartum day 5, the sodium concentrations of 73% of intervention group 1 and 2 mothers were within normal limits, and they were maintained until day 14. In comparison, only 41% of the controls had normal MOM sodium levels on day 5, and they were still high on day 7 in 27.3% of controls. Conclusions: In the early stage of lactation initiation (within 5 days postpartum), using a hospital-grade electric breast pump promotes lactation in mothers who deliver prematurely and the sodium concentrations normalize more quickly. Sodium can be used as an objective biomarker of MOM to evaluate the possibility of delayed lactation in mothers of premature infants, and it could assist interventions in the early postpartum period. Trial Registration: Chinese Clinical Trial Registry, ChiCTR2200061384.

Associations of Secretory Activation Breast Milk Biomarkers with Breastfeeding Outcome Measures

OBJECTIVE

The objective of this study was to explore associations between day 10 postpartum (D10) secretory activation biomarkers and the breastfeeding outcome measures.

STUDY DESIGN

This prospective longitudinal descriptive study collected antepartum, D10, and day 60 postpartum (D60) questionnaire data and D10 milk samples. Protein, lactose, and citrate were analyzed with enzymatic spectrophotometric assays. Sodium and potassium were analyzed with inductively coupled plasma optical emission spectrophotometry. Group comparison data were analyzed using χ², Fisher exact, and independent sample t tests, as appropriate, using SPSS for Mac (version 28).

RESULTS

Participants (n = 92) provided a D10 breastmilk sample and completed D10 questionnaires, and 83 completed D60 questionnaires. Participants with D10 impaired secretory activation sodium (>23.0 mM) were more likely to report D10 perceived insufficient milk supply, χ² = 7.002, P < .05; and less D10 feeding/pumping frequency a day, P < .05; and partial breastfeeding at D60, P < .05. Additionally, participants with D10 impaired secretory activation sodium-to-potassium ratio (sodium: potassium) > 0.8 were more likely to partially breastfeed at D60, P < .05.

CONCLUSION

Elevated milk sodium and sodium: potassium are biomarkers related to variables indicative of low milk supply. Therefore, immediate milk testing can be useful in identifying lactation compromise and improving breastfeeding duration. Because breastfeeding affords maternal and infant health benefits, clinicians should identify ways to measure lactation compromise in conjunction with an examination and clinical history to provide early interventions to increase breastfeeding duration and exclusivity.

Hormonal regulation of mammary gland development and lactation

Lactation is critical to infant short-term and long-term health and protects mothers from breast cancer, ovarian cancer and type 2 diabetes mellitus. The mammary gland is a dynamic organ, regulated by the coordinated actions of reproductive and metabolic hormones. These hormones promote gland development from puberty onwards and induce the formation of a branched, epithelial, milk-secreting organ by the end of pregnancy. Progesterone withdrawal following placental delivery initiates lactation, which is maintained by increased pituitary secretion of prolactin and oxytocin, and stimulated by infant suckling. After weaning, local cytokine production and decreased prolactin secretion trigger large-scale mammary cell loss, leading to gland involution. Here, we review advances in the molecular endocrinology of mammary gland development and milk synthesis. We discuss the hormonal functions of the mammary gland, including parathyroid hormone-related peptide secretion that stimulates maternal calcium mobilization for milk synthesis. We also consider the hormonal composition of human milk and its associated effects on infant health and development. Finally, we highlight endocrine and metabolic diseases that cause lactation insufficiency, for example, monogenic disorders of prolactin and prolactin receptor mutations, maternal obesity and diabetes mellitus, interventions during labour and delivery, and exposure to endocrine-disrupting chemicals such as polyfluoroalkyl substances in consumer products and other oestrogenic compounds.

Comparing the effect of a lactation-specific relaxation and visualisation intervention versus standard care on lactation and mental health outcomes in mothers of very premature infants (the EXPRESS trial): study protocol for a multi-centre, unmasked, randomised, parallel-group trial

Background

Premature birth is the leading cause of neonatal death and can cause major morbidity. Maximising the amount of maternal breastmilk given to very premature infants is important to improve outcomes, but this can be challenging for parents. Parents of infants receiving neonatal care also have high rates of anxiety and distress. There is growing evidence for the impact of maternal relaxation interventions on lactation, as well as mental health. The trial will assess whether a brief self-directed relaxation and visualisation intervention, recommended for use several times a day during expression of milk, improves lactation and mental health outcomes for mothers of very premature infants.

Methods

Multi-centre, randomised, controlled, unmasked, parallel-group trial with planned 132 participants who have experienced premature birth between 23 weeks and 31 weeks and 6 days of gestation and plan to express milk for at least 14 days. The primary outcome is the highest 24-h expressed milk yield recorded on any of day 4, day 14 or day 21 after birth. Secondary outcomes include exclusive breastmilk feeding at 36 weeks post-menstrual age and at 4 months after the estimated date of delivery, Spielberger State Trait Anxiety Index at day 21 and Post-traumatic stress Check List (for DSM 5) at day 21.

Discussion

Breastmilk feeding for premature infants is an important research priority, but there are few randomised controlled trials assessing interventions to help parents reach lactation goals in this challenging context. This trial will assess whether a no cost, easily scalable relaxation tool has a role in this setting. Given the lack of harm and potential for immediate dissemination, even a small benefit could have an important global impact.

Trial registration

ISRCTN16356650. Date assigned: 19/04/2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06570-9.

A Comparison of the Timing of Hand Expressing of Human Milk With Breast Massage to Standard Care for Mothers of Preterm Infants: An Exploratory Pilot Using a Randomized Controlled Design

BACKGROUND

Globally, 10% of all births are preterm. Access to human milk via manual breast expression is required to reduce the incidence of adverse outcomes related to prematurity. However, there is little evidence to recommend optimum timing to commence breast expression in mothers of preterm infants or the most effective method.

RESEARCH AIMS

(1) To test feasibility of recruitment and compliance to the protocol and (2) to determine influence of using hand expressing and breast massage on milk production, engorgement, mastitis, and breastfeeding status at 3 months.

METHODS

This study was an exploratory parallel two-group, pilot randomized controlled trial. Mothers of preterm infants at a metropolitan maternity hospital in Queensland Australia (N = 31) were randomized to receive either hand expressing and breast massage within the 1st hr of birth or standard care, hand expressing within 6 hr of birth, to determine the influence on milk production, engorgement, mastitis, and breastfeeding status at 3 months.

RESULTS

Feasibility targets were not met; however, valuable learning from this trial uncovered barriers facing midwives in the birth suite to commencing expressing in the 1st hr of birth. There was no difference in occurrence of secondary outcomes, although trends support future study.

CONCLUSIONS

Overall, unpredictability of preterm birth influenced our ability to recruit participants. Important directions for future study design would benefit from incorporating expressing times up to 6 hr with a replicable breast massage.

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.