Intrauterine growth restriction (IUGR) is a term used to describe a condition in which the fetus is smaller than expected for the number of weeks of pregnancy. Another term for IUGR is fetal growth restriction. Newborn babies with IUGR are often described as small for gestational age (SGA).
A fetus with IUGR often has an estimated fetal weight less than the 10th percentile. This means that the fetus weighs less than 90 percent of all other fetuses of the same gestational age. A fetus with IUGR also may be born at term (after 37 weeks of pregnancy) or prematurely (before 37 weeks).
Newborn babies with IUGR often appear thin, pale, and have loose, dry skin. The umbilical cord is often thin and dull-looking rather than shiny and fat. Babies with IUGR sometimes have a wide-eyed look. Some babies do not have this malnourished appearance but are small all-over.
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 fetus 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:
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 fetus may only receive low amounts of oxygen. This can cause the fetal heart rate to decrease placing the baby at great risk.
Babies with IUGR may have problems at birth including:
Severe IUGR may result in stillbirth. It may also lead to long-term growth problems in babies and children.
During pregnancy, fetal 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 centimeters 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.
Other diagnostic procedures may include the following:
Management of IUGR depends on the severity of growth restriction, and how early the problem began in the pregnancy. Generally, the earlier and more severe the growth restriction, the greater the risks to the fetus. Careful monitoring of a fetus with IUGR and ongoing testing may be needed.
Some of the ways to watch for potential problems include the following:
Although it is not possible to reverse IUGR, some treatments may help slow or minimize the effects. Specific treatments for IUGR will be determined by your physician based on:
Treatments may include:
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.