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IUGR In Pregnancy: What Causes It & What are the Symptoms?

Watching a baby grow in the womb is an exciting experience. Most mothers enjoy seeing their baby look bigger on ultrasounds as the weeks pass. Pregnancy apps even compare a baby’s size to fruits or vegetables. But having an IUGR baby is far from exciting. Babies with IUGR don’t grow at a normal rate. 

Here you’ll find the causes and symptoms of IUGR in pregnancy, plus additional information to help you understand this worrisome condition.

Mother receives ultrasound to see if IUGR in pregnancy is present.

What is an IUGR Baby?

An IUGR baby is a baby that suffers from intrauterine growth restriction (IUGR). This condition means the baby isn’t growing properly in the womb. 

Doctors usually diagnose IUGR when the fetus’s weight falls below the 10th percentile for its gestational age.

IUGR is sometimes also called:

  • Fetal Growth Restriction (FGR) – This term is correctly used interchangeably with IUGR.
  • Intrauterine growth retardation (IUGR) – “Restriction” rather than “retardation” has become more common in recent years, because of the negative connotations associated with the latter word.
  • Small for Gestational Age (SGA) – This is closely related but not completely synonymous with IUGR. SGA refers to a fetus or newborn smaller than the typical size for its gestational age (below the 10th percentile). Not all SGA babies have experienced growth restriction.

Many IUGR babies survive and thrive. But IUGR can be dangerous, and a baby born with FGR will often have a prolonged stay at the hospital. It puts the unborn baby at high risk for birth injuries and morbidity. And it’s the second leading cause of perinatal mortality after prematurity.

The Two Types of IUGR

There are two types of IUGR. The first is symmetrical, also known as primary IUGR. It means that all the baby’s body parts and organs are in proportion to each other. 

The second type is asymmetrical IUGR. With this type, the baby has a normal-sized head and brain. But the rest of the body is small in proportion to the baby’s head. 

Causes of IUGR in Pregnancy

Having a small baby doesn’t always mean there’s a problem. Sometimes a fetus is small because its parents are small. But when the baby is an abnormal size because of a medical issue, doctors should be concerned. Something could be preventing the baby from growing. 

These are some general possible causes of IUGR:

  • Lack of nutrients and oxygen (usually the result of problems with the placenta or uterus)
  • Maternal factors, such as chronic health conditions or malnutrition (this is why doctors advise mothers to eat healthy foods!)
  • Fetal factors, like genetic abnormalities or infections

Factors That Can Contribute to IUGR in Pregnancy

Sometimes the exact cause of IUGR in pregnancy is unknown. But certain factors can trigger or contribute to it. 

There are a few risk factors that can contribute to IUGR/fetal growth restriction.

For example, there may be a higher risk of IUGR if:

  • The pregnant woman uses drugs, smokes, or drinks alcohol
  • The fetus or mother has high blood pressure or a heart condition
  • The mother has an underlying condition like diabetes, anemia, kidney disease, or a blood clotting disorder
  • The mother is malnourished, underweight, or has an eating disorder
  • Baby has genetic defects or chromosomal abnormalities 
  • The mother is having twins or triplets
  • There are problems with the placenta or umbilical cord
Woman scared about IUGR in pregnancy.

Intrauterine Growth Restriction Symptoms: Symptoms of Fetal Growth Restriction

Diagnosing IUGR as soon as possible is crucial to the baby’s survival. So how do doctors diagnose IUGR in pregnancy? 

First, they need to make an accurate estimate of when the pregnancy started. That way they will know how old the fetus is and how big it should be at a certain date. They will base the baby’s age on the mother’s last period, and then refine the date with an ultrasound done as early as 6-8 weeks. 

When the mother goes in for periodic appointments, doctors should measure the fetus’s growth. They can use ultrasound images and uterus measurements to estimate its length and weight. This way they can be sure the baby’s growth is on track. They should check for signs and symptoms that the fetus isn’t growing. 

