Intrauterine growth restriction (IUGR) may be suspected if the size of the mother's uterus is small. The condition is usually confirmed by ultrasound. Several factors can cause poor growth of a fetus. Undernutrition of the fetus may occur as a result of insufficiency of the placenta, multiple pregnancies, heart disease in the mother, preeclampsia or eclampsia, and high altitude. Fetuses with 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 fetal weight. Risk factors in the mother that may contribute to intrauterine growth retardation include poor nutrition, heart disease or high blood pressure, smoking, drug addiction, and alcohol abuse. 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.
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