ABSTRACT
Small-for-gestational-age (SGA) fetuses are a heterogeneous group that can be broadly classified into: constitutionally small because of familial or racial factors (the majority of SGA fetuses can be regarded as “normal small” babies that are not at increased risk of intrauterine death or perinatal asphyxia) and growth retarded, due to uteroplacental insufficiency, genetic disease, intrauterine infection, or toxic damage. The finding of an SGA fetus, especially when severely affected and of early onset, in the second trimester, raises the possibility of the fetus being chromosomally abnormal. The advantage over amniocentesis is that chromosomal analysis can be performed directly without the need for prolonged culture and therefore the diagnosis of aneuploidy can be made within 24 h of sampling. The use of cordocentesis in cases of intrauterine growth retardation enables the identification of those fetuses that are hypoxic and has allowed validation of Doppler blood flow measurement as a noninvasive means of monitoring the condition of SGA fetuses.
