Generic Database of Very Low Birth Weight Infants

Inclusion Criteria: * Infants inborn at NICHD NRN centers that are: * 401-1000 grams birth weight, and/or * 20 0/7 to 28 6/7 weeks (\<29 weeks) gestational age * Infants enrolled in one or more additional NICHD NRN interventional trials or time-limited observational studies. For infants that do not meet the inclusion criteria above, inclusion and exclusion criteria for the Generic Database are determined by the criteria for the additional trial(s). In these cases, infants that are larger than 1,000 grams and/or older than 29 weeks may be included in the GDB. Exclusion Criteria: * Infants \>1,000 grams birth weight and/or \>29 weeks gestational age Note: These inclusion criteria were changed as of 1/1/2008. Prior to this date, all infants with birth weights between 401 and 1500 grams who are admitted to NRN NICUs within 14 days of birth were included in the database.