Fetal growth restriction is the condition when a baby does not grow in the womb as expected. The most common cause is that the placenta that does not give enough nutrients and oxygen to the baby. This can cause serious health problems, especially if it starts early in the pregnancy. FGR is typically diagnosed through careful monitoring during pregnancy, including growth ultrasounds and other tests. It is important to know that most cases of FGR are carefully monitored to ensure the best outcomes for both mother and baby.

The placenta is attached to the womb and the umbilical cord connects the baby to the placenta. In the placenta, the blood of the mother and the baby flows very close together. This allows nutrients and oxygen to go to the baby and waste products to go to the mother. A good exchange of these products is needed for the baby to grow properly during pregnancy. If the placenta does not work well, the baby cannot grow properly and gets low oxygen levels.

Each baby growths in its own way. There is natural variation, especially in the later phases of pregnancy. Around 20 weeks of pregnancy, the average baby weighs about 300 grams, increasing to about 1200 by 28 weeks and about 1900 grams at 32 weeks. In these 4 weeks only, babies grow nearly 60% on average! After 32 weeks, the growth rate slows down.

We often compare your baby’s growth to normal values using percentiles. This means we look at the baby’s measurements and compare them to those of other babies at the same gestational age of pregnancy. This is often displayed in a growth curve (like the example below). For example, if a baby is at the 40th percentile (p40), this means that approximately 40% of babies at that gestational age are smaller, and 60% are larger. If the baby is around the same percentile in later measurements, the growth is likely normal.

A baby is called small if it is within the smallest 10 percent of babies. If a baby is small, it may be just naturally small, or there could be another reason. The placenta might not be working well, or it could be due to a syndrome, a virus, a disease in the mother, smoking, anemia or poor nutrition.

Diagnosing the cause is not always easy. Your doctor will evaluate all possibilities to determine the most likely cause. There is usually not one tool that gives a clear answer right away. Instead, doctors look at patterns to recognize by checking all signs together. Each situation needs a special approach.

There are several methods to assess whether a baby’s growth is progressing as expected. To check the growth of the baby, we compare the baby’s size to normal values, as described in the previous question. The challenge is to find the baby who is not growing well because the placenta is not working properly. This is more likely at the lowest percentiles or if there is a drop in the percentiles in different measurements during the pregnancy. We also look for abnormalities in the blood flow in the baby’s umbilical cord and brain, or in the mother’s blood vessels that supply the womb. Both the baby being too small and abnormal blood flow in the baby and the mother are signs of FGR.

Diagnosing FGR early is very important. If the placenta does not work well, it can cause health problems for the baby and sometimes also for the mother. These signs can show low oxygen levels, which can be very dangerous for the baby if birth is not done quickly.

There is no current treatment or medication available to improve the function of the placenta or the growth of the baby. However, if we know there is an increased risk of low oxygen levels, or if a problem is diagnosed in the baby, a plan can be made to monitor the baby and mother closely during pregnancy. Sometimes this can be done from home with outpatient appointments, or the mother may need to be admitted to the hospital. Ways to monitor include doing ultrasounds to check the blood flow and growth of the baby and regularly performing cardiotocography (CTG). This way, if there is a high risk of low oxygen levels, quick action can be taken, and the baby can be born if it is better for the baby’s health.

Please remember that every situation is different and has its own approach and outcomes. In general, there are risks related to FGR, but the risks are depending on how severe the signs and symptoms are.

Several factors are very important for understanding the risks:

• Gestational age at birth
  • The further along the pregnancy is at birth, the better the chances of avoiding serious complications. This is the most important factor.
• Severity of growth restriction
  • The more the growth is affected, the higher the risk of problems after birth.
• The baby’s condition at birth.
  • If the baby, in addition to being too young and too small, also has a serious oxygen problem around birth, this can lead to serious complications.

Before birth

If the baby is at an acceptable gestational age and estimated weight, doctors will carefully check its condition frequently. One of the risks of FGR is stillbirth, which can occur if the oxygen problem gets worse. That is why it is important to monitor the baby. If there are signs of low oxygen levels or that the baby is not doing well, the doctors will deliver the baby early to prevent stillibrth. This is usually done through a caesarean section (c-section).

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