Thigh circumference in the detection of intrauterine growth retardation.

Intrauterine growth retardation (IUGR) is associated with an increase in perinatal mortality as well as long-term neurobehavioral morbidity. Despite the increasing sophistication of antenatal fetal assessment, the diagnosis of growth retardation remains difficult. Since the fetal effects of growth inhibition are variable, no one ultrasonic parameter can diagnose with certainty the growth-retarded fetus. The reduction of thigh circumference with IUGR is secondary to the muscle wasting that is characteristic of this disease process. The sensitivity (77.8%) and specificity (75%) of thigh circumference may make it a useful additional sonographic parameter in the evaluation of fetal growth retardation.