Relationship between Pregnancy Outcome and Maternal Age and Number of Transferred Embryos in Infertile Patients Undergoing FET

Objective: To investigate the influence of maternal age and the number of transferred embryos on pregnancy outcomes in infertile patients undergoing frozen thawed embryo transfer (FET). Methods: A retrospective analysis was performed in our center on the clinical data of 1 052 thawing cases from January 2004 to December 2008. There were 6 groups in the study including A group (≤34 year-old), B group (35-39 year-old), C group (≥40 year-old), D group(single embryo transfer),E group (2-embryo transfer ) and F group(3-embryo transfer). Results: The implantation rate was significantly lower in A group compared with that of B group (P 0.05), but higher than that of C group (P 0.05). The abortion rate was significantly lower in A group compared with that of B group (P 0.05).There were significant differences in multiple pregnancy rate and fetal reduction rate between E group and F group (P 0.05). There was no difference in ectopic pregnancy rate between groups (P 0.05). Conclusion: The implantation rate decreased significantly in patients≥40 year-old. The number of transferred embryos was not correlated with ectopic pregnancy and abortion rate. Transplantation of 2 call embryos is the reasonable choice.