Intrauterine growth restriction (IUGR) is the term used to describe a condition in which the foetus is smaller than expected
for the number of weeks of pregnancy. Another term for IUGR is foetal growth restriction. Newborn babies with IUGR are often
described as small for their gestational age (SGA).
A foetus with IUGR often has an estimated foetal weight less than the10th percentile. This means that the foetus weighs
less than 90 percent of all other foetuses of the same gestational age.
Causes
Intrauterine growth restriction results when a problem or abnormality prevents cells and tissues from growing or causes
cells to decrease in size. This may occur when the foetus does not receive the necessary nutrients and oxygen needed for growth
and development of organs and tissues, or because of infection. Although some babies are small because of genetics (their
parents are small), most IUGR is due to other causes. Some factors that may contribute to IUGR include the following:
Maternal factors:
- high blood pressure
- chronic kidney disease
- advanced diabetes
- heart or respiratory disease
- malnutrition, anaemia
- infection
- substance abuse (alcohol, drugs)
- cigarette smoking
Factors involving the uterus and placenta:
- decreased blood flow in the uterus and placenta
- placental abruption (placenta detaches from the uterus)
- placenta previa (placenta attaches low in the uterus)
- infection in the tissues around the foetus
Factors related to the developing baby (foetus):
- multiple gestation (twins, triplets, etc.)
- infection
- birth defects
- chromosomal abnormality
IUGR can begin at any time in pregnancy. Early-onset IUGR is often due to chromosomal abnormalities, maternal disease,
or severe problems with the placenta. Late-onset growth restriction (after 32 weeks) is usually related to other problems.
With IUGR, the growth of the baby's overall body and organs are limited, and tissue and organ cells may not grow as large
or as numerous. When there is not enough blood flow through the placenta, the foetus may only receive low amounts of oxygen.
This can cause the foetal heart rate to decrease placing the baby at great risk.
Babies with IUGR may have problems at birth including:
- decreased oxygen levels
- low Apgar scores (an assessment that helps identify babies with difficulty adapting after delivery)
- meconium aspiration (inhalation of the first stools passed in utero), which can lead to difficulty breathing
- hypoglycaemia (low blood sugar)
- difficulty maintaining normal body temperature
- polycythemia (too many red blood cells)
Severe IUGR may result in stillbirth. It may also lead to long-term growth problems in babies and children.
During pregnancy, foetal size can be estimated in different ways. The height of the fundus (the top of a mother's uterus)
can be measured from the pubic bone. This measurement in centimetres usually corresponds with the number of weeks of pregnancy
after the 20th week. If the measurement is low for the number of weeks, the baby may be smaller than expected. An ultrasound
is a more accurate method of estimating foetal size. Measurements can be taken of the foetus' head and abdomen and compared
with a growth chart to estimate foetal weight. The mother’s weight gain is also an indication of a baby's size. Small
maternal weight gains in pregnancy may correspond with a small baby.
Treatment
It is not possible to reverse IUGR, but some treatments may help slow or minimize the effects. Specific treatments will
be decided upon by your G.P. they may include:
- nutrition
Some studies have shown that increasing maternal nutrition may increase gestational weight gain and foetal
growth.
- bed rest
Bed rest in the hospital or at home may help improve circulation to the foetus.
- early delivery
If IUGR endangers the health of the foetus, then an early delivery may be necessary.
Prevention
Intrauterine growth restriction may occur, even when the mother is in good health. However, some factors may increase the
risks of IUGR, such as cigarette smoking and poor maternal nutrition. Avoiding harmful lifestyles, eating a healthy diet,
and getting prenatal care may help decrease the risks for IUGR. Early detection may also help with IUGR treatment and outcome.
For more information ask your midwife or do a search there are many sites that mention it but no support site that we can
find.
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