Fetal Growth Restriction (small babies)

Written By joseph harmon

Fetal Growth Restriction (FGR)

What Is Fetal Growth Restriction?

Fetal Growth Restriction (FGR), sometimes called Intrauterine Growth Restriction (IUGR), occurs when a baby is measuring smaller than expected during pregnancy.

Most commonly, FGR is diagnosed when an ultrasound shows that the baby's estimated weight or abdominal circumference is below the 10th percentile for gestational age.

It's important to understand that not all small babies have a medical problem. Some babies are naturally small because of family genetics. The challenge for your healthcare team is determining whether a baby is simply small or whether the baby is not reaching their full growth potential.

What Causes FGR?

There are many possible causes of fetal growth restriction.

Placental Insufficiency

The most common cause of FGR is a placenta that is not delivering enough oxygen and nutrients to the baby.

Maternal Health Conditions

Certain medical conditions increase the risk of FGR, including:

  • Chronic hypertension

  • Preeclampsia

  • Kidney disease

  • Lupus and other autoimmune conditions

  • Diabetes with vascular complications

  • Antiphospholipid syndrome

Pregnancy-Related Factors

  • Twin or higher-order pregnancies

  • Certain infections during pregnancy

  • Umbilical cord abnormalities

  • Chromosomal or genetic conditions

  • Some fetal birth defects

Lifestyle Factors

Some factors that can affect fetal growth include:

  • Smoking or nicotine use

  • Alcohol use

  • Cocaine or narcotic use

How Is FGR Diagnosed?

FGR is usually diagnosed by ultrasound.

Your provider may evaluate:

  • Estimated fetal weight

  • Abdominal circumference

  • Amniotic fluid volume

  • Placental appearance

  • Umbilical artery Doppler studies

  • Overall fetal anatomy

Because ultrasound estimates are not perfect, your provider looks at trends over time rather than relying on a single measurement.

What Are Doppler Studies?

Doppler ultrasound evaluates blood flow between the placenta and your baby.

Umbilical artery Doppler studies help determine how well the placenta is functioning and can provide important information about the baby's condition. Abnormal Doppler results may indicate decreased placental function and help guide monitoring and delivery decisions.

What Happens After an FGR Diagnosis?

Most patients will undergo additional monitoring, which may include:

  • Growth ultrasounds every 3–4 weeks

  • Non-stress tests (NSTs)

  • Biophysical profiles (BPPs)

  • Doppler studies

  • Amniotic fluid assessment

The purpose of this monitoring is to ensure your baby continues to receive adequate oxygen and nutrients while remaining safely inside the uterus.

Can I Make My Baby Grow Faster?

This is one of the most common questions we hear.

Unfortunately, once FGR develops, there is no proven diet, supplement, vitamin, or activity that reliably reverses it. Research has not shown benefit from special diets, bed rest, or nutritional supplements in otherwise well-nourished patients.

The most important things you can do are:

  • Attend all scheduled appointments

  • Monitor fetal movement

  • Stay hydrated

  • Follow your provider's recommendations

  • Avoid nicotine, alcohol, and recreational drugs

  • Manage chronic medical conditions

Will I Need to Deliver Early?

Sometimes.

The timing of delivery depends on:

  • How small the baby is

  • Doppler results

  • Amniotic fluid levels

  • Gestational age

  • Maternal health conditions

  • Results of fetal testing

Many patients with mild FGR and normal Doppler studies deliver between 38 and 39 weeks. More severe cases or pregnancies with abnormal Doppler studies may require earlier delivery.

What Are the Risks of FGR?

FGR increases the risk of:

  • Stillbirth

  • Preterm birth

  • NICU admission

  • Low blood sugar after delivery

  • Difficulty maintaining body temperature

  • Other newborn complications

The good news is that careful monitoring significantly improves our ability to identify babies who may benefit from earlier delivery.

When Should I Call My Provider?

Contact your healthcare team immediately if you experience:

  • Decreased fetal movement

  • Vaginal bleeding

  • Leakage of fluid

  • Regular contractions

  • Severe headache

  • Vision changes

  • Severe abdominal pain

  • Symptoms concerning for preeclampsia

Key Takeaway

Fetal Growth Restriction can be a stressful diagnosis, but many pregnancies affected by FGR result in healthy babies. The goal of treatment is not simply to make the baby larger—it's to carefully monitor fetal well-being, assess placental function, and determine the safest time for delivery.

At Calhoun Women's Center, we use ultrasound, Doppler studies, and fetal surveillance to closely monitor babies with FGR and develop an individualized plan for every pregnancy.

FAQ

Does FGR mean my baby will be unhealthy?
Not necessarily. Many babies with FGR do very well, especially when the condition is identified early and monitored closely.

Will I need a cesarean section?
Not necessarily. FGR alone is not an indication for cesarean delivery. Delivery recommendations are based on the overall clinical situation.

How often will I need ultrasounds?
Most patients undergo growth ultrasounds approximately every 3–4 weeks, along with additional fetal testing as indicated.

Can I prevent FGR?
Many cases cannot be prevented because they are related to placental function. However, avoiding tobacco and maintaining good prenatal care can reduce risk and improve early detection.

joseph harmon
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