2.1. Patients and Study Design
weight gain, Weight gain
This was a prospective cohort study conducted between January 2019 and June 2022 in the 39-bed level III NICU at Foothills Medical Center in Calgary, Alberta, Canada. The study was approved by the Conjoint Research Ethics Board of the University of Calgary (REB18-0195, date: 2 April 2018). Written informed consent was obtained from mothers before enrollment. Infants born <30 completed weeks gestation and weighing <1500 g to mothers with enough milk supply (≥150% of infant’s daily needs) were on full enteral feeds for more than 2 weeks and that had slow weight gain (<15 g/kg/day, calculated using the average weight as the denominator), despite optimization of energy and protein intakes, were eligible. Optimization of nutritional intakes was achieved by our two neonatal registered dietitians to meet recommended daily intakes of energy intake (110−135 Kcal/kg/day) and protein (4.0−4.5 g/kg/day for infants weighing <1000 g and 3.5−4.2 g/kg/day for infants weighing 1000−1500 g) [The primary outcome of the study was the rate of weight gain in the two weeks after feeding hindmilk. Weight gain (g/kg/day) was calculated using the average 2-point method [(W2 − W1)/([(W2 + W1)/2]/1000) /number of days] (W = weight expressed in grams) [