Asynchronous milk ejection in human lactating breast: case series

Re-thinking benign inflammation of the lactating breast: A mechanobiological model

Despite the known benefits of breastfeeding for both infant and mother, clinical support for problems such as inflammation of the lactating breast remains a research frontier. Breast pain associated with inflammation is a common reason for premature weaning. Multiple diagnoses are used for inflammatory conditions of the lactating breast, such as engorgement, blocked ducts, phlegmon, mammary candidiasis, subacute mastitis, mastitis and white spots, which lack agreed or evidence-based aetiology, definitions and treatment. This is the first in a series of three articles which review the research literature concerning benign lactation-related breast inflammation. This article investigates aetiological models. A complex systems perspective is applied to analyse heterogeneous and interdisciplinary evidence elucidating the functional anatomy and physiology of the lactating breast; the mammary immune system, including the human milk microbiome and cellular composition; the effects of mechanical forces during lactation; and the interactions between these. This analysis gives rise to a mechanobiological model of breast inflammation, in which very high intra-alveolar and intra-ductal pressures are hypothesized to strain or rupture the tight junctions between lactocytes and ductal epithelial cells, triggering inflammatory cascades and capillary dilation. Resultant elevation of stromal tension exerts pressure on lactiferous ducts, worsening intraluminal backpressure. Rising leucocyte and epithelial cell counts in the milk and alterations in the milk microbiome are signs that the mammary immune system is recruiting mechanisms to downregulate inflammatory feedback loops. From a complex systems perspective, the key mechanism for the prevention or treatment of breast inflammation is avoidance of excessively high intra-alveolar and intra-ductal pressures, which prevents a critical mass of mechanical strain and rupture of the tight junctions between lactocytes and ductal epithelial cells.

25 Years of Research in Human Lactation: From Discovery to Translation

Researchers have recently called for human lactation research to be conceptualized as a biological framework where maternal and infant factors impacting human milk, in terms of composition, volume and energy content are studied along with relationships to infant growth, development and health. This approach allows for the development of evidence-based interventions that are more likely to support breastfeeding and lactation in pursuit of global breastfeeding goals. Here we summarize the seminal findings of our research programme using a biological systems approach traversing breast anatomy, milk secretion, physiology of milk removal with respect to breastfeeding and expression, milk composition and infant intake, and infant gastric emptying, culminating in the exploration of relationships with infant growth, development of body composition, and health. This approach has allowed the translation of the findings with respect to education, and clinical practice. It also sets a foundation for improved study design for future investigations in human lactation.

Untargeted lipidomics using liquid chromatography-ion mobility-mass spectrometry reveals novel triacylglycerides in human milk

Human milk provides the infant with the essential nutritive and non-nutritive factors required for health, growth and development. The human milk lipidome is complex, but comprises predominantly triacylglycerides. Historically, the fatty acid profile of the entire human milk lipidome has been investigated, and many relationships have been identified between infant health and fatty acids. Most of these fatty acids are, however, delivered to the infant as triacylglycerides. Using liquid chromatography-ion mobility-mass spectrometry, the objective of this study was to characterise the triacylglyceride profile of human milk and elucidate relationships between the triacylglyceride profile and infant outcomes in a cohort of 10 exclusively breastfeeding woman-infant dyads. 205 triacylglycerides were identified, including 98 previously not reported in human milk. The dose of specific triacylglycerides differed in relation to infant health, such as lauric acid containing TAGs, which were delivered in significantly higher dose to healthy infants compared to unwell infants.

Cutaneous perfusion of the human lactating breast: a pilot study with laser Doppler perfusion monitoring

OBJECTIVE

Knowledge on the hemodynamics of the human lactating breast contributes to our understanding of lactation physiology, as well as the development and management of breastfeeding problems. The objective of this pilot study was to investigate whether laser Doppler perfusion monitoring (LDPM) can be employed to measure physiological changes in mammary cutaneous perfusion during milk extraction.

APPROACH

We evaluated mammary cutaneous perfusion with LDPM in nine lactating women during milk extraction in both the ipsilateral ('milk extracting') and contralateral ('passive') breast. Fourier domain filtering of the LDPM signal was applied to correct for the influence of the periodic tissue movement caused by the breast pump.

MAIN RESULTS

Cutaneous perfusion increased temporary during 23.7  ±  18.9 s by 18%-74% for all women who sensed their milk ejection reflex (n  =  6) in both the ipsilateral and contralateral breast. For those women who did not sense a milk ejection reflex (n  =  3), the changes in cutaneous perfusion were less outspoken (maximally 26%).

SIGNIFICANCE

This pilot study provides new insights into mammary hemodynamics and demonstrates that LDPM is a promising method for the further investigation of physiological changes in mammary cutaneous perfusion during milk ejection. Objective feedback on the occurrence and progression of milk ejection can support lactation research in general, maternal breastfeeding confidence, and may be an early indicator for the development of breastfeeding problems.

Facilitators and barriers of breastfeeding late preterm infants according to mothers' experiences

BACKGROUND

Late preterm infants account for the majority of preterm births. They are at an increased risk of neonatal mortality and morbidity and are less likely to initiate breastfeeding and to be exclusively breastfed at discharge compared to infants born at term. The aim of this study was to identify the facilitators and barriers to breastfeeding during hospital stays according to the experiences of mothers of late preterm infants.

METHODS

We conducted a cross-sectional questionnaire survey. Mothers who intended to breastfeed and had given birth to a newborn admitted to level I and II care, with a gestational age of 34 0/7 to 36 6/7 weeks, were enrolled. Sociodemographic data, neonatal variables, mode of feeding and feeding status at discharge were also collected.

RESULTS

A total of 92 mothers who had given birth to 121 infants were enrolled. At discharge, any human milk was fed to 94 % of infants, with exclusively human milk being fed in 43 % of cases; exclusively formula was fed to 6 % of infants. In the multivariate analysis, having expressed breast milk was independently associated with an increased risk of being fed with either any human milk or formula only (OR = 2.73, 95 % CI 1.05-7.1, p = 0.039), whereas being encouraged to practice kangaroo mother care tended to have a protective effect (OR = 0.46, 95 % CI 0.2-1.06, p = 0.07).

CONCLUSIONS

Based on the present findings, health care professionals should strive to fully implement breastfeeding support for mothers of late preterm infants who intend to breastfeed, in particular optimizing breast milk expression and promoting kangaroo mother care. Further studies are needed to gain further insight into the complex interplay of the factors that modulate breastfeeding outcome in late preterm infants.