Perinatal and laboratory determinants of fortified human milk use: a case-control study

This case-control study compared perinatal and laboratory factors between preterm infants who received unfortified human milk (HM) and those who received HM fortified with FM85®. The sample included 38 low birth weight (LBW) preterm infants admitted to a neonatal intensive care unit between June 2022 and May 2023, excluding those with comorbidities or formula use. Perinatal variables including gestational age, birth weight, head circumference (HC), and mode of delivery were analyzed for associations with fortifier use using chi-squared and Student's t-tests. Laboratory values were compared across nutritional stages using the Kruskal-Wallis and Mann-Whitney tests. Very preterm infants (confidence interval [CI]: 4.02-21.10; P<0.001) and those with LBW (CI: 1.30-5.75; P=0.009) were more likely to receive the fortifier, particularly those with poor weight progression during trophic feeding (CI: 1.12-16.30; P=0.039). Altered HC (CI: 1.49-8.24; P=0.004) and cesarean delivery (CI: 2.24-11.30; P<0.001) were also associated with FM85® use. Both groups showed laboratory abnormalities with neutrophils, initially elevated, decreasing (P<0.0001), while lymphocytes increased (P<0.0001). Red blood cell (P=0.00026) and hemoglobin levels (P=0.00007) worsened. Sodium and calcium levels rose significantly (P<0.0001 for both). HM fortification did not significantly alter most laboratory values, except for red blood cell count. LBW, altered HC, and cesarean delivery were associated with a greater likelihood of fortifier use. Immunological changes occurred even with fortification. Homologous fortifiers may represent a more physiological alternative.