Selective Fetal Growth Restriction (sFGR) is also known as Selective Intrauterine Growth Restriction (sIUGR). This condition can happen in identical twins who share one placenta. Sometimes, the placenta is not shared evenly. When this happens, one baby may get less blood flow, oxygen and nutrition than the other baby. When one baby gets a smaller share of the placenta, that baby may grow more slowly and may have a higher chance of health problems. In more serious cases, blood flow through the umbilical cord may not be normal. This can affect the smaller baby and may also put the larger twin at risk.
Careful monitoring, and sometimes treatment before birth, can help your care team choose the safest plan for you and your babies.
Overview
Overview
The Smaller Twin
With sFGR, one twin gets a smaller part of the shared placenta. This means the baby may not get enough nutrients and oxygen to grow as expected. This baby may be much smaller than the other twin. Ultrasound tests may also show changes in blood flow. In severe cases, the smaller twin can become very sick before birth.
The Larger Twin
Even if the larger twin seems to be growing well, that baby can still be affected. This is because the twins share blood vessel connections in the placenta. If the smaller twin becomes very sick or dies before birth, the larger twin may have serious problems, such as blood loss, anemia, brain injury or death.
Risk Factors for sFGR
Risk Factors for sFGR
sFGR only happens in twin pregnancies where the babies share one placenta. It affects about 10% to 15% of monochorionic twin pregnancies. Monochorionic means the twins share one placenta. The biggest risk factor is being pregnant with this type of twin pregnancy.
How is Selective Fetal Growth Restriction Diagnosed?
How is Selective Fetal Growth Restriction Diagnosed?
A maternal-fetal medicine specialist can diagnose sFGR with a detailed ultrasound. First, the care team confirms that the twins share one placenta. Then, they measure each baby’s growth and compare the babies’ sizes. sFGR is often diagnosed when one baby is smaller than expected for how far along the pregnancy is.
The care team may also use Doppler ultrasound to check blood flow in the umbilical cord and other blood vessels. They will also check the amount of amniotic fluid around each baby and continue to watch the babies’ growth closely. It is also important to check for twin-to-twin transfusion syndrome (TTTS) and other problems that can happen when twins share one placenta. These conditions can look similar and may affect the treatment plan.
How is Selective Fetal Growth Restriction Treated?
How is Selective Fetal Growth Restriction Treated?
Treatment depends on how serious the growth restriction is, how blood is flowing through the umbilical cord, how far along the pregnancy is and whether there are other concerns, such as TTTS. In many cases, treatment includes close monitoring with regular ultrasounds, Doppler tests and other checks. These visits help the care team decide the safest time for delivery.
For more serious cases, the fetal therapy team may talk with you about treatment options before birth. The Fetal Center at Riley Children’s Health offers selective fetoscopic laser photocoagulation for some complicated twin pregnancies where the babies share one placenta, including some cases of sFGR. Your care team will review your pregnancy closely and recommend the plan that is safest for you and your babies.
Locations
Locations
Locations
In addition to our primary hospital location at the Academic Health Center in Indianapolis, IN, we have convenient locations to better serve our communities throughout the state.