You may hear many acronyms during pregnancy. One of these might be IUGR, or intrauterine growth restriction.

If your baby is diagnosed with IUGR, this means their fetal weight is below the 10th percentile for gestational age or the birth weight is under 5 pounds, 8 ounces.

Less than the 10th percentile means the weight is less than 90 percent of all developing babies who are the same gestational age. IUGR happens in 10 to 15 percent of pregnancies. Causes of IUGR include fetal, maternal, placental, or genetic factors.

Although IUGR means that a baby is growing slower or is less developed than expected during the pregnancy, a baby may still be born healthy. IUGR can also be successfully prevented or treated through strategies with the help of your doctor.

Here is more on what to know about the different types of IUGR and what you can do during pregnancy if your doctor diagnoses your baby with IUGR.

There are three types of IUGR:

  • Symmetric or primary. Babies born with this type have smaller internal organs. Almost 25 percent of all cases are symmetric IUGR. This type occurs earlier in pregnancy and may be due to a genetic disorder or infection.
  • Asymmetric or secondary. In this type, the abdomen is smaller while the head and the brain are regular in size. This kind of IUGR typically happens later in pregnancy. Issues like problems with the placenta can cause it.
  • Mixed. This type is mainly seen in low or middle income countries where there are many risks of IUGR.

Another pregnancy term that sounds similar to IUGR is SGA, or small for gestational age.

SGA is when a baby’s weight is under the 10th percentile for the gestational age or a baby who is smaller than is typical after delivery.

SGA is commonly used interchangeably with IUGR, but there are differences between the two conditions.

IUGR is mainly used to highlight the distress a baby is under during the pregnancy. SGA is used mainly to show how big the baby is, and SGA does not mean there may be any development issues.

The most common symptom of IUGR is the baby being smaller than expected during the pregnancy and at birth. A baby with IUGR may show the following symptoms at birth:

  • appears malnourished
  • thin or pale skin
  • breathing difficulties
  • feeding issues
  • low blood sugar
  • body temperature issues
  • appears yellow (jaundice)
  • infection (sepsis)

IUGR during pregnancy can happen for many reasons. It may have a combination of causes.

Causes may be linked to conditions in the:

  • baby (fetal)
  • mother (maternal)
  • genes
  • placenta

IUGR can happen at any time during pregnancy. Doctors believe that if it happens at the beginning of a pregnancy, it is most likely linked to a genetic cause or an issue with the placenta or umbilical cord.

The placenta delivers oxygen and nutrients to your growing baby. Issues that slow this flow can lead to growth and development problems.

Most of the time, IUGR can’t be prevented. However, there are some factors that may increase the risk that your baby will have IUGR, such as if you have a low body weight (under 100 pounds) or were undernourished during pregnancy.

Other factors during pregnancy that may increase the risk of IUGR include:

At the beginning of your pregnancy, your doctors will calculate the gestational age of your baby using ultrasound and the first day of your last menstrual cycle. This is important for diagnosing IUGR if it happens at the beginning of your pregnancy.

Your doctor will also determine the baby’s size by measuring your fundal height. This is the distance from your pubic bone to the top of your uterus.

Your doctor may weigh you at every prenatal appointment, too. If you’re having difficulty gaining weight, your baby may have a higher chance of developing IUGR.

Another scan to help diagnose IUGR is called a doppler flow study. It measures the blood flow to the baby’s heart and other organs. Like an ultrasound, this test uses sound waves to create an image. Doctors use doppler flow studies to check the umbilical cord blood flow to the baby.

During pregnancy, routine screenings for infections such as syphilis can also help predict the risk of IUGR.

What can I do to help if my baby has IUGR?

  • Eat a balanced diet. Ask your doctor or dietitian about the best foods for you and your baby.
  • Stay hydrated by drinking plenty of water and other liquids.
  • If you’re taking any prescription medications, let your doctor know.
  • Quit smoking and avoid secondhand smoke.
  • Quit drinking alcohol completely.
  • Quit all recreational drugs.
  • Attend all your regular and follow-up prenatal appointments.

If quitting alcohol and other substances, including nicotine, is difficult, reach out to your doctor for support. They can give you tools and resources to help you.

Was this helpful?

Managing IUGR depends on its severity, cause, and how early in the pregnancy IUGR was found.

The two most important factors for IUGR are the health of your baby and how far along the pregnancy is. Your doctor will carefully monitor your and your baby’s health with follow-up visits.

A developing baby can be monitored via:

If IUGR is related to slow weight gain, weight loss, or poor diet while pregnant, your doctor may recommend meeting with a dietitian to address concerns about your nutrition and weight.

If there’s a problem with blood circulation to the baby, you may need to stay in the hospital to be monitored, or you may need to be on bed rest at home.

In cases of severe IUGR where the baby is no longer growing or is not getting adequate nutrition and oxygen through the placenta, your doctor may recommend a cesarean birth for early delivery.

Many babies with IUGR may also be small for their gestational age, but they are otherwise completely healthy. If your baby is diagnosed with IUGR, your doctor will recommend the best treatment plan to prevent and manage any adverse effects.

Prenatal care during pregnancy is very important for both you and your baby. You can help prevent IUGR by avoiding risk factors such as smoking or alcohol use during pregnancy.

Any pregnancy can have IUGR, and babies may face both short- and long-term health issues. If your baby is diagnosed with IUGR, you’ll need monitoring during pregnancy and regular appointments with your baby’s pediatrician after the delivery.