Study population
primary disease, congenital malformation, congenital intrauterine infection
METABOLIC DISEASE, RH HEMOLYTIC DISEASE
This was a prospective, multicenter, randomized controlled study. The subjects were recruited from five tertiary hospitals in China from Mar 1, 2021 to Dec 31, 2021. These five hospitals are composed of Women and Children’s Hospital of Xiamen University, The Third Affiliated Hospital of Guangzhou Medical University, Northwest Women’s and Children’s Hospital, Shengjing Hospital of China Medical University and Peking University Third Hospital, which are located in the north, Northwest, South China, and each hospital has more than 100 NICU beds. The study groups were created according to randomly assigned numbers. All infants who met the standard of inclusive criteria were assigned random numbers and divided into MCT/LCT group or SMOF group. The inclusion criteria were as follows: (1) premature infants with GA < 32 w or BW < 1500 g; (2) estimated duration of PN > 14 days; (3) starting time of PN < 48 h; and (4) premature infants born in or transferred to our hospital within 24 h after birth. The discharge criteria were as follows: (1) the primary disease was cured, and the vital signs were stable; (2) oral feeding and the amount of milk reached 150 mL/kg/d; (3) BW was more than 1800 to 2000 g; and (4) the corrected GA ≥ 36 weeks. Infants with congenital intrauterine infection, congenital malformation, genetic metabolic disease, ABO or Rh hemolytic disease, or who died within 14 days after birth or continuous intravenous ILE ≤ 14 days were excluded.The study is registered with the Chinese clinical trial registry (