Growth retardation occurs when a fetus doesn’t develop at a normal rate. It is widely referred to as intrauterine growth restriction (IUGR). The term intrauterine growth retardation is also used.
Children with IUGR are much smaller than other children of the same gestational age. The term is also used for full-term babies who weigh less than 5 lbs., 8 oz. at birth.
There are two forms of growth retardation: symmetrical and asymmetrical. Children with symmetrical IUGR have a normally proportioned body. They are just smaller than most children of their gestational age. Children with asymmetrical IUGR have a normal sized head. However, their body is much smaller than it should be. On an ultrasound, their head appears to be much larger than their body.
IUGR occurs for a number of reasons. There may be an inherited abnormality in the baby’s cells or tissues. The baby could be suffering from malnutrition or low oxygen intake. The mother may have problems with her own health.
IUGR can start at any stage of pregnancy. A number of factors increase IUGR risk. These factors are divided into three categories: maternal factors, fetal factors, and uterine/placental factors. Uterine/placental factors are also referred to as intrauterine factors. They include:
- chronic diseases, such as chronic kidney disease, diabetes, heart disease, and respiratory disease
- high blood pressure
- certain infections
- substance abuse
- birth defects
- chromosome abnormalities
- multiple gestation pregnancy
- decreased uterine blood flow
- decreased blood flow in the placenta
- infections in the tissues around the fetus
A condition known as placenta previa can also cause IUGR. Placenta previa occurs when the placenta attaches low in the uterus.
You may not notice any signs that your baby has growth retardation. Most women are unaware of the condition until they are told during an ultrasound. Some do not find out until after giving birth.
Children born with IUGR are at higher risk of several complications, including:
- low oxygen level
- low blood sugar
- too many red blood cells
- failure to maintain a normal body temperature
- low Apgar score—a measure of infant health at birth
- problems feeding
- neurological problems
IUGR is usually diagnosed during a standard screening ultrasound. Ultrasounds use sound waves to check the development of the baby and your uterus. If your baby is smaller than usual, the doctor may suspect IUGR.
A smaller than normal fetus may be no cause for concern in early pregnancy. Many women are unsure of their last menstrual period. Therefore, the baby’s gestational age may not be accurate. A baby may appear to be small when it is actually the correct size.
When IUGR is suspected in early pregnancy, your doctor will monitor the baby’s growth through regular ultrasounds. If the baby fails to grow properly, the doctor may diagnose IUGR.
An amniocentesis test may be suggested if the doctor suspects IUGR. For this test, the doctor will insert a long, hollow needle through your abdomen into the amniotic sac. Then the doctor takes a sample of the fluid. This sample is tested for signs of abnormalities.
Depending on the cause, IUGR may be reversible.
Before offering treatment, your doctor may monitor the baby using:
- ultrasound—to see how your baby’s organs are developing and check for normal movements
- heart-rate monitoring—to be certain the baby’s heart rate increases as it moves
- doppler flow studies—to make certain that the baby’s blood is flowing properly
Treatment will focus on addressing the underlying cause of IUGR. Depending on the cause, one of the following treatment options may be useful:
Increasing Your Nutrient Intake
This ensures that your baby is getting adequate food. If you have not been eating enough, your baby may not have enough nutrients to grow.
You may be put on bed rest to help improve the baby’s circulation.
In severe cases, an early delivery may be necessary. This allows the doctors to intervene before damage caused by IUGR gets worse. Induced delivery is usually only necessary if the baby has stopped growing entirely or has serious medical problems. In general, doctors prefer to allow the baby to grow for as long as possible before delivery.
There are no known ways to prevent IUGR; however, there are ways to reduce your baby’s risk.
- eating healthy foods
- taking your prenatal vitamins (with folic acid)
- avoiding unhealthy lifestyles (such as drug use, alcohol use, and cigarette smoking)
Children who have a severe form of IUGR may die in the womb or during birth. Children with a less severe form of IUGR may also have complications.
According to the Minnesota Department of Health (MDH), children with low birth weight have an increased risk of:
- learning disabilities
- delayed motor and social development