While most researchers have focused on very premature babies, Michael S. Kramer, M.D., of the Departments of Pediatrics and of Epidemiology and Biostatistics, McGill University, Montreal, a research grantee of the March of Dimes, and colleagues studied the health records of several million U.S. and Canadian babies born as little as one week prematurely. Dr. Kramer and his team were surprised to learn that these babies had a significantly increased risk of dying, especially from asphyxia and infection, compared to full-term babies.
Babies born even mildly premature are more than twice as likely to die in infancy.
Preterm birth is defined as less than 37 full weeks' gestation. Mild prematurity was defined in the study as 34 through 36 completed weeks' gestation, while moderate prematurity was defined as 32 through 34 completed weeks' gestation. Less than 32 weeks gestation is considered very premature. There is a well-known link between lower socioeconomic status and a higher risk of preterm birth. With his PERI grant, Dr. Kramer is examining two possible pathways by which low income and education may result in preterm delivery.