Relationships between the Intakes of Human Milk Components and Body Composition of Breastfed Infants: A Systematic Review.

Human milk provides all of the elements necessary for infant growth and development. Previous studies have reported associations between breastfeeding and a reduced risk of developing obesity and late-onset metabolic disorders; however, the underlying mechanisms are poorly understood. Recently, intakes of human milk components have been associated with infant body composition, which is likely partially implicated in the reduced risk of developing childhood obesity among breastfed infants. In this systematic review, we searched electronic bibliographic databases for studies that explored relationships between the 24 h intakes of human milk macronutrients and bioactive components and infant body composition and/or growth parameters. Of 13 eligible studies, 10 assessed relationships of infant body composition and growth outcomes with human milk macronutrients, while 8 studies assessed relationships with human milk bioactive components. Significant time-dependent relationships with infant anthropometrics and body composition were found for intakes and no relationships for concentrations of several human milk components, such as lactose, total protein, and human milk oligosaccharides, suggesting that measuring concentrations of human milk components without quantifying the intake by the infant may provide a limited understanding. Future studies investigating the effect of human milk components on infant growth and body composition outcomes should consider measuring the actual intake of components and employ standardised methods for measuring milk intake.

Longitudinal changes in wellbeing amongst breastfeeding women in Australia and New Zealand during the COVID-19 pandemic.

The COVID-19 pandemic has impacted new mothers' wellbeing and breastfeeding experience. Women have experienced changes in birth and postnatal care and restricted access to their support network. It is unclear how these impacts may have changed over time with shifting rates of infection and policies restricting movement and access to services in Australia and New Zealand. This study investigated the longitudinal effect of the COVID-19 pandemic on breastfeeding and maternal wellbeing in Australia and New Zealand. Mothers (n = 246) completed an online survey every 4 weeks for 6 months that examined feeding methods, maternal mental wellbeing, worries, challenges, and positive experiences during the pandemic. Mothers maintained high full breastfeeding rates at 4 months (81%) which decreased to 37% at 6 months. Perceived low milk supply contributed to the earlier cessation of full breastfeeding. Poor infant sleep was associated with stress, perinatal anxiety, mental wellbeing, and breastfeeding status. Although mothers initially reported that lockdowns helped with family bonding and less pressure, prolonged lockdowns appeared to have adverse effects on access to social networks and extended family support.    Conclusion: The results highlight the changing dynamic of the pandemic and the need for adaptable perinatal services which allow mothers access to in-person services and their support network even in lockdowns. Similarly, access to continuous education and clinical care remains critical for women experiencing concerns about their milk supply, infant sleep, and their own wellbeing. What is Known: • The COVID-19 pandemic and lockdown restrictions have significantly affected perinatal mental health, disrupted maternal services, and subsequent breastfeeding. What is New: • In Australia and New Zealand, breastfeeding women experienced challenges to their mental wellbeing, sleep, and breastfeeding, which was likely exacerbated over time by the pandemic. Lockdowns, while initially beneficial for some families, became detrimental to maternal support and wellbeing.

Breastfeeding in a COVID-19 world.

PURPOSE OF REVIEW: The coronavirus disease 2019 (COVID-19) pandemic has changed the birthing and postnatal experience of women. This review highlights how policy changes have affected pregnant and breastfeeding women, the evidence for continued breastfeeding and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, and how the pandemic's unexpected consequences have affected these women's wellbeing. Additionally, we postulate the future of lactation and perinatal support as the pandemic continues. RECENT FINDINGS: Women who have given birth during the pandemic have had restricted access to postnatal care. Although pregnant and breastfeeding women who contract SARS-CoV-2 are more vulnerable to poor health outcomes than their nonpregnant counterparts, they are also at higher risk of mental health difficulties, with limited access to support. Continued breastfeeding may be protective to the infant, offering passive immunity against SARS-CoV-2, and vaccination against COVID-19 is safe and effective for pregnant and lactating women. Innovative and adaptable lactation care, including holistic perinatal, mental health, and social support services, both digital and in-person, will help mothers continue breastfeeding during future outbreaks. SUMMARY: Continued breastfeeding and vaccination may confer protection to the infant against SARS-CoV-2 infection. New mothers should not be isolated in future pandemics. Prioritizing lactation and perinatal care, including in-person services, remains paramount to optimizing breastfeeding during COVID-19.

