Intrauterine growth restriction (IUGR) refers to the poor growth of a baby while in the mother's womb during pregnancy. Specifically, it means the developing baby weights less than 90% of other babies at the same gestational age.
Intrauterine growth retardation; IUGR
Causes, incidence, and risk factors
Many different things can lead to intrauterine growth restriction (IUGR). An unborn baby may not get enough oxygen and nutrition from the placenta during pregnancy because of:
Multiple pregnancy (twins, triplets, etc.)
Preeclampsia or eclampsia
Congenital or chromosomal abnormalities are often associated with below-normal weight. Infections during pregnancy that affect the developing baby, 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:
High blood pressure or heart disease
If the mother is small, it may be normal for her the baby to be small, but this is not due to IUGR.
Depending on the cause of IUGR, the developing baby may be symmetrically small, or have a head that is normal size for gestational age, while the remainder of it's body is small.
A pregnant woman may feel that her baby is as big as it should be. The measurement from the mother's pubic bone to the top of the uterus will be smaller than expected for the baby's gestational age. This measurement is called the uterine fundal height.
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.
IUGR increases the risk that the baby will die inside the womb before birth. If your doctor thinks you might have IUGR, you 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.
After delivery, growth and development of the newborn depends on the severity and cause of IUGR. The baby's outlook should be discussed with your obstetrician and pediatrician.
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.
Avoid alcohol, smoking, and drug use, eat a healthy diet, and get regular prenatal care. If you have a chronic medical condition or take prescribed medications regularly, see your doctor before you get pregnant. This can help reduce any effects of your medical condition on your pregnancy and the baby.
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.
Linda Vorvick, MD, Family Physician, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.