Milk microbiome transplantation: recolonizing donor milk with mother's own milk microbiota

Donor human milk (DHM) provides myriad nutritional and immunological benefits for preterm and low birthweight infants. However, pasteurization leaves DHM devoid of potentially beneficial milk microbiota. In the present study, we performed milk microbiome transplantation from freshly collected mother's own milk (MOM) into pasteurized DHM. Small volumes of MOM (5%, 10%, or 30% v/v) were inoculated into pasteurized DHM and incubated at 37 °C for up to 8 h. Further, we compared microbiome recolonization in UV-C-treated and Holder-pasteurized DHM, as UV-C treatment has been shown to conserve important biochemical components of DHM that are lost during Holder pasteurization. Bacterial culture and viability-coupled metataxonomic sequencing were employed to assess the effectiveness of milk microbiome transplantation. Growth of transplanted MOM bacteria occurred rapidly in recolonized DHM samples; however, a greater level of growth was observed in Holder-pasteurized DHM compared to UV-C-treated DHM, potentially due to the conserved antimicrobial properties in UV-C-treated DHM. Viability-coupled metataxonomic analysis demonstrated similarity between recolonized DHM samples and fresh MOM samples, suggesting that the milk microbiome can be successfully transplanted into pasteurized DHM. These results highlight the potential of MOM microbiota transplantation to restore the microbial composition of UV-C-treated and Holder-pasteurized DHM and enhance the nutritional and immunological benefits of DHM for preterm and vulnerable infants. KEY POINTS: • Mother's own milk microbiome can be successfully transplanted into donor human milk. • Recolonization is equally successful in UV-C-treated and Holder-pasteurized milk. • Recolonization time should be restricted due to rapid bacterial growth.

Sampling Procedures for Estimating the Infant Intake of Human Milk Leptin, Adiponectin, Insulin, Glucose, and Total Lipid

Limited attention is given to the efficacy of protocols for the estimation of infant intake of milk components when investigating their impact on infant outcomes. We compared the actual measured intake of human milk components with estimations derived from 15 protocols to determine the most reliable approach for estimating intake of HM leptin, adiponectin, insulin, glucose, and total lipid. Twenty mothers who were 3-5 months postpartum completed a 24 h milk profile study with pre-/post-feed milk samples collection. The true infant intake (control group) based on 24 h milk intake (MI) was compared to estimated infant intakes using concentrations from five sampling protocols that were multiplied by one of true infant MI, considered mean MI (800 mL), or global mean MI (766 mL). The mean measured concentrations of six samples (three sets of pre- and post-feed samples, from morning (06:00-09:00), afternoon (13:00-16:00), and evening (19:00-22:00)) multiplied by the true infant MI, mean considered MI, and global mean MI produced the most accurate estimates of infant intake of these components. Therefore, in the absence of 24 h measurements and sampling, a sampling protocol comprising three sets of pre-/post-feed samples provides the most reliable infant intake estimates of HM leptin, adiponectin, insulin, glucose, and total lipid.

Causes of Low Milk Supply: The Roles of Estrogens, Progesterone, and Related External Factors

Low milk supply (LMS) poses a significant challenge to exclusive and continued breastfeeding, affecting ∼10% to 15% of mothers. Milk production is intricately regulated by both endocrine and autocrine control mechanisms, with estrogens and progesterone playing pivotal roles in this process. In addition to endogenously produced hormones, external substances capable of interfering with normal hormonal actions, including phytoestrogens, mycoestrogens, synthetic estrogens, and hormonal contraceptives, can influence milk production. The effects of these extrinsic hormones on milk production may vary based on maternal body mass index. This comprehensive review examines the multifaceted causes of LMS, focusing on the involvement of estrogens, progesterone, and related external factors in milk production. Furthermore, it investigates the interplay between hormonal factors and obesity, aiming to elucidate the endocrine mechanisms underlying obesity-associated LMS. Insights from this review provide valuable perspectives for developing interventions to improve milk production and address the challenges associated with LMS.

Circadian Variation in Human Milk Hormones and Macronutrients

There is an inadequate understanding of the daily variations in hormones and macronutrients in human milk (HM), and sample collection protocols vary considerably from study to study. To investigate changes in these milk components across 24 h, 22 lactating women collected small milk samples before and after each breastfeed or expression from each breast. Test weighing was used to determine the volume of HM consumed in each feed. The concentrations of leptin, adiponectin, insulin, fat, and glucose were measured, and the intakes were calculated. A linear mixed model was fitted to assess within-feed and circadian variation in HM feed volume and concentration, and intakes of several components. The average infant intake of HM was 879 g/24 h. Significantly higher pre-feed concentrations were found for adiponectin and glucose and lower post-feed concentrations were found for insulin and fat. Significant circadian rhythms were displayed for leptin, adiponectin, insulin, glucose (both concentration and intake), fat concentration, and milk volume. These findings demonstrate the necessity for setting up standardised and rigorous sampling procedures that consider both within-feed and circadian variations in HM components to gain a more precise understanding of the impacts of these components on infant health, growth and development.

