Small for gestational age (SGA)

A baby who is born lighter/smaller than it should be for the time he or she has been growing in the womb (its gestational age), is often called a small for gestational age baby, a small for dates baby, or a low birth weight baby. You may also hear that these babies have been affected by Intrauterine Growth Retardation, which is often shortened to IUGR. This means that they have not grown appropriately in the womb.

Normal range
It is estimated that approximately 5% of all newborns are born small for gestational age (SGA) with a birth length and/or weight below the normal range. The exact weight of babies who are considered to be small for their gestational age varies according to how many weeks the mother’s pregnancy lasted. Although most small for gestational age infants catch up to a height within the normal range by 2 years of age, as many as 10% do not.  Babies severely affected at birth are less likely to reach the normal range by two years of age.

Reasons why babies are born small
There are many reasons why babies are born small for gestational age and it is often difficult to find the exact cause. For a foetus to grow normally in the womb, the mother, the foetus and the nutritional link between them (the placenta) need to be healthy. A disturbance to any of these elements can affect foetal growth. In some cases doctors can trace a genetic link in babies who are born small.

Typical problem with children born small
Children born small for their gestational age are not ill, but they do have certain problems, some of which may right themselves and others which may need medical attention for the rest of the child’s life. The most obvious feature of small for gestational age babies is that they are lighter or shorter than most other babies. Other features of small for gestational age children include:

• Feeding problems: you may notice that your baby doesn’t seem to eat very much compared with other babies. This may continue as your child gets older. A poor appetite can add to children’s slow growth and your child may be thin and have poor muscle development.
  
  
• Metabolic disturbances: children born small for gestational age are at an increased risk of developing certain metabolic disorders as they grow up. These include problems with the digestion of glucose, high blood pressure and lipid imbalances, which can lead to diabetes and obesity in later life. For these reasons it is important to keep a close check on your child’s weight and diet.
  
  
• Learning problems: children born small for gestational age are more likely to experience learning difficulties and may have problems with clumsiness and hyperactivity.
  
  
• Hearing and speech problems: because the tube that leads from the ears to the back of the mouth is narrower in small for gestational age babies, it can easily become blocked when your child gets a cold or throat infection. These ear infections can be painful and if they don’t clear up they can make it harder to hear.

Later life
Small for gestational age children may have an increased risk of developing type 2 diabetes, hypertension and cardiovascular disease later in life. Growth hormone
treatment at an early age in small for gestational age children with persistent short stature stimulates catch-up growth, resulting in an adult height within the normal range.

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