Change in vitamin B12 level in breast milk according to the week of delivery in Turkish women

INTRODUCTION: Vitamin B12 is one of the most important micronutrients in breast milk, as a deficiency can lead to growth and developmental retardation in infants. The aim of this study was to investigate differences in the level of vitamin B12 in breast milk in preterm, late preterm, and term groups according to the number of gestational weeks at delivery, and how vitamin B12 content in breast milk changed during the first 28 days of lactation.
METHODS: A total of 30 mothers (n=10 each for preterm, late preterm, and term delivery groups) were included in the study. Breast milk samples were collected from the participants on day 3, 7, and 28 after delivery. The level of vitamin B12 was analyzed in each sample using the Advia Centaur XP autoanalyzer (Siemens Healthineers GmbH, Erlangen, Germany). Analysis of variance (ANOVA) and post hoc Tukey tests were used for group comparisons.
RESULTS: There was a significant difference in the level of vitamin B12 between the 3 groups based on the week of delivery (ANOVA test, p=0.012). In addition, regardless of the number of days of lactation, a significant difference was found between the preterm (954.1±462.8 ng/L) and term (647±253.2 ng/L) groups in the post hoc Tukey pairwise comparison results (p=0.010). The vitamin B12 level in the 28th day breast milk samples was significantly different between the preterm group (1104.1±431.9 ng/L) and the term group (547.1±274.4 ng/L) (p=0.030).
DISCUSSION AND CONCLUSION: In the term delivery group, the highest level of vitamin B12 was seen in the colostrum, and was lower in transition milk and mature milk. In contrast, in the preterm delivery group, mature milk contained a higher level of vitamin B12 than the colostrum. The vitamin B12 level in breast milk in the preterm group was higher on the 28th day of lactation compared with the term group. This may be a compensation mechanism to prevent possible retardation of growth in the preterm group. According to these results, preterm delivery infants do not require additional vitamin B12 supplementation unless there is a pathology of the maternal or infant vitamin metabolism, or there is a problem performing breastfeeding.