Infections in the fetus, such as cytomegalovirus, rubella or other infections, may also restrict fetal growth. However, not every authority accepts maternal anemia as a cause of intrauterine-growth retardation. Abnormalities of the umbilical cord or placenta may cause inhibited growth because the baby has received less nutrition during pregnancy. A woman who has delivered a growth-retarded infant may be more likely to do so again in subsequent pregnancies. Other reasons for a small baby, unrelated to IUGR, include the fact that that a woman who is small might have a small baby.
Prolonged pregnancy can lead to an undernourished, smaller baby.
A malformed or abnormal fetus may also be smaller, especially when chromosomal abnormalities are present. Diagnosing IUGR can be difficult. One reason your doctor measures you at each visit is to see how your uterus is growing. A problem is usually found by measuring the uterus over a period of time and finding no change. Diagnosis of this type of problem is one important reason to keep all your prenatal appointments.