Atlas of Neonatal Pathology: Classification of newborn infants by weight and gestation

+ Introduction

+ Support

+ Neonatal pathology

Classification of newborn infants by weight and gestation

Classification

Newborn classification based on gestational age

Preterm (premature) — born at 37 weeks' gestation or less
Term — born between the beginning of week 38 and the end of week 41 of gestation
Post-term (postmature) — born at 42 weeks' gestation or more

Newborn classification based on birth weight

Low birth weight (LBW) — less than 2500 g Very low birth weight (VLBW) — less than 1500 g Extremely low birth weight (ELBW) — less than 1000 g

Newborn classification based on birth weight and gestation is valuable in predicting the outcome. At any gestation the poorest outcome is seen in infants with marked intrauterine growth retardation.

Appropriate for gestational age (AGA) — weight is appropriate for the gestational age
Small for gestational age (SGA) — smaller than expected, the weight falls bellow the 5th percentile for the gestational age
Large for gestational age (LGA) — heavier than expected, the birth weight is above the 95th percentile for the gestational age

Clinical signs

Evaluation of newborns enables to predict complications which may occur during fetal to neonatal transition period. Premature infants are at main risk of organ system immaturity espacially respiratory. Hyperbilirubinemia and hypothermia is a frequent problem, there is an increased risk of infection and sepsis. SGA infants are at high risk of birth asphyxia, there is often transient hypoglycemia and hypothermia even in term hypotrophic infants and increased incidence of cogenital anomalies and intrauterine infections as the underlying condition of growth failure.

Pathology of gestation length

Growth and developement