A preterm infant is a baby born before 37 weeks of gestation.According to data from the World Health Organization, each year, more than 15 million infants are born preterm worldwide, and about 10% of these or about 1,170,000 preterm infants are born in China (Zou et al., 2014). Because of their physical immaturity, preterm infants have a high incidence of complications such as hypoglycaemia, apnoea, infection, feeding difficulties, necrotizing enterocolitis and anaemia (Caldas et al., 2018). Preterm infants are usually admitted to the neonatal intensive care unit (NICU) after birth. To prevent cross infection, the NICU of children's hospital restricts parents' visits to their children. There are webcams in the ward, and caregivers can use the hospital visiting machine to see their children. Preterm infants can only be discharged when their condition meets the following discharge criteria: stable vital signs; corrected gestational age of 34 weeks; weight greater than 2,000 g along with continuous growth; complete oral feeding; stable temperature and vital signs at room temperature; and if a disease is present, full recovery from the disease or partial recovery until treatment at home is acceptable (Picone et al., 2011). Compared with their peers, preterm children require more intensive care after discharge, which can be challenging and causes considerable stress for the parents and other caregivers (Msall, 2019). The parents of preterm infants often experience more severe negative emotional reactions and psychological pressures than those experienced by the parents of healthy full-term infants, and thus, they require ongoing care and