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.

The Impact of Gestational Diabetes Mellitus on Human Milk Metabolic Hormones: A Systematic Review

Gestational diabetes mellitus (GDM) is a common pregnancy complication with short- and long-term health consequences for the infant and mother. Breastfeeding is the recommended mode of feeding as it offers an opportunity to reduce the risk of GDM consequences, likely partially mediated through changes in human milk (HM) composition. This review systematically reviewed 12 identified studies that investigated the impact of GDM on concentrations of HM metabolic hormones. Meta-analysis was not possible due to significant heterogeneity in study designs and hormone measurement techniques. The risk of bias was assessed using the National Institute for Clinical Excellence (NICE) tool. The methodological qualities were medium in half of the studies, while 25% (3/12) of studies carried a high risk of bias. Significant relationships were reported between GDM and concentrations of HM ghrelin (3/3 studies), insulin (2/4), and adiponectin (2/6), which may play an integral role in infant growth and development. In conclusion, preliminary evidence suggests that GDM may alter HM metabolic hormone concentrations; however, these relationships may be limited to the early lactation stage.

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.

Delayed secretory activation and low milk production in women with gestational diabetes: a case series

Background

Gestational diabetes mellitus (GDM) is major pregnancy complication that is associated with short- and long-term consequences for both mother and infant, including increased risk of diabetes later in life. A longer breastfeeding duration has been associated with a reduced risk of diabetes, however, women with GDM are less likely to exclusively breastfeed and have shorter breastfeeding duration. While the timing of breastfeeding initiation and milk removal frequency affects subsequent breastfeeding outcomes, little is known about early infant feeding practices and milk production in women with GDM. This case series offers detailed prospective breastfeeding initiation data, as well as the first report of objective measures of milk production in women with GDM.

Case presentation

In this case series, we present the early infant feeding practices of eight women with GDM that gave birth at term gestation. Women recorded the timing of initiation of breastfeeding and secretory activation, as well as their breastfeeding, expression and formula feeding frequencies on postpartum days 1, 7 and 21. Measurement of 24 h milk production volume was performed at 3 weeks postpartum using the test weight method. We observed a delayed first breastfeed (> 1 h) in 6 (75%) cases, formula use in hospital in 5 (63%) cases and delayed secretory activation in 3 (38%) cases. At 3 weeks postpartum, 2 cases had measured milk productions that were insufficient to sustain adequate infant weight gain.

Conclusions

Our data suggest that despite early and frequent milk removal, women with GDM are at greater risk of delayed secretory activation and low milk supply. Cohort studies that consider co-morbidities such as obesity are needed to determine the lactation outcomes of women with GDM.

Human Milk Macronutrients and Bioactive Molecules and Development of Regional Fat Depots in Western Australian Infants during the First 12 Months of Lactation

We investigated associations between intakes of human milk (HM) components (macronutrients and biologically active molecules) and regional fat depots development in healthy term infants (n = 20) across the first year of lactation. Infant limb (mid-arm and mid-thigh) lean and fat areas were assessed by ultrasound imaging at 2, 5, 9 and 12 months of age. Concentrations of HM total protein, whey protein, casein, adiponectin, leptin, lysozyme, lactoferrin, secretory IGA, total carbohydrates, lactose, HM oligosaccharides (total HMO, calculated) and infant 24-h milk intake were measured, and infant calculated daily intakes (CDI) of HM components were determined. This pilot study shows higher 24-h milk intake was associated with a larger mid-arm fat area (p = 0.024), higher breastfeeding frequency was associated with larger mid-arm (p = 0.008) and mid-thigh (p < 0.001) fat areas. Lysozyme (p = 0.001) and HMO CDI (p = 0.004) were time-dependently associated with the mid-arm fat area. Intakes of HM components and breastfeeding parameters may modulate infant limb fat depots development during the first year of age and potentially promote favorable developmental programming of infant body composition; however, further studies are needed to confirm these findings.