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.

Wellbeing of Breastfeeding Women in Australia and New Zealand during the COVID-19 Pandemic: A Cross-Sectional Study.

During the COVID-19 pandemic, breastfeeding women have experienced restricted access to support, placing them at increased risk of mental health concerns and limited breastfeeding assistance. This study investigated the effect of the pandemic on feeding choices and maternal wellbeing amongst breastfeeding mothers living in Australian and New Zealand. We conducted a cross-sectional online survey that examined feeding methods, maternal mental wellbeing, worries, challenges, and positive experiences during the pandemic. Most women were exclusively breastfeeding (82%). Partial breastfeeding was associated with perceived low milk supply and longer pregnancy duration during the pandemic. Reduced mental health and wellbeing was associated with lower levels of family functioning, increased perceived stress, and perinatal anxiety. Longer pregnancy duration during the pandemic was associated with lower mental health wellbeing scores, while higher perceived stress scores were reported for regions with higher COVID-19 infection rates and women with perceived low milk supply. Women reported that the pandemic resulted in less pressure and more time for family bonding, while worries about the pandemic, family health, and parenting challenges were also cited. Mental health concerns of breastfeeding women appear to be exacerbated by COVID-19, highlighting a critical need for access to mental health and broader family support during the pandemic.

Breast shield design impacts milk removal dynamics during pumping: A randomized controlled non-inferiority trial.

INTRODUCTION: While many studies have investigated the importance of optimizing pumping patterns for milk removal, the influence of breast shield design on milk removal has not been the focus of extensive investigation. This study aimed to determine the effectiveness of breast shields with either a 105° or a 90° flange opening angle on breast drainage and milk volume expressed during pumping. MATERIAL AND METHODS: This study was a cross-over, randomized controlled non-inferiority trial (Registration; NCT03091985). Mothers (n = 49) of breastfeeding infants participated in the study over two study sessions. Participants were randomly assigned to pump both breasts simultaneously for 15 minutes with either the 105° or 90° breast shield in the first session, and the other shield in the second session. Effectiveness (breast drainage) and efficiency (volume expressed) of both breast shields were assessed after 15 minutes of pumping. Intention-to-treat and per protocol analyses were performed to determine if the 105° breast shield was non-inferior to the 90° breast shield for breast drainage and volume expressed. Perceived comfort was assessed via questionnaire. RESULTS: The 105° breast shield was both non-inferior and superior compared to the standard 90° shield for breast drainage (intention-to-treat, 3.87% (0.01-7.72), P = .049) and volume expressed (intention-to-treat, 9.14 mL (1.37-16.91), P=.02). In addition, the 105° shield was rated as feeling more comfortable (P < .001) and as having an improved fit to the breast (P < .001) compared to the 90° shield. CONCLUSIONS: Expressing with the 105° breast shield was more efficient, effective and comfortable compared to the 90° shield. Breast shield design can significantly impact pumping outcomes, and an opening angle of 105° improves both the dynamics and comfort of milk removal.

Vacuum characteristics of the sucking cycle and relationships with milk removal from the breast in term infants.

BACKGROUND: The importance of an infant's intra-oral vacuum in milk removal from the breast has been established. However, the relationship between the vacuum curve and milk transfer is not well understood. AIMS: To investigate the parameters of the infant suck cycle in relation to the volume of milk removed from the breast. STUDY DESIGN: Cross-sectional study to elucidate the role of infant intra-oral vacuum in efficient milk removal from the breast. SUBJECTS: Nineteen fully breastfed term infants. METHODS: Intra-oral vacuum was recorded during monitored breastfeeds using a pressure transducer. Ultrasound imaging (milk flow) and respiratory inductive plethysmography (swallowing) were used to determine the nutritive sucking (NS) portion of the feed. Milk intake was determined by weighing infants before and after feeds. Vacuum traces of the first and next 2min of NS from the first breast were analysed. RESULTS: The volumes of milk removed during both NS periods were negatively associated with peak vacuum (p<0.001) and rate of vacuum application (p<0.001), and positively related to area under first half of the suck cycle (p<0.001). Most parameters changed significantly from the first 2min of NS to the next 2min including significant reduction in peak vacuum and area under first half of the suck cycle. CONCLUSION: These results further support the role of intra-oral vacuum, specifically optimal peak vacuum, in effective and efficient milk removal during breastfeeding. It also appears that infants modify their sucking dynamics to adapt to changes in milk flow during milk ejection as the breast empties.

