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 an SGA 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.

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. In full term babies, this usually means less than 2,600 grams in weight and/or under 47cm in length.

Although most SGA infants catch up to a height within the normal range by 2 years of age, as many as 10% do not and this can be greater in more severe cases.

There are many reasons why some babies are born small and it is often difficult to find the exact reason why a baby is born SGA. 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 hereditary link in babies who are 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 SGA babies is that they are a lot lighter or shorter than most other babies. Other features of SGA 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 very thin and have poor muscle development.
Metabolic disturbances -Children born SGA 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 SGA 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 smaller in SGA 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.

SGA children may have an increased risk of developing type 2 diabetes, hypertension and cardiovascular disease at a relatively young age later in life.

For further information talk to your doctor.

Last updated: March 2009
CAID/SUEC/HGH016