Human Milk Metabolic Hormones: Analytical Methods and Current Understanding

Human milk (HM) contains a wide array of peptide hormones including leptin and adiponectin, which are involved in the regulation of infant growth and development. These essential hormones might play an important role in the regulation of metabolic reprogramming of the new-born infant. However, HM hormone studies are sparse and heterogeneous in regard to the study design, sample collection, preparation and analysis methods. This review discussed the limitations of HM hormone analysis highlighting the gaps in pre-analytical and analytical stages. The methods used to quantify HM metabolic hormones (leptin, adiponectin, ghrelin, insulin, obestatin, resistin and apelin) can be classified as immunoassay, immunosensor and chromatography. Immunoassay methods (ELISA and RIA) have been predominantly used in the measurement of these HM hormones. The relative validity parameters of HM hormones analysis are often overlooked in publications, despite the complexity and differences of HM matrix when compared to that of plasma and urine. Therefore, appropriate reports of validation parameters of methodology and instrumentation are crucial for accurate measurements and therefore better understanding of the HM metabolic hormones and their influences on infant outcomes.

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.

Impact of Nipple Shield Use on Milk Transfer and Maternal Nipple Pain

Background: Nipple pain is a common cause of early cessation of breastfeeding. A nipple shield (shield) is often used to improve breastfeeding comfort. There are concerns that shield use may limit milk transfer. The aims of this study were to determine whether shield use reduces milk transfer and maternal nipple pain. Methods: A within-subject study of two groups of breastfeeding dyads (infants <6 months) was conducted; Control Group (CG): no breastfeeding difficulties; Pain Group (PG) shield used for nipple pain. There were two monitored sessions where shield use was randomized. Test weights and pain questionnaires were completed, and percentage of available milk removed (PAMR) was calculated. Results: Twenty-five PG (6 ± 4 postnatal weeks) and 34 CG (9 ± 6 postnatal weeks) had similar 24-hour milk production (PG: 676 ± 239 mL, CG: 775 ± 162 mL, p = 0.083). PG mean milk transfer volume and PAMR did not differ with shield use (no shield: 46 mL, 59%; shield: 40 mL, 53%, volume p = 0.38, PAMR p = 0.64). CG mean volume and PAMR were reduced with shield use (no shield: 65 mL, 64%; shield: 31 mL, 33%, volume p < 0.001, PAMR p < 0.001). PG pain scores were similar with and without shield use (Visual Analog Scale p = 0.44, McGill p = 0.97). Conclusions: Shield use did not impact either milk production or milk transfer in breastfeeding women experiencing nipple pain.

Altered sucking dynamics in a breastfed infant with Down syndrome: a case report

BACKGROUND

The health and developmental advantages of human milk and breastfeeding are particularly important for infants with Down syndrome. However, they typically have shorter breastfeeding duration due to sucking issues that are not well understood. This case report describes serial measures of milk transfer volumes, sucking dynamics and tongue movement in a breastfeeding infant with Down syndrome. Management of maternal milk production enabled feeding of only breast milk until maturation of breastfeeding skills and the achievement of full breastfeeding by 6 months.

CASE PRESENTATION

The mother of a term infant with Down syndrome and no associated health complications presented with concerns regarding adequacy of milk removal at the breast and low milk supply. We monitored sucking dynamics during breastfeeding by measuring intraoral vacuum strength, nutritive and non-nutritive suck rates and burst durations, and tongue movement using submental ultrasound. Breastfeeds were monitored at 4, 10, 14, 19 and 24 weeks, and maternal 24 h milk production was measured at 4, 10 and 24 weeks postpartum. We observed a weaker suck strength and shorter nutritive suck duration, and atypical tongue movement up to 19 weeks, with low milk transfer volumes. Regular breast expression was effective in increasing maternal milk production, providing expressed milk for all complementary feeds. Full breastfeeding was achieved by 6 months when reference sucking values were observed.

CONCLUSIONS

This case report illustrates that infants with Down syndrome may have low intraoral vacuum and limited nutritive sucking that persists for several months, likely due to delayed oro-motor development. In the absence of effective sucking human milk feeding can continue when milk production is stimulated with frequent and adequate breast expression. It is possible for infants with Down syndrome and no associated health complications to eventually establish full breastfeeding. Mothers that wish to breastfeed their infant with Down syndrome require anticipatory guidance and continuing lactation and family support.

Gastric emptying of different meal volumes of identical composition in preterm infants: a time series analysis

BackgroundPreterm infants' meals typically progress to higher volumes over time. Knowledge of gastric emptying (GE) responses to differing meal volumes may inform enteral feeding management. We examined the effect of meal volume and composition on preterm GE.MethodsForty infants were studied at 33.3±1.4 (29.7-35.6) weeks postmenstrual age when fully enteral fed (target 150 ml/kg/day). Intraindividual comparisons of GE were made for paired meals of 100% and 75% prescribed volume and identical composition of mother's own milk (n=21) and pasteurized donor human milk (n=19). Serial stomach ultrasound images were used to calculate gastric residual volumes (GRVs) and remaining meal proportions (% meal).ResultsGE was faster in the early postprandial period and slowed over time (P<0.001). Reduced volume meals had slower GE rates and lower GRV (P<0.001). Serial postprandial % meal was similar between reduced and full volume meals (P=0.41). Higher milk casein concentration was associated with slower GE (P=0.04). Complete gastric emptying (GRV=0 ml) was more common in infants fed at 3 h intervals compared with those fed every 2 h (P=0.002).ConclusionEarly postprandial GE is more rapid for larger meal volumes. Stable preterm infants may tolerate feeding of a 3 h meal volume at shorter intervals.

