Abstract: Objective：To explore the risk factors of ectopic pregnancy after in vitro fertilization and embryo transfer（IVF-ET）. Methods：122 cases of ectopic pregnancy in1 850 cases after IVF-ET treatment
（6.6%）were selected between 2005, Jan. and 2010, Dec. in Center of Reproductive Medicine，Tianjin Central Hospital of Gynecology and Obstetrics，including 11 cases of Heterotopic pregnancy, as the observation group.450 cases were randomly selected from 1 728 cases of intrauterine pregnancy after IVF-ET as control. Pelvicoviduct factors、endometriosis and endometriosis postsurgery factors、ovary diseases、hypomenorrhea, general clinical features were compared between two groups. Results：The ectopic pregnancy rate was significantly increased in those patients with pelvic oviduct factors，endometriosis and endometriosis postsurgery factors， endometrial thickness臆7 mm. Conclusions：For those patients who have above mentioned risk factors，those risk factors should be controlled to the greatest extent when they received IVF-ET treatment. For those patientswho have potential EP, early discovery and diagnosis such as sera hCG level tests and B ultrasounds atreasonable times, and early treatment, are important for them to prevent ectopic pregnancy rupture.

Key words: Fertilization in vitro, Embryo transfer, Pregnancy, ectopic, Risk factors, Pregnancy complications