In a very small number of pregnancies, the baby may not grow as well as we would expect. This is called intrauterine growth restriction (IUGR) and the unborn baby will be described as being “small for gestational age” (SGA). This means that the baby is smaller than expected for the length of pregnancy and for that particular woman. Charts based on your details help us to know what size baby to expect for you. An unborn baby with IUGR should be carefully managed during pregnancy and birth.