Ultrasound Imaging of Breastfeeding--A Window to the Inside: Methodology, Normal Appearances, and Application.

Ultrasound imaging has been employed as a noninvasive technique to explore the sucking dynamics of the breastfeeding infant over the past 40 years. Recent improvements in the resolution of ultrasound images have allowed a more detailed description of the tongue movements during sucking, identification of oral structures, and measurements of nipple position and tongue motion. Several different scanning planes can be used and each show sucking from a different perspective. Ultrasound techniques and image anatomy are described in detail in this review and provide the basis for implementation in the objective assessment of breastfeeding.

Suck-Swallow-Breathe Dynamics in Breastfed Infants.

Despite the importance of the suck-swallow-breathe reflex during breastfeeding, a large proportion of our understanding is derived from bottle-feeding studies. Given the differences in the delivery of milk during breast and bottle feeding, it is imperative that a more general view of the suck-swallow-breathe and milk removal process during breastfeeding is available. This systematic review aimed to assess the evidence for the mechanism of milk removal during breastfeeding; evaluate how the term infant coordinates sucking, swallowing, breathing (SSwB) and cardiorespiratory patterns; and how these patterns change with maturation during breastfeeding. A literature search of PubMed and MEDLINE was performed to assess the mechanism of milk removal and patterns of sucking, swallowing, breathing, and cardiorespiratory control during breastfeeding in healthy term infants. Seventeen studies were selected and a narrative synthesis was performed. Nine studies assessing the infant sucking mechanism consistently provided evidence that vacuum is essential to milk removal from the breast. The limited data on swallowing and breathing and cardiorespiratory control showed mixed results. Overall, results highlighted the high variability in breastfeeding studies and suggested that swallowing, breathing, and cardiorespiratory patterns change with maturation, and within a breastfeed. These findings show potential for devising breastfeeding interventions for populations at risk of SSwB problems. However, consistent methods and definitions of breastfeeding parameters are required before interventions can be adequately developed and tested.

Evidence of improved milk intake after frenotomy: a case report.

Ankyloglossia (tongue tie) is a well-recognized cause of breastfeeding difficulties and, if untreated, can cause maternal nipple pain and trauma, ineffective feeding, and poor infant weight gain. In some cases, this condition will result in a downregulation of the maternal milk supply. Milk-production measurements (24-hour) for a breastfeeding infant with ankyloglossia revealed the ineffective feeding of the infant (78 mL/24 hours), and a low milk supply (350 mL/24 hours) was diagnosed. Appropriate management increased milk supply (1254 mL/24 hours) but not infant milk intake (190 mL/24 hours). Test weighing convincingly revealed the efficacy of frenotomy, increasing breastfeeding milk transfer from 190 to 810 mL/24 hours. Postfrenotomy, breastfeeding almost completely replaced bottle-feeding of expressed breast milk. This case study confirms that ankyloglossia may reduce maternal milk supply and that frenotomy can improve milk removal by the infant. Milk-production measurements (24-hour) provided the evidence to confirm these findings.

Longitudinal changes in suck-swallow-breathe, oxygen saturation, and heart rate patterns in term breastfeeding infants.

