HomePregnancyWhat Is Intrauterine Growth Restriction (IUGR)? - Types, Causes, Symptoms & Treatment

What Is Intrauterine Growth Restriction (IUGR)? – Types, Causes, Symptoms & Treatment


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The term “Pregnancy complications” encompasses a variety of medical conditions. In most cases expecting mothers have manageable issues like fluctuating blood glucose levels (gestational diabetes) and high blood pressure (preeclampsia), etc. These conditions, if diagnosed at an earlier stage, are manageable with the right care and medical interventions.

Intrauterine Growth Restriction (IUGR) is a severe pregnancy complication that directly affects the fetus’ growth inside the womb. The condition approximately affects 10-15% of pregnancies around the world. Although the condition sounds terrifying, it is a manageable complication with proper treatment and care.

This article will explore everything you need to know about IUGR, its causes, symptoms, and the treatments to ensure a healthy delivery.

What is IUGR?

Also known as fetal growth restriction (FGR), IUGR is a condition that affects fetal growth. It means that the fetus isn’t growing at the standard rate with respect to its gestational age. Babies diagnosed with IUGR have a weight that’s below the 10th percentile for their standard gestational age.

However, not every fetus that “measures smaller” than its gestational age gets a diagnosis of intrauterine growth restriction. Every baby has varying growth rates, which means that even though they have a lower birth weight than standard at 15 weeks gestation, things can very well change by the 25 weeks mark.

It is when the fetal growth and fetal weight are consistently low throughout the pregnancy is when the OBGYN confirms a diagnosis of IUGR.

What are the Types of IUGR?

Now that you have an idea about IUGR full form in medical terms, let us walk you through the different types.

There are predominantly three types of intrauterine growth restrictions worth nothing:

Symmetric or Primary – This affects 25% of the babies diagnosed with IUGR. Instead of the birth weight, babies with this type of IUGR have smaller organs than normal. It is often a direct consequence of a genetic disorder or an active infection in the mother’s bloodstream.

Asymmetric or Secondary – This type is marked by a smaller abdomen compared to the normal size of the head and the brain in the developing fetus. It is often witnessed later in the pregnancy and is a consequence of placental complications.

Mixed – This involves a mix of both the above types of IUGR and is often a severe complication that can happen due to poor nourishment of the mother and poor physical well-being of the pregnant mother.

What Causes IUGR?

Understanding or pinpointing one factor out of all the intrauterine growth restriction causes can be challenging. It could be a direct consequence of a fetal, placental, maternal, or genetic factor.

Most pregnant women have this misconception that IUGR is only diagnosed either early on or later in the pregnancy, which isn’t necessarily the case.

The condition might be diagnosed at any point during the pregnancy. However, the period of onset during gestation determines the potential cause.

For example, a diagnosis of IUGR during the first trimester of the pregnancy could be related to genetic disorders or placental complications. Similarly, an IUGR diagnosis during the second or third trimester could stem from maternal complications like active infections, etc.

IUGR, in most cases, isn’t preventable. However, mothers with poor health, malnourishment, lack of prenatal vitamin intake, etc., are at higher risk of developing this pregnancy complication.

Some of the other complications in the mother that are coined as risk factors for IUGR are:

  • Ill habits like smoking, alcohol consumption, doing drugs, etc.
  • History of severe blood infections like rubella or syphilis
  • Anemia
  • Lupus
  • High blood pressure
  • Gestational diabetes
  • Kidney disease
  • Take anti-seizure medications

Being mindful of these potential causes and risk factors might help you adhere to a healthier lifestyle to potentially avoid such a grave complication down the road. Also, in a few cases, intrauterine growth restriction is associated with Down syndrome.

What are the Common Symptoms of IUGR?

Simply knowing the IUGR definition isn’t enough if you don’t have an idea about the symptoms. A lack of or delayed diagnosis can often lead to further (and sometimes irreversible) complications.

Some of the potential symptoms include:

  • Thin or pale skin
  • Malnourished appearance
  • Feeding issues
  • Low blood glucose levels
  • Yellowing of the skin (jaundice)
  • Infection
  • Shortness of breath

It is very difficult (and often impossible) to diagnose IUGR without an ultrasound scan. Only when your doctor assesses and monitors the fetus during the regular scan will they be able to see if the baby’s growth is on track or not.

How is Intrauterine Growth Restriction Diagnosed?

Once you have confirmed your pregnancy, chances are your OBGYN knows which week of your gestation you are currently in.

So, the next time you go for an ultrasound scan, they will measure and assess the length, weight, and other growth parameters of the developing fetus. These parameters are then compared to the standard growth and development chart.

If the difference in the fetal weight and length compared to the standard gestational period is low, it will confirm a diagnosis of IUGR. However, your OBGYN might not give a diagnosis on the first ultrasound appointment and will instead follow up a few weeks later to assess if the condition persists.

If the difference in weight and length is still persistent, that’s when a diagnosis of IUGR is confirmed.

Are there any Treatments for IUGR?

The treatment for IUGR in pregnancy will depend on several factors:

  • How far along are you in your pregnancy
  • The health and development of the fetus
  • What is contributing to the IUGR, etc?

Once your doctor finds an answer to all these questions, they will then focus on closely monitoring the fetus throughout the next few weeks of gestation.

If the issue is due to infections, poor nourishment, etc., you will be treated for the underlying conditions to see if it makes a difference in the steady growth of the fetus.

In severe cases of IUGR where the baby isn’t developing any further, the doctor might suggest an early delivery. It is typically suggested during 37 weeks of gestation and not before that. Cesarean sections are more prevalent in such cases instead of vaginal birth.

If you need an induction for earlier delivery, your doctor will put you on corticosteroids to speed up the formation of the lungs in the fetus so they don’t have any issues with their lungs and breathing once they are born.


  • Do IUGR babies catch up after birth?

Most IUGR babies attain a healthy birth weight and height by the time they reach three years mark. It depends on how well they are being taken care of and ensuring regular check-ins with the pediatrician.

  • Can expectant mothers do something to increase fetal growth?

Although there are no “quick fixes” to support the steady or sudden growth of the fetus, most doctors suggest eating a healthy and balanced diet during pregnancy to support fetal growth. It is always better to discuss your options with your OBGYN for the right medical guidance.

  • Can IUGR be prevented?

IUGR isn’t always a preventable condition. However, you can work on eliminating some of the risk factors that contribute to IUGR, including smoking, drinking alcohol, being malnourished or underweight during pregnancy, etc.


Intrauterine growth restriction isn’t always fatal or damaging to the fetus. In most cases, babies diagnosed with IUGR are born healthy and in their best shape. However, since it is a pregnancy complication, being mindful of it is necessary. Always work as per your doctor’s recommendations and follow the diet they suggest. The best method to deal with IUGR is to focus on prioritizing prenatal care and keeping an eye out for any potential symptoms.

Srujana Mohanty
She is the Managing Editor of Cogito137, one of India’s leading student-run science communication magazines. She's been working in scientific and medical writing and editing since 2018, also associated with the quality assurance team of scientific journal editing. Majored in Chemistry with a minor in Biology at IISER Kolkata, Srujana loves doodling and watching series.


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