Received March 25, 2002
Accepted April 11, 2002

Natural heterotopic pregnancy (HP) is a rare phenomenon resulting from simultaneous intrauterine and extrauterine multiple embryo implantations. The incidence of heterotopic pregnancy (HP) seems to be increased in infertile women underwent "in vitro" fertilization and embryo transfer (IVFET). ln most of HP cases reported in literature, the concurrent ectopic sites were at locations of fallopian tubes. Other concomitant locations of the heterotopic implantation were also reported including cornual, ovarian, abdominal and cervical implantations. The predisposing factors that are involved in the pathogenesis ofHP are similar to the risk factors for primary ectopic pregnancies (EP) including presence of pelvic pathology and more than four embryos transferred in IVF-ET programs. Laparoscopy remains the gold standard approach for the diagnosis which is also therapeutic in some cases. There are no laboratory approaches to predict this kind of ectopic pregnancy so far. With new ultrasonographic imaging technologies, especially transvaginal sonography and color doppler ultrasound, early HP diagnosis has been done, in the last years. These new technologies enable advanced and new treatment modalities in addition to surgery. The treatment of HP is usually carried out by salpingectomy. However, alternative non-surgical and laparoscopic approaches with organ preservation have been successfully used in the last years. Therefore, more experience is needed for application of new treatment modalities and with new approaches in the IVF-ET, early diagnosis and skillful treatment, the outcome of the concurrent intra-uterine pregnancies will be better in future.