A protocol for the investigation of pregnancy loss. A protocol for the evaluation of pregnancy loss should include a maternal history, dysmorphic examination of the fetus or abortus, photographs, autopsy, chromosome studies (in most cases), and radiographic or xeroradiographic studies. Selected cases with suspected ascending or transplacental infection may require microbiologic investigation. Increasing specialized laboratory techniques may help in the diagnosis of inborn errors of metabolism or storage disorders. Coordination of studies requires the interaction of OB/GYN, pathology, genetics, cytogenetics, and nursing in order to assure delivery of this clinical service. Knowledge of the causes of pregnancy loss and their typical time and mode of presentation can facilitate a focused evaluation, with a high chance of achieving an accurate diagnosis. The goal of all investigations is to provide families with recurrence risk data on which to base future childbearing decisions, as well as information on potential prenatal monitoring. 