Influence of donor characteristics on the milk donation volume and microbiological quality of donated human milk in first 3 years of work of the Croatian human milk bank-retrospective observational study.

OBJECTIVES: Donated human milk is the best possible alternative when mother's own milk is not available. The aim of this study is to investigate whether there are differences in the milk donation volumes and microbiological quality of donated milk depending on human milk donors (HMDs) characteristics. METHODS: We analyzed data on the HMDs who donated milk in the first three years of work of human milk bank (HMB) - November 2019 to January 2023. The data on the volume of donated milk in L and suitable microbiological quality assessed by the number and isolated species of bacteria were collected from questionnaires filled out by HMDs and documentation administered by HMB employees and are presented using descriptive and comparative statistics. RESULTS: Two hundred HMDs were included in this study. The majority of them are between 26 and 35 years of age, reside in capital city or the surrounding county, have given birth to a full-term child vaginally, and express surplus milk through a breast pump. Donor mothers of preterm born infants (14.5 %) donated greater quantities, there is statistically significant difference in the median of volume of milk donated (9.6 vs. 6.4, p=0.026). Milk expressed manually shows better results in microbiological quality (median percentage 100 vs. 82 vs. 100, p=0.040), while by comparing other characteristics of the donors, no difference was found between the groups. CONCLUSIONS: It is important to be aware of the characteristics of previous HMDs in order to direct the HMB future promotional and educational activities.

K antigens on neonatal red blood cells blocked by anti-K with titer of 32.

CONCLUSIONS: The blocking of red blood cell (RBC) antigens occurs when potent maternal antibodies bind to antigens on fetal or neonatal RBCs, causing them to be negative when typed with human IgM antisera. This phenomenon is rare; when it does occur, the antibody is usually of a high titer. This reported finding is typically due to anti-D, with rare reports describing false-negative K phenotyping due to blocking by maternal anti-K. We report a case of a potent anti-K with a titer of 32 that blocked K antigens on neonatal RBCs, causing them to phenotype as K-. The neonate also had clinically significant anemia (i.e., hemolytic disease of the newborn) due to the anti-K.