Fetal tissue derived from spontaneous pregnancy losses is insufficient for human transplantation. 
To determine if sufficient fetal tissue with desirable transplant characteristics can be obtained from spontaneous abortions.  A survey of fetal tissues collected from newly diagnosed spontaneous pregnancy losses from three Indianapolis hospitals was conducted from December 1992 to September 1993.  Forty-nine of 356 mothers (13.8%) with spontaneous abortions or ectopic pregnancies consented to the evaluation of their products of conception by gross and microscopic pathologic examination, bacterial culture, cytogenetic analysis, cell culture, and maternal serologic tests.  Forty-nine pregnancies (gestational age range 5-30 weeks) provided four identifiable embryos, 12 second-trimester fetuses, and one third-trimester fetus.  Nine samples (18.4%) were of excellent or good quality on pathologic grading.  Twenty-five of 38 samples tested (66%) grew pathogenic bacteria.  Maternal serologic tests were negative for antibodies to human immunodeficiency virus, human T-cell lymphotropic virus, syphilis, and hepatitis B in all cases.  One of 43 sera was reactive for hepatitis C, and 33 (77%) were positive for cytomegalovirus.  Cytogenetic abnormalities were found in 25% of cultured samples.  Five fetal brain samples had cell viabilities of 50% or more.  Few viable fetal hepatocytes were found.  Only two fetal brain samples (4.1%) were potential candidates for human transplantation.  Spontaneous pregnancy losses yield minimal usable tissue for human transplantation because of a lack of embryonic or fetal tissues, delayed collection, decomposition, genetic abnormality, and bacterial contamination.