Abstract: Objective：To investigate the rate and correlation risk factors of early pregnancy loss in IVF/ICSI-ET. Methods：Calculated the IVF/ICSI-ET patients between May 2001 to December 2007，five hundred forty-seven cases with pregnancy were enrolled in this study, then divided into pregnancy loss group and ongoing pregnancy group. Their age，weight，pregnancy history，ARTs program，endocrine hormone on Day 3，ignition day，hCG administration day，oocyte retrieval day，and ET day were compared. The etiology of infertility，evaluation of sperm，echo patten and thickness of endometrium on hCG administration day， number of retrieved oocytes and embryo for cryopreservation， score of ET embryo，Serum β-hCG level，number of gestational sac on sonography were analyzed，risk factors were evaluated statistically. Results：The rate of early pregnancy loss in IVF/ICSI-ET is 26.87%，the clinical abortion rate is 16.45%. Anovulation of PCOS，the female age，the number of gestational sac on sonography，have significant difference between pregnancy loss group and ongoing group. Conclusions：The rate of early pregnancy loss in IVF/ICSI-ET is similar with the spontaneous abortion of natural pregnancy. The risk factors of early pregnancy loss in IVF/ICSI-ET may be related with the anovulation of PCOS，women′s age，the number of gestational sac in uterus 4-6 weeks following embryo transfer.

Key words: Fertilization in vitro, Embryo transfer, Risk factors, Pregnancy outcome, Early pregnancy loss