Intrauterine Growth Restriction (IUGR)
When an unborn baby is discovered to be below the 10th percentile for his or her gestational age, the condition-which is uncovered by ultrasound examination-is called fetal growth restriction or intrauterine growth restriction (IUGR). This condition is also known as small-for gestational age or SGA. These babies are smaller than they should be for their age.
The Phases Of Fetal Development
A baby's birth weight is not only dependent upon how old s/he is in terms of weeks, but also upon the rate at which the baby has grown in the womb. The process of growth in the womb is very delicate and complex. The baby's growth and development are broken down into three stages. In the first stage, which is considered to be from conception through the beginning of the fourth month, the cells in the baby's organs multiply. The second phase is more of the same-growth and development of cells in the organs. During the third stage or phase, which is after 32 weeks, growth speeds up and the baby can gain weight rapidly, up to 7 ounces per week. If anything is disturbed or interrupted during this process, the baby can be affected by IUGR.
There are two different types of IUGR. Primary, or symmetrical IUGR means that all of the organs are reduced in size. This type of IUGR accounts for about 20 to 25 percent of the cases. Asymmetrical or secondary IUGR means the baby's brain is abnormally larger than the liver, appearing as a large head and small abdomen. It can also mean the baby's head and brain are normal but the lower part of the body is smaller.
Risk Factors For Developing IUGR
There are several conditions and risk factors associated with IUGR including poor nutrition and lifestyle habits that are not healthy, such as smoking, drug use, and/or alcohol abuse. If the mother weighs less than 100 pounds, has gestational diabetes, or pregnancy induced hypertension (PID), the risk is increased. Abnormalities in the baby, such as birth defects or chromosomal abnormalities, placental abnormalities or problems with the umbilical cord can also lead to IUGR. If the pregnancy is a multiple or there are low levels of amniotic fluid in the womb, again, the risk for IUGR is increased.
Diagnosing And Treating IUGR
To diagnose IUGR, it is imperative that the date of the pregnancy is accurate. Early ultrasound or calculation by the first day of the last menstruation are both used to determine the gestational age of the baby. Once that is known, there are markers that indicate IUGR. A discrepancy in the fundal height and the gestational age, measurements made during an ultrasound indicate the baby is smaller than appropriate for gestational age, and abnormal findings through the use of a Doppler ultrasound are all diagnostic methods to determine if the baby is suffering with IUGR.
Treating IUGR continues to be problematic and is dependent upon how far the pregnancy has developed. An early delivery may be suggested if the baby is at 34 weeks or more. If the baby is at less than 34 weeks, the doctor will continue to monitor the baby's well-being as well as the amount of amniotic fluid in the womb. If it appears that either issue is problematic, then delivery will be immediate. An amniocentesis may be suggested during the monitoring to determine the state of the baby's lungs in the event an early delivery is necessary.
Risks To The Baby of Restricted Growth
Risks to the baby include a cesarean delivery, lack of oxygen to the baby at birth, and low blood sugar in the baby. There is also an increased risk that the baby may swallow part of the first bowel movement, called meconium aspiration. This can affect the baby's lungs and cause the baby to develop bacterial pneumonia. There is a risk of an increase in the number of red blood cells, which in turn can cause a decreased flow of blood, called hyperviscosity. Additionally, the baby may be at higher risk for increased motor and neurological disabilities.