BACKGROUND: Despite the differences in breastfeeding and bottle-feeding, our understanding of how suck-swallow-breathe (SSwB), oxygenation, and heart rate patterns change as the infant ages is based predominantly on bottle-feeding studies. Therefore, this study aimed to measure how SSwB, oxygenation, and heart rate patterns changed during the first 4 months of lactation in term breastfeeding infants. METHODS: Infants less than 1 month postpartum (n = 15) were monitored early in lactation and again later in lactation (2-4 months postpartum). Simultaneous recordings of vacuum, tongue movement, respiration, swallowing, oxygen saturation, and heart rate were made during both nutritive sucking and non-nutritive sucking during breastfeeding. RESULTS: Infants transferred a similar amount of milk (P = .15) over a shorter duration later in lactation (P = .04). Compared to early lactation, suck bursts became longer (P < .001), pauses became shorter (P < .001), vacuum levels decreased (all P < .05), oxygen saturation increased (P < .001), and heart rate decreased (P < .001) later in lactation. CONCLUSION: This study confirmed that term infants become more efficient at breastfeeding as they age, primarily by extending their suck bursts and pausing less. Although infants demonstrated satisfactory SSwB coordination during early lactation, they showed a level of adaption or conditioning at later lactation by applying weaker vacuum levels and demonstrating improved cardiorespiratory responses.

Ultrasound imaging of infant sucking dynamics during the establishment of lactation.

BACKGROUND: Infant sucking problems are frequently implicated in early weaning during breastfeeding, yet our understanding of early sucking dynamics is limited. OBJECTIVE: This study aimed to describe infant sucking patterns during breastfeeding at secretory activation and determine whether they changed by the time of established lactation. METHODS: Sucking patterns and milk intake of 15 breastfeeding infants were assessed on day 3.2 ± 0.8 and later at follow-up, 16.0 (11.3-22.8) days postpartum. Nipple diameters, tongue movement, nipple position, and suck rate during nutritive sucking (NS) and non-nutritive sucking (NNS) were measured from ultrasound scans of the intra-oral cavity during breastfeeding. Milk intake and LATCH scores were also recorded. RESULTS: As the tongue lowered during a suck cycle, the nipple increased in size (P < .001), milk flowed into the intra-oral space and the nipple moved closer to the hard-soft palate junction (P < .001). During NS, nipple diameters and the mid-tongue movement were greater than during NNS (P < .001). As the infant aged, the mid-tongue lowered further (P = .002), suck rates became faster (P < .001) and milk intake increased (P = .004), however, no differences were seen for LATCH scores (P = .34). CONCLUSION: Differences in tongue movement between NS and NNS suggest that there is an altered sucking action when milk flow is absent. Similar sucking patterns at day 3 and during established lactation imply that infants have a mature sucking pattern in the early postpartum period.

A comparison of early sucking dynamics during breastfeeding after cesarean section and vaginal birth.

BACKGROUND: The impact of cesarean section (CS) birth and pethidine for post-CS epidural analgesia on early breastfeeding behavior is unclear. This study aimed to measure infant sucking and breastfeeding behavior in infants of mothers who delivered by CS (CS group) and used pethidine patient-controlled epidural analgesia (PCEA) after CS with that of infants who were delivered by vaginal birth (V group), during secretory activation and again after the establishment of lactation. SUBJECTS AND METHODS: Sucking dynamics and milk intake of breastfeeding infants were assessed on approximately 3 and 20 (follow-up) days postpartum (CS group, n=19; V group, n=15). Nipple diameters, tongue movement, and nipple position during sucking were measured from ultrasound scans of the intra-oral cavity during breastfeeding. Time of the first breastfeed and day of breast fullness were recorded, and infant neurobehavior was assessed. RESULTS: CS infants displayed more anterior tongue movement on Day 3 than at follow-up compared with the V group, which showed a similar amount of movement at each assessment (p for interaction<0.001). Compared with the V group, the CS group showed faster suck rates, especially on Day 3 (p<0.001), later times to first breastfeed (p=0.01) and breast fullness (p=0.03), and lower neurobehavioral scores (p=0.047). Breastfeeding duration and milk intake were similar between groups. CONCLUSIONS: Although the observed effect of CS birth followed by pethidine PCEA after CS during the period of secretory activation was small, our results indicate that successful initiation of lactation may require additional breastfeeding support and monitoring at Day 3 postpartum for mothers who undergo CS.

Oxygen Saturation and Suck-Swallow-Breathe Coordination of Term Infants during Breastfeeding and Feeding from a Teat Releasing Milk Only with Vacuum.

