During pregnancy, regular ultrasound scans help monitor your baby’s growth and development. However, sometimes a scan may show that your baby is smaller than expected for the current stage of pregnancy. This may indicate a condition known as Fetal Growth Restriction (FGR), previously called Intrauterine Growth Restriction (IUGR).
FGR can be detected during early or late pregnancy and requires careful evaluation to understand the possible causes and determine the appropriate monitoring and care.
In this blog, Dr. Archana Kankal, Director OBGY at Momstory, Nagar Road, explains the causes of fetal growth restriction, its risk factors, and how it is managed during pregnancy.
What Is Fetal Growth Restriction (FGR)?
Fetal Growth Restriction is a condition in which a baby does not grow as expected inside the womb. It is often suspected when the estimated fetal weight on an ultrasound is below the expected range for the baby’s gestational age.
An estimated fetal weight below the 10th percentile is commonly used to identify a baby who is small for gestational age and may need further assessment for FGR. A weight below the 3rd percentile is a stronger indicator of significant growth restriction.
FGR can be broadly classified into two categories:
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Early-onset FGR: Detected before 32 weeks of pregnancy. It may be associated with more significant underlying conditions and requires close monitoring.
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Late-onset FGR: Detected at or after 32 weeks of pregnancy. It is more commonly identified during the later stages of pregnancy.
The timing of diagnosis, ultrasound findings, and overall maternal and fetal health help determine the next steps in care.
What Causes Fetal Growth Restriction During Pregnancy?
Several factors can affect a baby’s growth in the womb. Identifying the underlying cause helps the obstetrician plan appropriate monitoring and management.
1. Maternal High Blood Pressure
High blood pressure during pregnancy can affect blood flow to the placenta. When the placenta cannot deliver sufficient oxygen and nutrients to the baby, fetal growth may be affected.
Women with hypertension during pregnancy may require closer monitoring of both their blood pressure and the baby’s growth.
2. Placental Problems
The placenta supplies oxygen and nutrients essential for the baby’s development. If it does not function effectively, the baby may not receive the support needed for normal growth.
Placental insufficiency and certain placental abnormalities can be associated with FGR. A low-lying placenta or placenta previa may require assessment, but these conditions do not automatically mean that fetal growth restriction will occur.
3. Maternal Nutritional Factors
A mother’s nutritional status and overall weight gain during pregnancy can influence fetal growth. An inadequate intake of essential nutrients may contribute to poor growth in some cases.
A balanced diet containing sufficient protein, vitamins, minerals, and other essential nutrients is important throughout pregnancy. Recommended weight gain varies depending on the mother’s pre-pregnancy BMI and individual circumstances, so there is no single target that applies to every pregnant woman.
4. Diabetes During Pregnancy
Gestational diabetes is often associated with a larger-than-average baby, particularly when blood sugar levels are poorly controlled. However, fetal growth restriction can also occur in some pregnancies complicated by diabetes, especially when there are associated vascular or placental problems.
Blood sugar monitoring and appropriate treatment are important for supporting maternal and fetal health.
5. Genetic or Structural Abnormalities
In some cases, particularly when growth restriction is detected early in pregnancy, genetic conditions or structural abnormalities in the baby may be contributing factors.
Depending on the ultrasound findings and pregnancy history, the obstetrician may recommend additional investigations to understand the cause.
How Is Fetal Growth Restriction Detected?
FGR is usually identified through pregnancy ultrasound scans and further assessment when needed.
Your obstetrician may recommend:
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Growth scans: To estimate the baby’s weight and assess growth over time.
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Doppler ultrasound: To evaluate blood flow in selected blood vessels, including those supplying the baby and placenta.
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Maternal blood pressure monitoring: To identify or manage hypertension during pregnancy.
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Blood sugar testing: To check for gestational diabetes.
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Additional investigations: If early growth restriction or other ultrasound findings suggest a possible underlying condition.
Certain first-trimester screening markers and uterine artery blood-flow measurements may also help assess the risk of placental complications in selected pregnancies. These tests estimate risk; they cannot predict every case of FGR.
Can Fetal Growth Restriction Be Treated?
Management depends on the cause of FGR, the stage of pregnancy, the baby’s condition, and the severity of growth restriction.
Although there is no treatment that can reliably reverse every case of FGR, appropriate care can help monitor the baby’s well-being and reduce the risk of complications.
1. Maintain a Balanced, Nutritious Diet
Eating a balanced diet with adequate protein and essential nutrients supports maternal health and fetal development. If nutritional deficiencies or inadequate dietary intake are identified, your doctor may recommend dietary changes or supplements.
Protein powders and nutritional supplements should only be taken when advised by your healthcare professional.
2. Keep Blood Pressure and Blood Sugar Under Control
Managing maternal health conditions is an important part of pregnancy care. If you have high blood pressure or gestational diabetes, follow your prescribed treatment plan and attend recommended follow-up appointments.
3. Follow the Recommended Monitoring Schedule
Your obstetrician may advise regular growth scans, Doppler studies, and other assessments to monitor the baby’s development and blood flow.
The frequency of these tests depends on the severity of FGR and the findings of previous assessments.
4. Take Medication Only When Prescribed
In selected pregnancies, your doctor may prescribe medication such as low-dose aspirin to reduce the risk of certain placental complications. Its use depends on individual risk factors and is generally considered for prevention rather than as a treatment for established FGR.
Do not start aspirin or any other medication without consulting your obstetrician.
5. Plan the Timing of Delivery
When growth restriction is significant or monitoring suggests that the baby may be at risk, your obstetrician may recommend delivery before the due date.
The timing depends on the baby’s growth, Doppler findings, gestational age, and overall clinical assessment. Timely delivery can be essential when continuing the pregnancy poses a greater risk than birth.
Can Fetal Growth Restriction Be Prevented?
Not every case of FGR can be prevented, as some cases are linked to placental dysfunction or underlying fetal conditions. However, appropriate antenatal care can help identify risk factors and support early intervention where possible.
To support a healthy pregnancy:
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Attend all recommended antenatal appointments.
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Follow a balanced and nutritious diet.
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Monitor blood pressure and blood sugar as advised.
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Complete recommended ultrasound scans and other investigations.
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Take prescribed medication as directed.
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Discuss any concerns about your baby’s growth with your obstetrician.
Early identification and consistent monitoring are important for managing FGR and making informed decisions about pregnancy care.
When Should You Consult Your Gynecologist?
If your ultrasound report indicates that your baby’s estimated weight is lower than expected, do not panic. A smaller estimated weight does not always mean that the baby has FGR. Your obstetrician will consider the baby’s growth pattern, gestational age, Doppler findings, and other clinical factors before making a diagnosis.
Seek prompt medical advice if you notice reduced fetal movements or experience any other concerning symptoms during pregnancy.
Fetal Growth Restriction: The Importance of Timely Care
Fetal Growth Restriction requires careful assessment and individualised management. While nutrition and control of maternal health conditions are important, they cannot resolve every underlying cause of restricted fetal growth.
Regular ultrasound scans, Doppler monitoring when indicated, antenatal check-ups, and timely delivery when necessary help the medical team make decisions focused on the baby’s safety.
Momstory, Nagar Road, provides antenatal care and pregnancy monitoring to support expectant mothers throughout their pregnancy. Consult your gynecologist to understand your baby’s growth and the care that is appropriate for your pregnancy.
