Causes of limb reduction defects: the contribution of fetal constraint and/or vascular disruption.

Causes for limb defects are often heterogeneous and difficult to discern purely on the basis of their anatomic nature. Because limb defects are common, and because their causes are poorly understood, their occurrence frequently generates concern over the role of prenatal events and exposures. This article serves to guide clinicians as to the proper work-up for such congenital limb anomalies. This evaluation should include a detailed family history, examination of limbs of close relatives, teratogenic history (with full knowledge of which teratogens do and do not cause limb anomalies), evaluation of the uterus, pathologic evaluation of the placenta, and thorough examination of the affected infant for associated defects.