Pregnancy: Womb growth restriction (Intrauterine Growth Restriction -IUGR)

Sometimes during pregnancy the unborn baby is smaller than it should be because it is not growing at a normal rate inside the womb.   Delayed growth puts the baby at risk for certain health problems during pregnancy, delivery and after birth. These health problems include: low birth weight, decreased oxygen levels, low blood sugar, low Apgar scores, trouble maintaining body temperature, abnormally high red blood cell count, difficulty handling the stress of vaginal delivery, aspiration of stool passed while in the uterus which can lead to breathing problems and low resistance to infection.   Severe cases can lead to stillbirth or may cause long term growth problems.

The main symptom of IUGR is a small for gestational age baby. Specifically, the baby’s estimated weight is below the 10th percentile — or less than that of 90% of babies of the same gestational age.

Depending on the cause of IUGR, the baby may be small all over or look malnourished. They may be thin and pale and have loose, dry skin. The umbilical cord is often thin and dull instead of thick and shiny.

Not all small babies have a problemIf the mother is small, it may be normal for her baby to be small. 

IUGR has many possible causes. A common cause is a problem with the placenta. The placenta is the tissue that joins the mother and fetus, carrying oxygen and nutrients to the baby and permitting the release of waste products from the baby.

The condition can also occur as the result of certain health problems in the mother, such as:

  • Advanced diabetes
  • Lupus
  • Infections
  • Kidney disease or lung disease
  • Malnutrition or anemia (low red blood cells)
  • Clotting disorders
  • High blood pressure or heart disease
  • Smoking, drinking alcohol, or abusing drugs
  • Other possible causes include chromosomal defects in the baby or multiple gestation (twins, triplets, or more).
  • Additionally, an unborn baby may not get enough oxygen and nutrition from the placenta during pregnancy because of: high altitudes or preeclampsia or eclampsia.

Your obstetrician has many ways to estimate the size of babies during pregnancy. One of the simplest and most common is measuring the distance from the mother’s fundus (the top of the uterus) to the pubic bone. After the 20th week of pregnancy, the measure in centimeters usually corresponds with the number of weeks of pregnancy. A lower than expected measurement may indicate the baby is not growing as it should. There are also other ways to assess your baby’s health which include:

Ultrasound. The main test for checking a baby’s growth in the uterus, ultrasound involves using sound waves to create pictures of the baby. The ultrasound exam lets the doctor see the baby in the uterus with an instrument that is moved over the mother’s abdomen.

An ultrasound can be used to measure the baby’s head and abdomen.  Your obstetrician or health care provider can compare the measurements to growth charts to estimate the baby’s weight. Ultrasound can also be used to determine how much amniotic fluid (liquid that surrounds your baby in the womb) is in the uterus. A low amount of amniotic fluid could indicate a problem.

Doppler flow. Doppler flow is a technique that uses sound waves to measure the amount and speed of blood flow through the blood vessels. This test is used to check the flow of blood in the umbilical cord and vessels in the baby’s brain.

Weight checks. Your obstetrician will routinely check and record your weight at every prenatal checkup. Weight gain can be used to measure the growth of your unborn baby.

Fetal monitoring. This test involves placing sensitive electrodes on the mother’s abdomen. The electrodes are held in place by a lightweight stretchable band and attached to a monitor. The sensors measure the rate and pattern of the baby’s heartbeat.

Amniocentesis. In this procedure, a needle is placed through the skin of the mother’s abdomen and into her uterus to withdraw a small amount of amniotic fluid for testing. Tests may detect infection or some chromosomal abnormalities.

The best way to manage Intrauterine growth restriction depends on the severity of growth restriction and how early the problem started in the pregnancy. Generally, the earlier growth restriction begins and the more severe it is, the greater the risk to the unborn baby. Careful monitoring of  the unborn baby, using tests such as ultrasound, Doppler flow, and fetal monitoring, may be helpful.

Although it is not possible to reverse intrauterine growth restriction, there are ways to help slow or minimize the effects.

  • Improve nutrition: Some studies have shown that increasing the mother’s nutrition may increase the baby’s weight gain and growth in the uterus.
  • Bed Rest: Bed rest may help improve circulation to your baby.
  • Early delivery or cesarean section( C section): If  the condition puts your baby’s health in danger, the doctor may decide to deliver the baby early. If the doctor believes the baby is too weak for the stresses of labor and delivery, or if the baby has problems during labor, a cesarean section (C section) may be safer.

This condition can occur even when a mother is perfectly healthy.  There are things you can do to reduce risks and increase the odds of a healthy pregnancy and baby.

  • Keep all of your prenatal appointments. Detecting potential problems early allows you treat them early.
  • Be aware of your baby’s movements. A baby who doesn’t move often or who stops moving may have a problem. If you notice changes in your baby’s movement, call your doctor.
  • Discuss your medications with your obstetrician.  Sometimes a medication a mother is taking for another health problem can lead to problems with her unborn baby.
  • Eat healthfully.  Healthy foods and ample calories help keep your baby well nourished. If you are unable to get healthy foods needed, please discuss with your obstetrician as there may be local resources available to help supplement your diet (WIC or other community resources).
  • Get plenty of rest. Rest will help you feel better and it may even help your baby grow. Try to get eight hours of sleep(or more) each night.  Naps for hour or two in the afternoon is also good for you.
  • Practice healthy lifestyle habits. If you drink alcohol, take drugs, or smoke, stop for the health of your baby.


MedlinePlus: Intrauterine Growth Restriction


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