This leaflet is to help you understand what fetal growth restriction is and what causes it, the implications of being diagnosed, and what treatment options are available.

What does the term “small for gestational age” (SGA) mean?

A fetus is considered to be SGA when its size (biometric evaluation by ultrasound) is below a predefined threshold for its gestational age, usually estimated fetal weight or abdominal circumference below the 10th percentile of given reference ranges.

What is the significance of an estimated fetal weight that is at the 10th percentile?

If your fetus´ weight is estimated to be at the 10th percentile, it means that 10 percent of unborn children at the same gestational age are smaller than your child and 90% weigh more.

What is fetal growth restriction (FGR)?

Fetal growth restriction (FGR) refers to a condition in which a fetus is unable to achieve its genetically determined potential size. They almost always are small for gestational age.

What is the difference between SGA and FGR?

The main difference between SGA and FGR is that an SGA fetus may be small but not at increased risk of adverse perinatal outcome.

What causes FGR?

There many causes of FGR that can be fetal (infections, congenital anomalies) or placental (placental insufficiency).  Maternal conditions such as hypertension and preeclampsia (pregnancy associated hypertension) are also frequently associated with placental insufficiency and FGR.

How is the diagnosis of FGR made?

When a fetus is suspected to be SGA by determining the estimated fetal weight, obstetric Doppler, a technique which evaluates blood flow through the placenta and to the baby, is used to diagnose placental insufficiency.

Are fetal growth restrictions high risk?

Babies with FGR are at greater-than-normal risk for a variety of health problems before, during and after their birth. These problems include low oxygen levels while in the womb, a high level of distress during labor and delivery, and an increased risk of infectious disease after birth.

Should I be worried about fetal growth restriction?

Severe 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, especially if born prematurely. Stillbirths and death may occur.

How is FGR managed?

Management depends on how serious the FGR is. This is based on the ultrasound (which determines the estimated fetal weight) and Doppler ultrasound (evaluates the blood flow to the baby), as well as the gestational age.

What is the treatment of FGR?

Treatment of FGR is based on close monitoring of fetal well-being to choose the best time to deliver the fetus if it is suspected to be at high risk of demise or compromise.

Last updated May 2023