Neonatal intensive and special care is an expensive and limited health resource. Having a child in hospital is stressful and inconvenient for families, and may result in unbudgeted costs and loss of income; the home environment is most appropriate for normal infant development. For these reasons it is important that babies are discharged from neonatal units as early as is safely possible. Preterm infants take up the majority of neonatal hospital bed-days and our review will focus on this population.

There are three main parameters to consider: physiological maturity, parental readiness and home environment, and administrative/bureaucratic infrastructure. In a critical review of early discharge from the neonatal intensive care unit (NICU) for very-low-birthweight (VLBW) infants, Merritt et al1 summarised what has previously been published about discharge criteria. For physiological maturity, most would agree that adequate suckling to maintain weight gain, respiratory stability with freedom from apnoea, and ability to maintain body temperature in an open cot are important criteria. Despite this general consensus, there is marked variation in length of stay: the average for babies <1.5 kg birth weight discharged home from the 552 hospitals participating in the Vermont Oxford Database in 2005 ranged from ∼40 to ∼80 days (fig 1). Some of this variation reflects different gestational age distribution (fig 2) and some reflects differences in diagnoses and clinical outcomes—for example, chronic lung disease, necrotising enterocolitis requiring surgery, and more than two episodes of sepsis are associated with prolonged hospital stays.2 Some variation is due to different management policies for clinical issues such as apnoea and infant feeding.3 However, differences in the discharge process may also be important, as illustrated by the finding that moderately preterm infants cared for in the Kaiser Permanente Medical Care Program in California were discharged on average 4 days younger than …