RESUMO
On block hysterectomy is defined as the removal of the gravid uterus with its gestational content in situ. The described indications for the realization of this procedure are neoplastic process as the most frequent cause; septic process, persistent trophoblastic diseases, and hemorrhage due to anomalous placentation. This is a retrospective, descriptive study of twelve cases of on block hysterectomy collected from January 1989 to December 1994 at Instituto Nacional de Perinatología. An average age of 33.4 years was found. The number of pregnancies for this patients in average was found to be 4.1. The gestational age was established between 9 to 29 weeks. Four patients with a 4 or more previous miscarriage background. There were two reported cases having a multiple gestation. Among the complications found, there were three cases of hipovolemic shock and one with abcess of vaginal cupula. The average days of hospitalization was 5.3 days. We found no mortality at all in this study, and the histopathologic correlation accorded in 100% of the cases. In this five year review, 12 cases of on block hysterectomy were found, being the most frequent reason for it's realization the persistent trophoblastic diseases; severe hemorrhage in second place, and serious infection process in third. The observed complications were derived from the hemodynamic compromise of each patient. Even though on block hysterectomy is one rarely seen procedure, it most be in mind as an alternative therapeutical instance it most be carried out in third level institutions, with technology and human resources capable of solving any complication derived from this kind of surgery.