Fetal Growth Restriction; Intrauterine Growth Restriction (IUGR); Small for Gestational Age

Are there different types of Fetal Growth Restriction?

There are basically two different types of fetal growth restriction:

Symmetric or primary growth restriction is characterized by all internal organs being reduced in size. Symmetric growth restriction accounts for 20% to 25% of all cases of growth restriction.

Asymmetric or secondary growth restriction is characterized by the head and brain being normal in size, but the abdomen is smaller. Typically this is not evident until the third trimester.

What are the risk factors for developing Fetal Growth Restriction?

Pregnancies that have any of the following conditions may be at a greater risk for developing fetal growth restriction:

• Maternal weight of less than 100 pounds
• Poor nutrition during pregnancy
• Birth defects or chromosomal abnormalities
• Use of drugs, cigarettes, and/or alcohol
• Pregnancy induced hypertension (PIH)
• Placental abnormalities
• Umbilical cord abnormalities
• Multiple pregnancy
• Gestational diabetes in the mother
• Low levels of amniotic fluid or oligohydramnios
  

How is Fetal Growth Restriction diagnosed?

One of the most important things when diagnosing fetal growth restriction is to ensure accurate dating of the pregnancy. Gestational age can be calculated by using the first day of your last menstrual period (LMP) and also by early ultrasound calculations.

Once gestational age has been established, the following methods can be used to diagnose fetal growth restriction:

• Fundal height that does not coincide with gestational age
  
• Measurements calculated in an ultrasound are smaller than would be expected for the gestational age
• Abnormal findings discovered by a Doppler ultrasound
  

How is Fetal Growth Restriction treated?

Despite new research, the optimal treatment for fetal growth restriction remains problematic. Most likely the treatment will depend on how far along you are in your pregnancy.

• If gestational age is 34 weeks or greater, health care providers may recommend being induced for an early delivery.
  
• If gestational age is less than 34 weeks, health care providers will continue monitoring until 34 weeks or beyond. Fetal well-being and the amount of amniotic fluid will be monitored during this time. If either of these becomes a concern, then immediate delivery may be recommended.

Depending on your health care provider, you will likely have appointments every 2 to 6 weeks until you deliver. If delivery is suggested prior to 34 weeks, your health care provider may perform an amniocentesis to help evaluate fetal lung maturity.