Definition of Intrauterine growth restriction:

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.