Intrauterine growth restriction refers to the poor growth of a baby while in the womb. Specifically, it refers to a fetus whose weight is below the 10th percentile for its gestational age.

Causes, incidence, and risk factors
Many different things can lead to intrauterine growth restriction (IUGR). An unborn baby may not get enough nutrition because of:

• Heart disease in the mother
• High altitudes
• Multiple pregnancies (twins, triplets, etc.)
• Placenta problems
• Preeclampsia or eclampsia

Congenital or chromosomal abnormalities are often associated with below-normal weight. Infections during pregnancy that affect the fetus, such as rubella, cytomegalovirus, toxoplasmosis, and syphilis may also affect the weight of the developing baby.

Risk factors in the mother that may contribute to IUGR include:

• Alcohol abuse
• Drug addiction
• High blood pressure or heart disease
• Poor nutrition
• Smoking

If the mother is small, it may be normal for her to have a small fetus, but this is not due to IUGR.

Depending on the cause of IUGR, the fetus may be symmetrically small, or have a head that is normal size for gestational age, while the remainder of the fetus is growth restricted.

Symptoms

• Currently pregnant with a feeling that the baby is not as big as it should be
• Uterine fundal height less than expected for gestational age

Signs and tests
Intrauterine growth restriction (IUGR) may be suspected if the size of the pregnant woman's uterus is small. The condition is usually confirmed by ultrasound.

Further tests may be needed to screen for infection or genetic problems if IUGR is suspected.

Treatment
IUGR increases the risk for intrauterine death. If this condition is suspected, the pregnant woman will be closely monitored with several pregnancy ultrasounds to measure the baby's growth, movements, blood flow, and fluid around the baby. Non-stress testing will also be done. Depending on the results of these tests, delivery may be necessary.

Expectations (prognosis)
The prognosis for normal newborn growth and development varies by the degree and cause of IUGR. Prognosis should be discussed with your obstetrician and pediatrician.

Complications
Depending on the specific cause, IUGR increases the risk for a variety of pregnancy and newborn complications. Infants may have a non-reassuring fetal heart rate during labor, requiring delivery by c-section.

Calling your health care provider
Contact your provider right away if you are pregnant and notice that the baby is moving less than usual.

Also call your health care provider if your infant or child does not seem to be growing or developing normally.

Prevention
Control risk factors during pregnancy, when possible. Avoid alcohol, smoking, and drug use, and get regular prenatal care.

References
Baschat AA, Galan HL, Ross MG, Gabbe SG. Intrauterine growth restriction. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2007:chap 29.

Williams DE, Pridjian G. Obstetrics. In: Rakel RE, ed. Textbook of Family Medicine. 7th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 29.

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