Fetal Growth Restriction – FGR Overview

Fetal growth restriction, FGR, also known as Intrauterine Growth Restriction is when a baby isn’t growing at a normal weight before birth during pregnancy. To be diagnosed with FGR your baby has to be below the tenth percentile in size of other babies at the same gestational age.

A baby may have fetal growth restriction if the baby is not growing at a rate that is suspected, or isn’t as large as expected for the baby’s gestational age.

Most children who have FGR catch up in height and weight by the age of two. Only in severe cases does it do lasting harm. In severe cases it could affect the growth of organs, tissues, or cells. There are two types of FGR. Symmetrical fetal growth restriction which is where all the parts of the baby measure small.

This type makes up 20 to 25% of all FGR cases. The second type is asymmetrical fetal growth restriction when the head and brain of the child is measuring normal, but the rest of the body is small. This type usually isn’t evident till the third semester.


Fetal growth restriction can cause some complications. These complications can be either before birth or after. FGR can cause premature birth along with low birth weight. A child suffering from fetal growth restriction may not be able to handle the stress of a vaginal delivery.

The baby may have decreased oxygen levels, low blood sugar, low resistance to infection, higher than normal red blood cell count, and trouble controlling temperature. A baby with FGR may also test low on the Apgar test, or be at higher risk of Meconium aspiration. In severe cases FGR can cause stillbirth, or long term growth problems.


There can be lots of causes of fetal growth restriction. Factors can be from both the mother or the baby. You can’t always prevent FGR from happening though living a healthy lifestyle will help lower risks. There may be trouble with the placenta if it isn’t attached well, or there may be limited blood flow from the umbilical cord. Both can cause FGR. Preeclampsia or eclampsia can also cause fetal growth restriction.

Causes of FGR that could be caused by the mother are high blood pressure, anemia, long term lung or kidney problems, autoimmune conditions, very low weight, obesity, poor nutrition, not enough weight gain during pregnancy, alcohol use, drug use, smoking, clotting disorder, thyroid disease, or having an infection like rubella, syphilis. If the baby is a twin or triplet they are both at higher risk for FGR. If the baby suffers from an infection while in the womb, has a birth defect, or gene or chromosome problems.


The first start of diagnosing FGR is finding a very accurate gestational age. Once a gestational age is established then there are different ways your doctor will monitor your baby’s growth. One way is the fundal height. If the fundal height doesn’t coincide with the gestational age could be a sign of fetal growth restriction. To find the fundal height your doctor will measure from the top of the pubic bone to the top of the uterus. Usually the measurement in centimeters will equal the gestational week.

When you are twenty weeks along the fundal height should be around 20cm. Another way to diagnose fetal growth restriction is to do an ultrasound with measurements. Again if the measurements don’t coincide with the gestational age could be a sign of FGR. The last way to check for abnormalities is from a doppler ultrasound. The doppler ultrasound will show the blood flow of the placenta to the umbilical cord. Depending on what is found during these screenings repeated studies may be suggested for the rest of the pregnancy.


There is no one specific treatment of FGR. Treatment plans may differ depending on how severe the fetal growth restriction is. Bed rest may be suggested if blood flow is restricted to the fetus, this will help increase blood flow. Frequent monitoring may also be suggested. This may include extra ultrasounds to measure the baby and see how they are growing. Fetal movement tracking may also be suggested. Other treatments are corticosteroid medicine, or hospital stay. In severe cases your doctor may want to induce labor early or perform a C section delivery.

Fetal growth restriction can be caused by a lot of different things. Either from the mother or the baby causes of what is causing the FGR is important to find out to come up with the best treatment plan. Knowing the most accurate gestational age can be helpful in the fetal growth restriction diagnosis.

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