title: The frozen-thawed embryo transfer timing determined by serum progesterone level: a retrospective follow-up study.
abstract: OBJECTIVE
  To compare the reproductive outcomes of frozen-thawed embryo transfer (FET) in nature cycle utilizing monitoring ovulation regimen (MOR) and monitoring progesterone (P) level regimen (MPR).
  
  
  METHODS
  A retrospective analysis of records of 224 women who received FET procedures.
  
  
  RESULTS
  MPR was used in 60.3% (135/224) of cycles and MOR in 39.7% (89/224) of cycles. The clinical pregnancy rate per transfer was 63.0% in the MPR group and 48.3% in the MOR group (p=0.030). The implantation rates were 42.6% and 35.1%, respectively (p=0.001). The ongoing pregnancy rates per transfer (at 12 weeks' gestation) were 54.1% and 41.6%, respectively (p>0.05). A logistic regression analysis showed that the type of natural cycle regimen was a predictor of clinical pregnancy rate (odds ratio, 1.996; 95% confidence interval, 1.123-3.549; p=0.019). Other significant variables affecting clinical pregnancy rate was number of top-quality embryos transferred.
  
  
  CONCLUSIONS
  Performing FET using MPR could achieve higher clinical pregnancy rate compared with MOR in a group of patients with the comparable demographic and cycle characteristics profile.
authors.affiliation: Reproductive Medicine Center, Guangzhou Women and Children's Medical Center, No. 9, Jinsui Road, Guangzhou 510623, Guangdong, People's Republic of China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Dong
authors.affiliation: Reproductive Medicine Center, Guangzhou Women and Children's Medical Center, No. 9, Jinsui Road, Guangzhou 510623, Guangdong, People's Republic of China. Electronic address: sunling2009@hotmail.com.
authors.forename: Ling
authors.initials: L
authors.lastname: Sun
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, The People's Republic of China.
authors.forename: Hanwang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Reproductive Medicine Center, Guangzhou Women and Children's Medical Center, No. 9, Jinsui Road, Guangzhou 510623, Guangdong, People's Republic of China.
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Reproductive Medicine Center, Guangzhou Women and Children's Medical Center, No. 9, Jinsui Road, Guangzhou 510623, Guangdong, People's Republic of China.
authors.forename: Yuehong
authors.initials: Y
authors.lastname: Jian
mesh_terms: D000328:Adult; D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer; D004717:Endometrium / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006080:Ovarian Follicle / Q000000981:diagnostic imaging; D010061:Ovulation Detection; D011247:Pregnancy; D018873:Pregnancy Rate; D011374:Progesterone / Q000097:blood*; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D011374:Progesterone
keywords: Cycle regimen; Frozen–thawed embryo transfer; Natural cycle; Vitrification