Background. Vacuum is an important factor in milk removal from the breast, yet compression is the predominant component of milk removal from bottle teats. Since bottle-feeding infants have lower oxygen saturation, vacuum levels, and different suck-swallow-breathe (SSwB) coordination to breastfeeding infants, we hypothesised that when infants fed from a teat that required a vacuum threshold of -29 mmHg for milk removal, that oxygen saturation, heart rate, and suck-swallow-breathe (SSwB) patterns would be similar to those of breastfeeding. Study Design. Infants (n = 16) were monitored during one breastfeed and one feed from the experimental teat. Simultaneous recordings were made of oxygen saturation, heart rate, vacuum, tongue movement, respiration, and swallowing. Results. There were no differences in oxygen saturation and heart rate between the breast and the teat. Infants displayed fewer sucks and breaths per swallow during nutritive sucking (NS) compared to non-nutritive sucking (NNS). The number of sucks per breath was similar for NS and NNS although respiratory rates were slower during NS. These patterns did not differ between the breast and the teat. Conclusion. These results suggest that vacuum may be conducive to safe and coordinated milk removal by the infant during both breast and bottle-feeding.

Tongue movement and intra-oral vacuum of term infants during breastfeeding and feeding from an experimental teat that released milk under vacuum only.

BACKGROUND: Recent literature supports the theory that vacuum is integral to the removal of milk from the breast rather than peristaltic compression of the breast. AIM: We aimed to determine if breastfed infants could remove breast milk from an experimental teat designed to release milk only when a vacuum is applied. METHODS: Submental ultrasound images and intra-oral vacuum measurements were recorded simultaneously during both a breastfeed and a feed with the experimental teat. RESULTS: Infants placed the nipple and teat a similar distance from the nipple hard-soft palate junction when the tongue was lowered (4.7 mm vs 5.3 mm). As the tongue lowered the nipple and teat expanded evenly although the nipple expanded more than the teat (3.1mm vs 1.5 mm). Both baseline (-31 mm Hg vs -12 mm Hg) and peak vacuum (-122 mm Hg vs -67 mm Hg) applied to the breast were significantly higher than for the teat. CONCLUSION: Breastfed infants are able to remove milk from a teat using only vacuum with a similar tongue movement to that of breastfeeding. This evidence supports the theory that vacuum is a critical factor in the removal of milk from the breast.

Validation of nipple diameter and tongue movement measurements with B-mode ultrasound during breastfeeding.

Infant feeding problems are extremely common during breastfeeding establishment. To objectively assess infant sucking, consistent methods to analyze ultrasound images of the infant's oral cavity are required. We developed and assessed the reliability of an extensive ultrasound measurement protocol by measuring nipple diameter and placement. Midline submental ultrasound scans of 30 term breastfed infants were analyzed by two raters. Nipple diameter, nipple hard-soft palate junction distance and tongue hard-soft palate junction distance were measured on two frames: tongue-up and tongue-down. No evidence of measurement bias was found between raters and inter-rater agreement and consistency scores were high. The changes in nipple diameter and placement were consistent with previous descriptions; however, the diameter of the nipple was not consistent in either position. This method provides objective measurements representative of tongue movement, and further investigation is required to ensure usefulness when examining sucking difficulties.

House mouse abundance and Ross River virus notifications in Victoria, Australia.

OBJECTIVES: The number of emerging and re-emerging infectious diseases is increasing. As such, understanding the fundamental ecology of infectious disease is critical. Short-lived highly fecund amplification hosts are implicated to influence disease prevalence, but few empirical examples exist. We examined the relationship between mouse (Mus musculus) abundance and Ross River virus (RRV) incidence in northwest Victoria, Australia. METHODS: We determined a biologically plausible distribution overlap of M. musculus, humans, and vector mosquitoes in our study region. We compared M. musculus abundance with human RRV notifications seasonally between 1997 and 2000. RESULTS: Trends in M. musculus and RRV were similar during summer, autumn, and summer plus autumn, but unrelated during winter, spring, and winter plus spring, coinciding with the seasonal abundance and relative absence of the vector, Culex annulirostris. CONCLUSIONS: Our results demonstrate a plausible association between M. musculus and RRV incidence, suggesting that short-lived highly fecund amplification hosts may profoundly influence disease transmission. Our results are supported by theoretical studies and empirical evidence from other systems. Further research is warranted to establish a causal relationship between amplification hosts and RRV, and in other infectious disease systems. Implications for the management of infectious disease may exist.