Association between Prematurity and Autistic Spectrum Disorder

Abstract

Different degrees of prematurity are defined by gestational age (GA), which is calculated from the first day of the mother's last period, or birth weight (BW). One classification based upon BW includes the following categories: • Low birth weight (LBW) – BW less than 2500 g • Very low birth weight (VLBW) – BW less than 1500 g • Extremely low birth weight (ELBW) – BW less than 1000 g Prematurity is also defined by GA as follows: • Late preterm infants: GA between 34 weeks and 36 weeks and 6 days • Very preterm (VPT) infants – GA at or below 32 weeks • Extremely preterm (EPT) infants – GA at or below 28 weeks Neonatal death is defined as an infant death before 28 days of age. Early neonatal deaths occur before the first seven days from birth, and late neonatal deaths occur between 7 and 27 days of age. Infant death is defined as a live birth that results in death within the first year of life (<365 days). The infant mortality rate (IMR) is the number of infant deaths less than one year of age (0 to 365 days of life)