[Analysis on factors related to spontaneous reduction in twin pregnancy following assisted reproductive technology].

Objective: To explorer factors related to spontaneous reduction in twin pregnancy following assisted reproductive technology. Methods: 2 848 twin pregnant women with treatment of vitro fertilization-embryo transfer (IVF-ET) or intra cytoplasmic sperm injection (ICSI) cycles were enrolled at Assisted Reproductive Centre of the First Affiliated Hospital of Nanjing Medical University, Nanjing Maternity Hospital and Shengjing Hospital of China Medical University from January 2013 to December 2016 respectively. Basic features of subjects, relevant clinical indicators, factors of assisted reproductive therapy and pregnancy outcome were collected from clinical assisted reproductive technology management system. According to the pregnancy outcome, the subjects with spontaneous reduction were classified as case group (n=686), and those with normal twin birth were classified as control group (n=2 162). The features of subjects in the two groups were compared. Non-conditional logistics regression model was used to analyze the related factors of the occurrence of spontaneous reduction. Results: The age of case group and control group were (30.6±4.3) and (30.2±4.0) years old respectively. After the adjustment of male sterile factor, compared to the subjects with luteinizing hormone level on the day of human chorionic gonadotropin administration (HCG) <1.43 IU/L, OR (95%CI) of the subjects with value at 2.59-5.10 IU/L was1.62 (1.08-2.42).Compared to the subjects with number of transferred embryo as 1, OR (95%CI) of the subjects with value as 3 was 0.23 (0.07-0.74). Compared to the subjects with stage of transferred embryo as cleavage stage, OR (95%CI) of the subjects with blastula stage was 0.42 (0.27-0.67). Conclusion: Luteinizing hormone level on day of HCG, number and stage of embryo transfer are related factors to spontaneous reduction in twin pregnancy following assisted reproductive technology.