Fetal Growth Restriction
What is fetal growth restriction (FGR)?
Fetal growth restriction (FGR) is a condition in which an unborn baby (fetus) is smaller
than expected for the number of weeks of pregnancy (gestational age). It's often described
as an estimated weight less than the 10th percentile. This means that the baby weighs
less than 9 out of 10 babies of the same gestational age. Newborn babies with FGR
may be called “small for gestational age.”
FGR can begin at any time during pregnancy. With FGR, the baby doesn't grow well.
FGR may affect the overall size of the baby and the growth of organs, tissues, and
cells. This can cause many problems. But many newborns who are small may just be small.
They may not have any problems.
What causes FGR?
Many things increase the risk for FGR. These include problems with the placenta or
umbilical cord. The placenta may not attach well. Or the blood flow through the umbilical
cord may be limited. Factors in both the mother and the baby may cause FGR.
Factors in the mother that can cause FGR include:
High blood pressure or other heart and blood vessel disease
Too few red blood cells (anemia)
Long-term lung or kidney conditions
Autoimmune conditions such as lupus
Very low weight
A large amount of excess weight (obese)
Poor nutrition or weight gain
Alcohol or drug use
Factors in the baby that can cause FGR include:
Being one of a twin or triplets
Birth defects, such as heart defects
Problem with genes or chromosomes
What are the symptoms of FGR?
A pregnant woman doesn’t have symptoms of FGR. But a baby with FGR may have certain
signs after birth, such as:
How is FGR diagnosed?
One of the main reasons for regular prenatal exams is to make sure your baby is growing
well. During pregnancy, the size of your baby is estimated in different ways, including:
Fundal height. To check fundal height, your healthcare provider measures from the top of your pubic
bone to the top of your uterus (fundus). Fundal height, measured in centimeters (cm),
is about the same as the number of weeks of pregnancy after the 20th week. For example,
at 24 weeks gestation, your fundal height should be close to 24 cm. If the fundal
height is less than expected, it may mean FGR.
If your healthcare provider thinks you have FGR, you'll have other tests. These include:
Fetal ultrasound. Estimating fetal weight with ultrasound is the best way to find FGR. Ultrasound uses
sound waves to create images of the baby in the uterus. Sound waves won't harm you
or the baby. Your healthcare provider or a technician will use the images to measure
the baby. A diagnosis of FGR is based on the difference between actual and expected
measurements at a certain gestational age.
Doppler ultrasound. You may also have this special type of ultrasound to diagnose FGR. Doppler ultrasound
checks the blood flow to the placenta and through the umbilical cord to the baby.
Decreased blood flow may mean your baby has FGR.
You may have repeat ultrasound exams, Doppler studies, and other tests.
How is FGR managed?
Management depends on how serious the FGR is. This is based on the ultrasound (estimated
fetal weight) and Doppler ultrasound (blood flow to the baby), as well as risk factors
and the number of weeks gestation.
Treatment may include:
Frequent monitoring. This means you will have prenatal visits more often, and ultrasound and Doppler ultrasound
exams. You may have other tests.
Tracking fetal movements. Your healthcare provider may also ask you to keep track of fetal movements. If so,
they will give you instructions.
Early delivery or emergency cesarean section
What are possible complications of FGR?
FGR can cause many serious complications. Your baby may need to be delivered early
and stay in the hospital. Your baby may have trouble breathing, infections, and other
problems. Stillbirths and death may occur. As your child grows, they'll be at higher
risk for heart and blood vessel problems.
How can FGR be prevented?
FGR can happen in any pregnancy. But some factors, like cigarette smoking or alcohol
or medicine use, increase the risk for FGR. Regular and early prenatal care and a
healthy diet and steady weight gain help to prevent FGR and other problems.
When should I call my healthcare provider?
Make sure your healthcare provider knows your health history. If you're counting fetal
movements and find that the number has decreased, let your healthcare provider know.
And if you notice other changes or if you have concerns about your pregnancy, call
your healthcare provider.
Key points about fetal growth restriction
FGR is a condition in which the baby is smaller than expected for gestational age.
Many factors increase the risk for FGR. They may be related to the placenta, mother,
Estimating fetal weight with ultrasound is the best way to identify FGR.
If FGR is diagnosed, you will need to be closely monitored.
Tips to help you get the most from a visit to your healthcare provider:
Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells
At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed, and how it will help you. Also
know what the side effects are.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that
Know how you can contact your provider if you have questions.