title: [Comparison of clinical outcomes of vitrified-thawed embryo transfer and fresh embryos transfer].
abstract: OBJECTIVE
  To understand the clinical outcomes of frozen embryo transfer and fresh embryo transfer.
  
  
  METHODS
  A retrospective analysis was conducted on the clinical data of 870 cases receiving embryo transfer at the Reproductive Medical Center of Sun Yat-Sen Memorial Hospital from January 2013 to March 2014, including 577 cases of in vitro fertilization and fresh embryo transfer, 118 cases of intracytoplasmic sperm injection and fresh embryo transfer and 175 cases of frozen thawed embryo transfer, to compare the clinical characteristics and outcomes between fresh embryo transfer group and frozen embryo transfer group (the patients who had received unsuccessful fresh embryo transfer). The frozen embryo transfer group was divided into pregnant subgroup and non pregnant subgroup to further comparison. Binary logistic regression analyses was performed to identify the influencing factors of pregnancy.
  
  
  RESULTS
  The implantation rate and clinical pregnancy rate were significantly lower in frozen embryo transfer group than in fresh embryo transfer group (26.27% vs. 31.98%, P = 0.01 and 47.43% vs. 65.18%, P < 0.001). The differences in abortion rate, biochemical pregnancy rate and fetal birth weight had no statistical significance between the two groups (P = 0.63, P = 0.17 and P = 0.33). The difference in age between pregnant subgroup and non pregnant subgroup was statistical significant (30.69 ± 3.37 years vs. 32.00 ± 5.09 years, P = 0.03), but no significant differences were found in BMI, duration of infertility and basic endocrine between the two subgroups. Binary logistic regression analysis showed that receiving frozen embryo transfer or not (P < 0.001), wife's age (P < 0.001), BMI (P = 0.011) and number of top quality embryos (P < 0.001) were influencing factors of pregnancy.
  
  
  CONCLUSIONS
  Lower implantation rate and clinical pregnancy rate was observed in the patients in frozen embryo transfer group, who had received unsuccessful fresh embryo transfer, but no increase of abortion rate, influence on fetal birth weight and adverse pregnancy outcome were observed.
authors.affiliation: Center for Reproductive Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Center for Reproductive Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Ruiqi
authors.initials: R
authors.lastname: Li
authors.affiliation: Center for Reproductive Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Nengyong
authors.initials: N
authors.lastname: Ouyang
authors.affiliation: Center for Reproductive Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Lingyan
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Center for Reproductive Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China.
authors.forename: Songbang
authors.initials: S
authors.lastname: Ou
authors.affiliation: Center for Reproductive Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China. Email: wenjungzcn@163.com.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wang
mesh_terms: D001724:Birth Weight; D015925:Cryopreservation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic