Small for gestational age (SGA)

Low birth weight

Small for gestational age means that a fetus or an infant is smaller or less developed than normal for the baby's gender and gestational age. Gestational age is the age of a fetus or baby that starts on the first day of the mother's last menstrual period.

Ultrasound is used to find out if a fetus is smaller than normal for their age. This condition is called intrauterine growth restriction. The most common definition of small for gestational age (SGA) is a birth weight that is below the 10th percentile.

Causes for SGA fetus may include:

  • Genetic diseases
  • Inherited metabolic diseases
  • Chromosome anomalies
  • Multiple gestations (twins, triplets, etc)

A developing baby with intrauterine growth restriction will be small in size and can have problems such as:

  • Increased red blood cells
  • Low blood sugar
  • Low body temperature

Information