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.

Background: Whilst it is inconvenient and time-intensive, predominantly (PP) and exclusively pumping (EP) mothers rely on breast expression to provide milk for their infants and to ensure continued milk supply, yet these populations are poorly understood. Methods: We assessed and characterised Western Australian PP mothers (n = 93) regarding 24 h milk production (MP) and infant milk intake and demographics, perinatal complications and breastfeeding difficulties, the frequencies of which were compared with published general population frequencies. Pumping efficacy and milk flow parameters during a pumping session in PP mothers (n = 32) were compared with those that pump occasionally (reference group, n = 60). Results: PP mothers had a higher frequency of pregnancy complications and breastfeeding difficulties than the general population. Exclusive pumping did not impact the 24 h MP and the amount of milk available to the infant. PP mothers had more milk ejections, longer active flow duration and lower milk removal efficacy ratios; however, responsiveness to pump (time to first milk ejection), total flow duration, time to stop pumping, percentage of available milk removed and comfort parameters were not different to the reference group. Conclusions: Despite the reported challenges, when an effective pump is used, predominant or exclusive pumping does not negatively affect the 24 h MP and the amount of milk available to the infant. Increasing awareness of the impacts of perinatal and breastfeeding complications on women may assist health professionals in early identification of mothers at high risk for early cessation of breastfeeding, escalating early postpartum intervention and targeted breastfeeding support.

Human milk (HM) composition, including metabolic hormones and lipids, is influenced by various factors, including lactation stage and, potentially, infant sex, which may affect infant body composition (BC) development. We aimed to: (a) characterize the longitudinal concentration and intake profiles of HM leptin, adiponectin, insulin, and total lipids; (b) determine if their concentrations and intakes differ by infant sex; and (c) explore the intakes relationships with the development of infant BC. Milk samples (n = 501) were collected from 82 mother–infant dyads during the first 6 months postpartum. Infant 24 h HM intake was measured, and the average cumulative HM component intakes were calculated. The statistical analysis used linear mixed modeling. Intakes of HM leptin, adiponectin, insulin, and total lipids increased to 1 month postpartum and then remained stable. HM intake and total lipids intake but not hormone intakes were positively associated with infant BC (fat-free mass, fat-free mass index, fat mass, fat mass index, percentage fat mass, and fat mass to fat-free mass ratio). HM component concentrations and intakes did not differ by sex. These findings advance our understanding of the temporal nature of HM components, emphasizing the role of infant 24 h HM and total lipids intake in development of infant lean and adipose tissue.

Background/Objectives: Breastfeeding multiple birth infants (MBIs) poses unique challenges that require tailored support; however, research on these mothers’ experiences is limited. This study explored the breastfeeding journeys of Australian mothers of MBIs, highlighting barriers, facilitators, and support needs. Methods: Data were collected via an online survey (May–August 2024) and included quantitative data on breastfeeding initiation, duration, and challenges, as well as qualitative insights into mothers’ experiences. Thematic analysis was used to identify key themes, and statistical analyses were used to compare breastfeeding outcomes by parity. Results: While most mothers (87%) had an antenatal intention to breastfeed, they faced barriers such as latching difficulties (56%), inadequate milk supply (49%), and sore nipples (47%). Preterm births (58%) and neonatal unit admissions delayed the breastfeeding initiation. Most mothers (99%) used electric breast pumps to boost milk supply (68%) and enable expressed breast milk feeding by other caregivers (65% of mothers). While 72% were satisfied with hospital breastfeeding support and some mothers received excellent hands-on support, others felt neglected due to busy staff or conflicting advice. Mothers frequently reported that breastfeeding guidance was geared toward singletons, leaving them unprepared for the challenges of feeding multiples. Mothers’ suggestions for improving care included specialised guidance, better access to lactation support, and in-home practical support to alleviate the burden of feeding and expressing. Additionally, mothers reported that healthcare professionals should be trained to offer practical, non-judgemental support to help mothers navigate the elaborate challenges of breastfeeding MBIs. Conclusions: This study underscores the need for early postpartum support and tailored guidelines to enhance MBI breastfeeding outcomes and maternal-infant well-being.

Background/Objectives: Optimal infant growth is reliant on the sufficient intake of human milk. Studies in animal models speculate that multiparous mothers produce a higher milk yield compared to primiparous mothers. We aimed to examine if there are relationships between consecutive lactations and infant demographics and both maternal 24 h milk production (MP) and infant milk intake (MI). Methods: Lactating mothers 1–6 months postpartum (n = 36; 25 fully breastfeeding (FBF), 11 supplementing with commercial milk formula (partly breastfeeding (PBF)) test-weighed their infants for 24 h during two consecutive lactations and provided demographic information. Twenty-four-hour MP by breast, infant MI (including mothers’ own expressed milk and formula), breastfeeding and expressing frequencies were measured. The statistical analysis used linear mixed modelling accounting for infant birth weight (FBF) or time postpartum (PBF) and for the random effect of the participant. Results: In the FBF group, there were no differences between lactations in terms of MP (p = 0.31) or the infant mother’s own MI (p = 0.14). The birth weight was higher for consecutive lactation infants (p = 0.008). Infant sex was not associated with MP (p = 0.12) or the infant mother’s own MI (p = 0.090). In the PBF group, the breastfeeding frequency (p = 0.042), MP (p = 0.025) and infant mother’s own MI (p = 0.019) were higher in consecutive lactations whilst formula intake was lower (p = 0.004). Conclusions: This study suggests that in fully breastfeeding women, there is no significant effect of consecutive lactation or infant sex on MP or infant MI during established lactation.

Background: Whilst maternal body mass index (BMI) is linked to suboptimal breastfeeding outcomes, maternal body composition has not been assessed with respect to milk production (MP). Methods: Lactating mothers 1–6 months postpartum (n = 281) completed a demographic questionnaire and a 24 h MP measurement using the test-weigh method, enabling the calculation of 24 h MP parameters, breast storage capacity (BSC) and the percentage of available milk removed (PAMR). Body composition was measured with bioimpedance spectroscopy. Linear regression models were used to determine maternal and infant factors associated with MP parameters; structural equation modelling was used to assess the mediating role of BSC. Results: Higher maternal adiposity was associated with lower BSC (p ≤ 0.028), MP (p ≤ 0.003), infant breast milk intake (p ≤ 0.003) and total milk intake (p ≤ 0.026). Higher BSC was associated with higher MP (p < 0.001), with BSC confirmed as a mediator of the relationship between adiposity and MP (67.5%). Mean PAMR was negatively associated with BSC and milk removal frequency (both p < 0.001), and was lower in occasionally pumping compared to breastfeeding only (p = 0.037) and exclusively pumping mothers (p = 0.012). Conclusions: Our findings confirm maternal adiposity as a major contributor to low MP and reveal BSC, which is a measure of glandular tissue volume or breast development, as a mediator between adiposity and MP. This provides a rationale for antenatal lactation assessment of mothers and timely intervention in high-risk mothers to ensure they reach their full lactation potential.