Intrauterine Growth Restriction (IUGR)

Risk Factors

IUGR is more likely to occur in women who are carrying more than one baby or who had a previous baby who was SGA or had IUGR. Certain medical conditions, such as heart, lung, blood, or autoimmune disease, and high blood pressure or anemia can also increase a woman's risk of developing IUGR. So can eating poorly or being underweight before or during pregnancy.

Diagnosis

Since not all babies who are small have IUGR, an accurate diagnosis is important. Initially, this diagnosis relies on correctly determining the baby's age by accurately dating the pregnancy.

Gestational age is initially estimated using the first day of a woman's last menstrual period. Later in the pregnancy (usually between weeks 8 and 13), it is confirmed through an ultrasound. Once a baby's gestational age is known, doctors use it to monitor the baby's growth and compare it with the expected growth rate. If the baby is growing more slowly than expected (sometimes referred to as "small for dates"), doctors will continue to monitor the baby's growth and may perform more tests to determine whether the baby has IUGR.

Monitoring of growth is done in several ways. A measurement called the uterine fundal height helps estimate a baby's size by measuring a mother's belly from the top of the pubic bone to the uterus. Another way to monitor a baby's growth is by using ultrasounds. In fact, IUGR is usually diagnosed through an ultrasound examination.

During an ultrasound, a technician coats the woman's belly with a gel and then moves a probe (wand-like instrument) over it. High-frequency sound waves "echo" off the body and create pictures of the baby on a computer screen. These pictures can be used to estimate the baby's size and weight.

Although these estimates might not be exactly correct, they help health care providers track the baby's growth and determine whether a problem exists. Ultrasounds also can help identify other potential troubles, such as problems with the placenta or low amniotic fluid levels.

Health care providers might also perform some additional tests to diagnose IUGR, such as:

• fetal monitoring to track the baby's heart rate and movements
• screenings for infections
• amniocentesis to help determine the cause of IUGR

If a Baby has IUGR

Once IUGR has been diagnosed, treatment is individualized for each patient depending on the baby's condition and the woman's month of pregnancy.

The baby will be closely monitored, usually with frequent prenatal visits and ultrasounds, to keep track of growth and watch for other potential problems. In some cases, health care providers will recommend inducing labor and delivery early if monitoring shows that a baby has stopped growing or has other problems.

A cesarean section (C-section) might be done if the stress of a vaginal delivery is considered too risky for the baby. Although early delivery might be necessary, the goal is to keep the baby safe in the womb for as long as possible. Sometimes amniocentesis can help determine lung maturity and whether the baby is likely to be able to breathe on his or her own.

Treatment for IUGR also includes addressing the possible causes, including managing any maternal illness and ensuring that the mother eats a healthy and nutritious diet and gains the appropriate amount of weight. Some women are told to avoid aerobic exercise and some are placed on bed rest to improve blood flow to the baby.

Outlook

Unfortunately, babies with IUGR are more likely to have health problems both before and after birth. Those who are born prematurely or are very small at birth are more likely to have problems that result in longer hospital stays. They might also need to receive special care after birth, such as help breathing or medicine to prevent infections.

Other problems that can be associated with IUGR include:

• decreased tolerance for birth, resulting in increased likelihood of C-section delivery
• problems with breathing and feeding
• trouble maintaining body temperature
• abnormal blood cell counts
• low blood sugar level (hypoglycemia)
• decreased ability to fight infection
• increased likelihood of neurological problems
• increased likelihood of stillbirth (dying in the womb before birth)

The long-term effects of IUGR may depend on the condition that caused the problem in the first place.

Coping

When a woman learns that her baby has or might have IUGR, the best thing she can do is to keep all of her prenatal visits and testing appointments and follow her health care provider's recommendations. She also should take care of herself by eating a healthy diet, getting enough rest, and avoiding alcohol, drugs, and tobacco.

Reviewed by: Larissa Hirsch, MD
Date reviewed: July 2011