Impact of advanced maternal age on neonatal survival of twin small-for-gestational-age subtypes.

Aim: We examined the impact of advanced maternal age (>40 years old) on the survival of twin small-for-gestational-age (SGA) infants, that is, infants who were smaller in size than was expected for the baby's sex, genetic heritage, and gestational age.

Methods: The present study was a retrospective cohort study on twin live births in the USA from 1995 to 1998 inclusive. Two categories of SGA babies were defined: discordant (when only one of a twin pair was SGA) and concordant (when both were SGA).

SGA subtypes and mortality risk among singleton births.

Objectives: To determine whether early mortality (first year of life) risks among small for gestational age (SGA) neonates were similar regardless of SGA subtype based on three chronological classifications (term, preterm and post-term).

Study Design: Retrospective cohort study on all singleton live births in the United States from 1995 to 1999 inclusive. Adjusted risk estimates were computed from logistic regression models using non-SGA infants as the referent.