Breast milk is universally recognized as the ideal nutrition for preterm newborns, whether orally or enterally. When a mother’s own milk (MOM) is insufficient or unavailable, pasteurized nor human milk (DHM) from human milk banks (HMBs) is recommended by major international health organizations, including the World Health Organization (WHO), the American Academy of Pediatrics (AAP), and the European Society for Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN)^[1][2][3]. The utilization of DHM offers numerous clinical advantages, notably reducing neonatal necrotizing enterocolitis (NEC), promoting better feeding tolerance, and mitigating long-term cardiovascular risk factors in adolescence^[1][4]. A recent Cochrane systemic review further confirmed that, compared with formula feeding, DHM significantly decreases the risk of NEC and improves short-term feeding outcomes in preterm and low-birth-weight infants^[4].

Globally, the establishment of HMBs has expanded rapidly over recent decades. A study from 2020 reported that 572 HMBs were operating across more than 37 countries, providing DHM to approximately 800,000 infants annually^[5][6]. According to the 2023 WHO global preterm birth report, an estimated 13.4 million infants are born preterm each year worldwide, with China continuing to rank second globally in the absolute number of preterm births ^[7]. Despite the high clinical demand for DHM, the establishment and sustainable operation of HMBs in China face persistent hurdles. Although approximately 35 human milk banks have been established across mainland China by 2025, most still struggle with limited donor recruitment and unstable operational models^[8]. A recent study evaluating Chinese mutual-aid milk banks highlighted that fluctuating donor pools and constrained funding remain the primary bottlenecks restricting overall service capacity^[9].

Current literature has delineated the general sociodemographic profiles of human milk donors, such as age, education, parity, and delivery mode—and has explored factors influencing donation volumes^[6][8]. However, most existing studies have focused on healthy, term postpartum women as the primary donor pool, while in-depth investigations into mothers of preterm infants hospitalized in the neonatal intensive care unit (NICU) remain scare. Although recent pilot studies suggest that NICU mothers may represent a highly committed and reliable donor, to verify their actual contributions, donation capacities, and key driving factors, demographic, large-sample, long-term observational data are still required^[10][11][12]. Furthermore, integrated HMB-NICU operational models have rarely been documented in China, and their advantages in ensuring donor stability, optimizing cost savings, and enhancing service sustainability have not been fully validated.

The Xiamen Humanity Human Milk Bank (XMHHMB), affiliated with Xiamen Humanity Women and Children’s Hospital, was established in October 2018. It stands as the only HMB in Fujian Province to maintain continuous operations over the past five years, sustained by institutional financial support from the hospital. Notably, this milk bank remained fully functional during the challenges of the COVID-19 pandemic. A key feature of our facility is that the NICU is staffed by a full-time, certified lactation consultant who provides specialized, proactive breastfeeding and milk expression support to mothers of hospitalized infants. This infrastructure establishes an integrated HMB–NICU management model.

Against this background, this study retrospectively analyzed the characteristics and donation data of 231 human milk donors at the XMHHMB between October 2018 and July 2023. We aimed to characterize this donor population and elucidate the relationships between donor attributes and milk donation volumes, thereby providing empirical data to guide the establishment, management, and long-term sustainability of other HMBs and NICUs.

Study Methodology

Data Collection and Consent

Donor data were extracted retrospectively from the electronic medical and donation records of the XMHHMB. Informed consent was confirmed and verified via telephone communication with all participants. All donors enrolled in this study provided explicit consent for their data to be used for research purposes.

Eligibility and Variables

Medical records of mothers who donated human milk to the XMHHMB between October 20, 2018, and July 24, 2023, were screened for eligibility. To evaluate the correlations between donor characteristics and donation volumes, comprehensive demographic and clinical data were collected. These variables included donor name, age, contact information, education level, parity history, delivery mode, NICU admission status of the newborn, gestational age at delivery, infant birth weight, volume per individual donation. For mothers of twins, the birth weight of the lighter twin was utilized for analysis, as this parameter more critically influences the length of NICU stay and subsequent maternal donation patterns.

Early Lactation Support

At Xiamen Humanity Women and Children’s Hospital, all mothers whose infants were admitted to the NICU, including those who subsequently became milk donors, received standardized, comprehensive lactation support from certified lactation consultants as part of a routine, center-specific protocol. This intervention package included:

•Assessing maternal breastfeeding intentions and educating mothers on the immunological and nutritional importance of breast milk for preterm infants.

• Provide one-on-one breastfeeding counseling within 24 hours postpartum.

• Perform regular follow-up to assess milk production.

• Offer individualized guidance on milk expression.

Calculation of Donation Volume

The total individual donation volume for each mother was calculated as the cumulative sum of all milk volumes recorded across all separate donation sessions throughout her active donor period. The cohort's overall total donation volume was defined as the sum of these individual cumulative volumes across all 231 donors.

Statistical Analysis

Statistical analysis was performed using SPSS version 25.0 software. Categorical data are expressed as frequencies and percentages (%). For continuously distributed data, conforming to a normal distribution, dada are presented as mean±standard deviation (x±s), and comparisons were performed using independent-samples t-tests or one-way analysis of variance (ANOVA) for intergroup and intragroup differences. For non-normally distributed continuous data, variables are expressed as median and interquartile range (M (P25, P75)). Group comparisons for these variables were executed using the Mann-Whitney U test (for two groups) or the Kruskal-Wallis H test (for multiple groups). Statistical significance was defined at P < 0.05.

Results

Relationship between donor characteristics and volume of milk donated

A total of 231 donors were evaluated. The mean age of the cohort was 29.83±4.05 years (range: 17 - 43 years). Parity history and maternal education level did not correlate significantly with total volume of milk donated (P > 0.05). Interestingly, our analysis revealed that mothers who underwent a C-section demonstrated significantly higher donation volumes compared to those who delivered vaginally (median 3,850 mL vs. 2,800 mL, P = 0.011; Table 1). While this finding appears to diverge from some previous literatures^[8], we hypothesize that it reflects the universal, proactive lactation support provided by our full-time certified lactation consultants, who deliver standardized, early counseling and hands-on guidance within 24 hours postpartum regardless of delivery mode. These findings provide preliminary evidence that mothers delivering via C-section can serve as highly productive milk donors when given adequate support.

Table 1: Relationship between human milk donor characteristics and the volume of milk donations.

Relationship between neonatal characteristics and the volume of milk donations

A total of 231 maternal-infant pairs were evaluated. For the two donors who delivered twins, only the lighter infant was indexed for clinical tracking. All newborns survived to discharge, and 127 (54.98%) were admitted to the NICU (Table 2).

No significant difference was observed between the milk volume donated by mothers whose infants required NICU admission and those whose infants were not hospitalized (P = 0.929). However, statistically significant differences were observed across gestational age categories (P = 0.001): mothers who delivered extremely preterm infants (<32 gestational weeks) donated significantly more milk (median 5,000 mL) than those who delivered at later gestational ages.

When stratifying donors by newborn birth weight, a parallel and statistically significant trend emerged (P = 0.043). Mothers of extremely low-birth-weight infants (<1,500 g) donated substantially higher volumes of milk (median 8,000 mL) compared to the higher birth weight cohorts.

Table 2: Relationship between neonatal characteristics and the volume of milk donated.