title: [Study on the incidence and influences on ectopic pregnancy from embryo transfer of fresh cycles and frozen-thawed cycles].
abstract: OBJECTIVE
  To investigate ectopic pregnancy from embryo transfer (ET)of in-vitro fertilization (IVF) cycle and intracytoplasmic sperm injection (ICSI) cycle and frozen-thawed (FET) cycle.
  
  
  METHODS
  From Jan.2005 to Dec. 2010, a total of 9037 IVF-ET or ICSI-ET cycles and 4034 FET cycles were performed in our reproductive medicine center, Affiliated First Hospital of Zhengzhou University. The incidence of ectopic pregnancy rate was studied in fresh cycles IVF-ET (5998) and ICSI-ET (3039) cycles, and natural FET (2198) and hormone replacement (E-P) FET (1836) cycles.
  
  
  RESULTS
  Of 4034 FET cycles, 1090 clinical pregnancies and 26 ectopic pregnancies were observed, the incidence of ectopic pregnancy was 2.38% (26/1090). Of 9037 fresh cycles, 3602 cycles were clinical pregnancy, and 133 cycles were ectopic pregnancy, and the incidence of ectopic pregnancy was 3.69% (133/3602). The ectopic pregnancy rate in FET cycles was lower than in fresh cycles significantly (P < 0.05). Of 3039 fresh ICSI-ET cycles, the incidence of ectopic pregnancy was 2.62% (34/1298) in 1298 clinical pregnancies. Of 5998 IVF-ET cycles, 2304 clinical pregnancies were observed, the incidence of ectopic pregnancy was 4.30% (99/2304). Ectopic pregnancy rate in the fresh ICSI-ET cycles was lower than that of IVF-ET group significantly (P < 0.01). The ectopic pregnancy rate in the natural FET cycles was 1.46% (8/547), which was significantly lower than 3.31% (18/543) in E-P group (P < 0.05).
  
  
  CONCLUSIONS
  The incidence of ectopic pregnancy of FET cycles was significantly lower than that of fresh embryo transfer cycles. The application of exogenous sex hormones in assisted reproductive cycles might increase occurrence of ectopic pregnancy.
authors.affiliation: Reproductive Medical Center, Affiliated First Hospital of Zhengzhou University, China.
authors.forename: Yi-le
authors.initials: YL
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Ying-chun
authors.initials: YC
authors.lastname: Su
authors.forename: Yi-hong
authors.initials: YH
authors.lastname: Guo
authors.forename: Ying-pu
authors.initials: YP
authors.lastname: Sun
mesh_terms: D000328:Adult; D015925:Cryopreservation; D004624:Embryo Transfer / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D015999:Multivariate Analysis; D011247:Pregnancy; D018873:Pregnancy Rate; D011271:Pregnancy, Ectopic / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D020554:Sperm Injections, Intracytoplasmic; D055815:Young Adult