Overview

Small for gestational age (SGA) is when a neonate is born weighing less than is expected for their gestational age and is defined as having a birth weight less than the 10th percentile for gestational age.

Classification of SGA

Classification	Description
Symmetrical	All growth parameters (weight, length and head circumference) are similarly low. Due to insults suffered in early pregnancy fetal factors e.g. congenital abnormalities, congenital infection, and chromosomal abnormalities
Asymmetrical	Weight, lenght and head circumference are not equally affected. Occurs due to insluts in late pregnancy and is associated with maternal factors e.g. maternal illness and placental insufficiency

• Features suggesting SGA antenatally
  • Fundal height examination
    • A low fundal height suggests SGA
  • Ultrasonography – impaired fetal growth can be assessed by observing, biparietal circumference , abdominal circumference, and femur length
    • Will be all reduced in an neonate suspected to be SGA.
• Features suggesting SGA postnatally
  • Low birth weight for gestational age
  • Measuring weight, length and head circumference to classify SGA (If symmetrically or asymmetrically involved)

Etiology

• Maternal medical disorders
  • Pre-eclampsia
  • Long standing diabetes
  • Chronic kidney disease
  • Cardiovascular disease
  • Pulmonary disease
  • Lupus
  • Severe anemia
  • Sickle cell disease
  • Uterine abnormalities such as bicornuate uterus
  • Malnutrition
• Maternal substance exposure
  • Alcohol
  • Smoking
  • Therapeutic drugs
  • Herbs
• Pregnancy-related factors
  • Multiple pregnancy
  • Placental dysfunction – placental abruption
  • Assisted reproduction
• Fetal factors
  • Chromosomal abnormalities
  • Congenital infection
  • Birth defects

Complications

• Increased risk of fetal death and asphyxia
• Increased risk of infection due to an impaired immune system
• Hypothermia due to reduced fat stores and carbohydrates hence cannot generate energy and heat
• Hypoglycemia due to low carbohydrate stores
• Polycythemia due to chronic intrauterine hypoxia. Presents with a ruddy complexion and contributes to neonatal sluggishness
• Thrombocytopenia and neutropenia due to bone marrow dysfunction
• Coagulopathy due to hepatic dysfunction
• More at risk of meconium aspiration syndrome
• Increased risk of feeding intolerance and/or necrotising enterocolitis

In the long term infants with a history of intrauterine growth restriction may have an increased likelihood of problems during adulthood, including heart disease, high blood pressure, and stroke.

Management

• Routine postnatal care
• Evaluate for cause of SGA – take a maternal and perinatal history, do a TORCHES panel
• Thermal care such as incubator care
• Blood glucose monitoring and correction of hypoglycaemia if noted
• Observe vitals continuously for at least first 48 hours

Well infants may be discharged if:

• Is sucking all feeds every 3-4 hours
• Body temperature is within room temperature
• Weight gain is satisfactory at about 20-30g/day
• Mother can care for infant