Fetal Growth Restriction happens when a baby does not grow in the womb as expected. The most common reason is a  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.

In the placenta, the blood of the mother and the baby flows very close togheter. This allows nutrients and oxygen to go to the baby and waste products to go to the mother. If the placenta does not werk 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, also in normal pregnancy.

We often compare your baby’s growth to normal values. This means we look at the baby’s measurements and compare them to those of other babies at the same gestational age of pregnancy. We use percentiles to explain this and is often displayed in the reference growth curve. For example, a baby at the 40th percentile (p40) 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, it is likely normal.

To check if the growth of the baby is too slowly, 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. Another clue is a drop in the percentiles in serial measurements. 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.

A baby is called small if the baby 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 is not always easy and your doctor will look at all these possibilities and decide which one is most likely. When your doctor looks at all the options, there is usually no single tool that gives a clear answer right away. Instead, doctors look at patterns to recognize by checking all signs and symptoms together. Each situation needs a special approach.

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. Signs of FGR are the baby being too small and abnormal blood flow in the baby and the mother. These signs can show low oxygen levels, which can be very dangerous for the baby if birth is not done quickly.

Please remember that every situation is different and has its own approach and outcomes. In general, there are risks related to this serious complication of pregnancy, depending on how severe the signs and symptoms are. Before birth, FGR may lead to stillbirth if the oxygen problem gets worse. If the baby is at an acceptable gestational age and estimated weight, doctors will monitor its condition and attempt to prevent stillbirth by timely delivery. This usually happens through a caesarean section (c-section) if signs of the baby’s health worsening are seen during monitoring. After birth, problems can affect the lungs, bowels, blood, and brain, and sometimes can be life-threatening.

See our FAQ