[Clinical analysis of 12,491 cycles treated in embryo transfer program].

Objective: To analyze the clinical outcomes of patients treated with in vitro fertilization and embryo transfer (IVF-ET) and influence factors of pregnancy rate.
Methods: We retrospectively analyzed the clinical data of 12,491 cycles, including 6,832 fresh IVF/intracytoplast single sperm injection (ICSI) cycles and 5,659 frozen embryo transfer (FET) cycles from 2005 to 2007.
Results: The clinical pregnancy rate per cycle was 32.99% (2254/6832) in fresh embryo transfer program, and the live birth rate was 25.75% (1394/5413); the early pregnant loss rate was 9.36% (211/2254), and the prenatal defect rate was 1.45% (25/1722). Through analysis of these patients' basic data, we found that the patients' age, causes for infertility, egg retrieval and cycle number affected the pregnancy rate. Using logistic regression method, we found that patients' age was the most important factor affecting pregnancy outcome. In FET cycles, the clinical pregnancy rate was 38.08% (2155/5659), significantly higher than fresh embryo transfer cycles.
Conclusions: IVF-ET treatment is a safe and effective method for infertility couples. However, the female age and poor ovarian response are the main factors affecting pregnancy rate. Thawed embryo transfer can increase the accumulated pregnancy rate effectively.