Etiology of Neonatal Death—Revisiting Denominators in Perinatal Research

Neonatal mortality accounts for one-half of all deaths among children younger than 5 years.Reducing deaths within the first 28 days of life is a global health priority.Studying the etiology of neonatal death (NND) is complex, as it may arise from 2 sources: in utero pathologies (fetal causes) and perinatal problems such as immaturity and complications of delivery (birth-dependent causes).In practice, these 2 sources cannot be separated. 1The populations at risk for each source are distinct,