Impact of Preterm Birth on Glucocorticoid Variability in Human Milk

BACKGROUND

Preterm birth is a stressful event for both the mother and infant. Whereas the initiation of breastfeeding is important for preterm infant health, little is known of the glucocorticoid hormones (cortisol and cortisone) in human milk following preterm birth. Research aim: The aim of this study was to investigate the relationship between human milk glucocorticoid concentrations and preterm birth.

METHODS

Human milk was sampled weekly for up to 6 weeks from 22 women who delivered a preterm infant at 28 to 32 weeks' gestation. Human milk was analyzed for total and free cortisol and cortisone concentrations using liquid chromatography-tandem mass spectrometry.

RESULTS

Milk sampled from mothers of preterm infants had more cortisone than cortisol ( p < .001), with a strong correlation between both hormones ( p = .001, r = .85). The cortisone was significantly higher in the milk of mothers who delivered infants after 30 weeks compared with those who delivered before 30 weeks of gestation ( p = .02). Glucocorticoid concentrations did not change over the sampling time (weeks 1 to 6 postpartum) and did not differ by infant gender.

CONCLUSION

Glucocorticoids were present in all milk samples following preterm birth. Cortisone concentration tended to be higher in those who delivered after 30 weeks' gestation but did not increase further over the weeks following birth.

Case report of nipple shield trauma associated with breastfeeding an infant with high intra-oral vacuum

BACKGROUND

Nipple pain is associated with early cessation of breastfeeding and may be caused by high intra-oral vacuum. However identification of high intra-oral vacuum is typically restricted to the research setting. This is the first reported case of an infant with high intra-oral vacuum that was clinically identified through a specific pattern of nipple trauma associated with nipple shield use. Knowledge of clinical signs associated with high intra-oral vacuum may facilitate early recognition of this unusual breastfeeding challenge.

CASE PRESENTATION

The mother of an exclusively breastfed 3 month old infant had severe bilateral nipple pain with minimal trauma that persisted from birth. The nipples were not misshapen immediately after breastfeeding and adjustments to infant attachment at the breast did not attenuate the pain. Examination of the infant's oral anatomy was unremarkable with no ankyloglossia present. Microbiological cultures of nipple swabs and breast milk were negative for bacterial and fungal growth, and prescribed antimicrobial treatments did not reduce the nipple pain. Mild blanching and erythema of the nipples were occasionally observed, and were not consistent with nipple vasospasm. Nipple shields were used regularly as they modified the pain, although this resulted in blisters that corresponded with the nipple shield holes. Measurement of infant intra-oral vacuum during breastfeeding confirmed intra-oral vacuum up to 307 % higher than reference values. Breastfeeding gradually became less painful, and after 6 months was completely comfortable.

CONCLUSIONS

High intra-oral vacuum is difficult to assess in the clinical setting and is likely an under-reported cause of early weaning that is not well understood. This original case report highlights high intra-oral vacuum as at differential diagnosis to be considered by health professionals when evaluating mothers experiencing strong nipple pain during the initiation of breastfeeding. A clinical screening tool is needed to enable prompt identification of these infants.

Influences on breastfeeding outcomes for healthy term and preterm/sick infants

OBJECTIVE

This study investigated breastfeeding outcomes and factors associated with duration of breastfeeding in cohorts of healthy term and sick/preterm infants.

STUDY DESIGN

Follow-up was conducted of 87 sick/preterm and 92 term healthy infants during the 9 months following discharge from two Western Australian hospitals.

RESULTS

When corrected for gestational age, breastfeeding duration did not differ between the entire cohort of sick/preterm and term healthy groups. Multivariable analysis showed that early cessation of breastfeeding was more likely for infants born at <33 weeks of gestation (hazard ratio [HR ]=2.05, 95% confidence interval [CI]=1.14-3.69), mothers who had previously breastfed for <6 months (HR=3.67, 95% CI=2.12-6.37), and for mothers who perceived breastfeeding to be important rather than very important (HR=2.58, 95% CI=1.59-4.20).

CONCLUSIONS

Maternal perceptions of breastfeeding as "important" rather than "very important" and previous breastfeeding duration of <6 months are negatively associated with breastfeeding duration; these factors can be identified and addressed during pregnancy and in the postnatal period. Preterm infants born at <33 weeks of gestation have a shorter breastfeeding duration than those born at a later gestation.