IUGR (Intrauterine Growth Restriction | SGA (Small for Gestational Age)
What are SGA| IUGR
Small for Gestational Age (SGA) is a term given to a baby that is born smaller than normal when compared to other babies that had the same number of weeks of pregnancy. SGA babies may be proportionally small, i.e. equally small all over, or they may be of normal height but have a lower weight.
A low birthweight, or small for dates, baby is a baby born with a weight that is inappropriately low for the duration of the pregnancy. For a baby born at term this would be a birthweight less than 2.5kg. A baby born below this weight indicates that growth within the womb has been unsatisfactory and this is called ‘Intrauterine Growth Restriction’ or IUGR.
Why does it occur?
Babies may be born SGA through genetics, both parents are small but more commonly they will be small because of problems during pregnancy. IUGR commonly occurs when the foetus does not receive the necessary nutrients and oxygen needed for proper growth and development of organs and tissues.
How are IUGR & SGA diagnosed?
The diagnosis of IUGR is based on comparison of the baby’s weight centile at birth with the ‘averages’ of all babies born at that number of weeks, however, it is also based upon gender. For example, a male baby born at 32 weeks will be compared to the average of all males babies born at 32 weeks.
A baby is classed as Small for Gestational Age when they are born with a low birth weight, one which is inappropriately low given the length of the pregnancy. For a baby born at term this would be less than 2.5kg.
The inappropriately low weight indicates that the growth of the baby in the womb has been unsatisfactory – hence the name Intrauterine Growth Restriction.
Most babies born too small for their gestational age catch up over the first two or three years of life. However, in about a third, complete catch-up growth does not occur. These children remain small and don’t reach their genetic potential as defined by their parental heights.
The diagnosis of IUGR is based on comparison of the babies’ weight centile at birth, with standards including the baby’s gestational age. Ideally, infant length should also be taken into account.
Signs & Symptoms
Babies with IUGR can often be identified during early pregnancy. Aside from the short stature, IUGR babies may have reflux issues and constipation. They may also have feeding difficulties.
The child who has IUGR, but has not experienced catch-up growth during the early years (before 3 years), will generally remain small for their age. Their final height may be in the region of 157cm (5’2″) for a boy and 144cm (4’9″) for a girl.
Treatment & Support
Many features of IUGR may require medical help and support, so discuss any concerns with your growth specialist, who can then refer your child to another appropriate specialist if necessary.
Babies identified as IUGR/SGA will probably need support with feeding, including high calorie milks and potentially the use of a feeding tube. There can also be a need for medication relating to reflux and constipation. Once the calorie intake has been maximised there may be a need for further treatments such as growth hormone.
There is no definitive way to help your child put on weight, although this can be very worrying. These children are healthy and active, and confrontation over food should be avoided where possible.
Growth hormone has been shown to be beneficial both in the short term, and the long-term, with final height increased by up at 14cm. As a result, GH is now licensed from 4 years of age for children born SGA who fail to show catch-up growth and who are short, both compared to the normal population and their parents.
Around 90% of babies born small for their gestational age will catch up over the first two or three years of life. This can cause a problem for diagnosis of other reasons for the SGA as the medical profession will work with the assumption that the baby will be one of these 90%. Careful observation and monitoring is needed to determine if the IUGR is an indication of another condition such as Silver-Russell Syndrome.
Please consider calling our helpline for support and advice, we can also help put you in touch with other families with the same condition. We also have members of our Facebook Group who may be able to help you.
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