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 is 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 does not 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.

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
  • Diabetes
  • 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
  • Cigarette smoking

Factors in the baby that can cause FGR include:

  • Being one of a twin or triplets
  • Infections
  • Birth defects, such as heart defects
  • Problem with genes or chromosomes

A
pregnant woman doesn’t have symptoms of FGR. But a baby with FGR may have certain signs
after birth, such as:

  • Low birth weight
  • Low blood sugar levels
  • Lower body temperature
  • High level of red blood cells
  • Trouble fighting infections

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 will 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 womb. Sound waves will not 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.

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 is
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, he or she will give you instructions.
  • Corticosteroid medicine
  • Hospital stay
  • Early delivery or emergency cesarean

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, he or she will be at higher risk for heart and blood vessel problems.

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.

Make sure your healthcare provider knows your health history. If you are 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.

  • 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, or baby.
  • 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 you.
  • 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 visit.
  • Know how you can contact your provider if you have questions.