Osmolality of a fortified human preterm milk: The effect of fortifier dosage, gestational age, lactation stage, and hospital practices

Abstract Objective The purpose of this study was to evaluate the dose-dependent effect of human milk fortifier (HMF) on the osmolalityof various preterm human milks (PHMs) at different gestational and lactation stages, and with different storage and treatment conditions that are routinely used in neonatal intensive care units (NICUs). Study design Twenty-four mothers who had given birth to their baby before 28 or between 29 and 31 weeks of pregnancy participated in the study after 1–2 weeks or 3–4 weeks breastfeeding after delivery. The study was a prospective, multicenter, comparative, and noninterventional study. Osmolalityof fresh or pasteurizedhuman milk stored at 4 °C was measured (cryoscopy) at baseline, and 24 hours after adding Suppletine ® Human Milk fortifier (SHMF) at 3%, 4%, 4.5%, and 5% (w/v). Results PHM without supplementation had an osmolality(mean ± SD) of 301 ± 8 mOsm/kgH 2 O ( n = 40; 95% CI: [298; 303]). Adding 3–5% SHMF induced a linear increase of osmolality( P r 2 = 0.975). With 4% SHMF, the osmolalitymeasure was 443 ± 13 mOsm/kg H 2 O (95% CI: [439–447]). Neither a 24-hour storage at 4 °C nor pasteurizationinduced a modification of osmolalitycompared to the fresh samples. Conclusion Whatever the origin and quality of milk as well as hospital practices, adding up to 4% (w/v) SHMF to PHM increases its nutritional quality and osmolalitywithout exceeding 450 mOsm/kgH 2 O, which is generally recognizedas safe.