This study indicates that SP occur in a higher percentage than theoretically expected after IVF-ET treatment, but it is not conclusive as to whether the SP is independent or a result of the treatment or operative laparoscopy. Our results are in agreement with those of previous studies that have shown that SP occur with almost all kinds of infertility. We therefore reject the previous suggestion of Steptoe, who argued that to prevent ectopic pregnancy from complicating embryo replacement, preparatory electrocauterization of diseased tube should be performed. We also suggest that as long as the results of treatment are below the normal monthly spontaneous conception rate, there is justification for a prospective random study that includes all diagnoses other than BTB. Such a study might help make any future selection of patients for treatment more appropriate.