Intrauterine growth restriction (IUGR)
The most common
definition of intrauterine growth restriction (IUGR) is fetal weight below the
10th percentile for gestational age, as determined by ultrasound. IUGR is also
known as fetal growth restriction (FGR) or small for gestational age.
Are there different types of IUGR?
There are basically
two different types of IUGR:
- Symmetrical or primary IUGR is characterized by a decrease in the size of all internal organs. Symmetrical IUGR accounts for 20-25% of all cases of IUGR.
- Asymmetric or secondary IUGR is characterized by normal head and brain size, but a smaller abdomen.
- It usually doesn't show up until the third trimester.
What are the risk factors?
Pregnancies with any
of the following conditions may be at a higher risk of developing IUGR:
- Maternal weight less than 45 kilograms
- Poor nutrition during pregnancy
- Birth defects or chromosomal abnormalities
- Use of drugs, cigarettes, and/or alcohol
- Pregnancy-induced hypertension
- Placental abnormalities
- Umbilical cord abnormalities
- Multiple pregnancies
- Gestational diabetes in the mother
- Low levels of amniotic fluid or oligohydramnios
How is IUGR diagnosed?
One of the most
important points in the diagnosis of IUGR is the exact determination of the
gestational age. Gestational age can be calculated from the first day of the
last menstrual period as well as early ultrasound calculations.
After determining the
gestational age, the following methods can be used to diagnose IUGR:
- A fundal height that does not coincide with gestational age
- Measurements calculated in ultrasound are smaller than would be expected for the gestational age
- Abnormal findings discovered by a Doppler ultrasound
How is it treated?
Despite new research,
optimal treatment for IUGR remains problematic. Treatment will most likely
depend on how far along you are in your pregnancy.
If your pregnancy is
34 weeks or more, doctors may recommend early labor induction.
If the pregnancy is
less than 34 weeks, doctors will continue monitoring until 34 weeks or longer.
At this time, the well-being of the fetus and the amount of amniotic fluid will
be monitored. If any of these issues become a problem, immediate delivery may
be recommended. Depending on your doctor, you will probably come in for an
appointment every 2-6 weeks until delivery. If delivery is expected before 34
weeks, the doctor may perform an amniocentesis to assess the degree of maturity
of the fetus's lungs.
What are the risks for a baby born with IUGR?
- Increased risk for cesarean delivery
- Increased risk for hypoxia (lack of oxygen when the baby is born)
- Increased risk for meconium aspiration, which is when the baby swallows part of the first bowel movement. This can cause the alveoli to be over distended, a pneumothorax to occur, or the baby can develop bacterial pneumonia.
- Hypoglycemia (low blood sugar)
- Polycythemia (increased number of red blood cells)
- Hyperviscosity (decreased blood flow due to an increased number of red blood cells)
- Increased risk for motor and neurological disabilities