Intrauterine growth restriction signs and symptoms can include:

  • The fundal height is too small. Fundal height is the measurement from the top of the mother’s uterus to her pelvic bone. This measurement can be useful for estimating a baby’s size. But doctors should perform additional tests before diagnosing IUGR in pregnancy. 
  • The baby’s measurements are very low or off growth charts. Growth charts help assess whether a baby is growing at the rate it should. Measurements that are too small can be a sign that the fetus isn’t growing the way it should. 
  • Delayed or stagnant growth. The baby’s growth rate may seem fine at first. But then it begins to slow down or plateau during pregnancy.
  • Decreased fetal movements. The mother may notice the baby isn’t kicking or moving as much as usual. 
  • Decreased amniotic fluid levels. An IUGR baby can have a condition called oligohydramnios and have reduced levels of amniotic fluid. (Did you know that too much amniotic fluid can also be an issue during pregnancy?)
  • Doppler ultrasound abnormalities. Doppler ultrasound measures blood flow in the baby’s vessels. It can reveal abnormalities, like reduced blood flow to certain organs or through the umbilical cord.
  • Fetal distress. The baby may show signs of distress during labor. They might have abnormal heart rate or other complications related to IUGR.

Treatment for IUGR in Pregnancy

Treatment for intrauterine growth restriction depends on what caused it, and how severe it is. Doctors will also consider gestational age, and the mother’s health while creating a treatment plan. 

The main goal of IUGR treatment is to promote fetal growth as much as possible. Another goal is to manage any complications that could come along.

Here are some of the methods doctors might use to make this happen:

  • Nutritional support. Only a nourished mother can provide adequate nourishment for a growing fetus. So a dietitian might get involved to optimize the mother’s nutrition and help her gain weight.
  • Close monitoring. (Regular prenatal check-ups and frequent ultrasound examinations)
  • Increased rest and reduced physical activity. 
  • Medications (such as low-dose aspirin or anticoagulants, to improve blood supply to the fetus).
  • Management of underlying conditions (like high blood pressure or diabetes).
  • Fetal well-being assessments. (Like Non-stress tests (NST) or biophysical profiles (BPP) 
  • Hospitalization (in severe cases so doctors can monitor the mother and baby).
  • Early delivery or C-section delivery. An IUGR baby will almost always need an early delivery. This is because they’re at risk for oxygen deprivation. Also, they often can’t withstand labor well. 

Complications of Intrauterine Growth Restriction

IUGR in pregnancy can have significant negative effects on a developing baby. They are often born with low fetal weight. 

That puts an IUGR baby at higher risk for various complications, such as:

  • Respiratory problems
  • Low blood sugar levels
  • Difficulty regulating body temperature
  • Poor immune function 

Additionally, they may be prone to long-term health issues, including developmental delays. They have an increased risk of chronic diseases (like cardiovascular disorders and diabetes) later in life.

But one of the main concerns about an IUGR baby is that it could suffer oxygen deprivation.

This can lead to birth injuries like:

Meeting with birth injury lawyer.

Legal Help for IUGR Injuries

On occasions, doctors commit negligence while treating an IUGR baby. When that happens, parents may have the right to sue. Pursuing a medical malpractice claim can help them get financial assistance to pay for their newborn’s medical needs. 

Most of the cases we see involve a doctor who failed to take action after the baby already had a diagnosis of IUGR. They didn’t take the signs or symptoms of a fetus not growing seriously enough. An attitude like that can lead to birth injuries—sometimes permanent ones. 

In rare cases, IUGR in pregnancy isn’t properly diagnosed. This can also lead to a lawsuit. Some doctors assume a baby is small because its parents are. But a well-trained doctor will know the difference between normal smallness and IUGR. 

If you believe doctors mishandled IUGR in pregnancy, please contact our birth injury lawyers. We help families recover damages so they can give their children the best care possible. You can schedule a risk-free, no-cost consultation here. 

FAQs About IUGR Causes & Symptoms

What are the risks to a baby born with IUGR?

Babies with IUGR can face a number of risks and health challenges, like hypoxia, hypoglycemia, low birth weight and developmental issues.

Does IUGR go away?

IUGR doesn’t disappear, but with proper care, its effects can be managed.

Does fetal growth restriction cause early labor?

IUGR may increase the risk of preterm birth, but not typically. In some cases, your doctor may want to induce labor early if the baby isn’t growing properly.

What health conditions put me at a higher risk for fetal growth restriction?

Conditions like high blood pressure, diabetes, lupus, anemia, or smoking can raise your risk of IUGR.

How can I prevent intrauterine growth restriction?

Regular prenatal care, a healthy diet, abstaining from drugs, smoking and alcohol, and managing chronic conditions can help reduce the risk.

Can growth-restricted babies catch up?

Yes, growth-restricted babies can catch up in growth, but it varies from child to child. Your doctor can monitor and advise.

How can I increase fetal growth?

There’s no guarantee for things like this, but good nutrition, avoiding harmful substances, and following medical advice may support healthy fetal growth.