For Clinical Purposes Preterm and Postterm Infants Are Defined As

For clinical purposes preterm and postterm infants are defined as:

A) Preterm before 34 weeks if appropriate for gestational age (AGA) ;before 37 weeks if small for gestational age (SGA) .
B) Postterm after 40 weeks if large for gestational age (LGA) ;beyond 42 weeks if AGA.
C) Preterm before 37 weeks,postterm beyond 42 weeks,no matter the size for gestational age at birth.
D) Preterm,SGA before 38 to 40 weeks;postterm,LGA beyond 40 to 42 weeks.