Comparison of endometrial preparation protocols (natural cycle versus hormone replacement cycle) for frozen embryo transfer (COMPETE): A study protocol for a randomised controlled trial

Xitong Liu, Wen Wen, Tao Wang, Ting Sun, Ting Wang, Na Zhang, Dan Pan, He Cai, Jinlin Xie, Xiaojuan Liu, Zan Shi, Rui Wang, Xiaofang Li, Na Lu, Rong Pan, Li Tian, Bin Meng, Haiyan Bai, Hanying Zhou, Pengfei QuDoudou Zhao, Ben W. Mol, Wentao Li, Juanzi Shi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Downloads (Pure)


Introduction Natural cycle (NC) and hormone replacement treatment (HT) are frequently used endometrial preparation protocols prior to frozen-thawed embryo transfer in ovulatory women. It is not clear which protocol results in a higher live birth rate. It has been suggested that there is an increased risk in maternal and perinatal morbidity following HT protocol due to the lack of corpus luteum. The objective of this trial is to compare the clinical outcomes of NC and HT protocols in frozen embryo transfer. Methods and analysis COMPETE is an open-label, single-centre, randomised controlled trial targeting to recruit 888 women, with 444 women each in two arms (1:1 treatment ratio). Women undergoing in vitro fertilisation scheduled for a frozen embryo transfer and have a regular menstrual cycle are eligible. Exclusion criteria include ovulation disorders and intrauterine adhesions. The primary outcome is live birth resulting from the first frozen embryo transfer after randomisation. Secondary outcomes include biochemical pregnancy, clinical pregnancy, multiple pregnancy, ongoing pregnancy, miscarriage, endometrial thickness, cycle cancellation, gestational diabetes mellitus, hypertensive disorders of pregnancy, antepartum haemorrhage, preterm birth, birth weight, large for gestational age, congenital anomaly and perinatal mortality. The data analysis will be following the intention-to-treat principle. Ethics and dissemination This study has been approved by the Institutional Review Board of Northwest women's and children's hospital (2020008). Written informed consent will be obtained from each participant before randomisation. The results of the trial will be presented via publications. Trial registration number ChiCTR2000040640.

Original languageEnglish
Article numbere063981
JournalBMJ Open
Issue number10
Early online date14 Oct 2022
Publication statusPublished - 14 Oct 2022

Bibliographical note

Funding Information:
This study is supported by General Projects of Social Development (2022SF-565).
BWM is supported by a NHMRC Investigator grant (GNT1176437). BWM reports consultancy for ObsEva. BMW has received research funding from Ferring and Merck. The other authors have none to declare.

We thank all the physicians, scientists, and embryologists
in our IVF clinic for their assistance with data collection as well the patients for
participating in this study


  • Reproductive medicine
  • Subfertility


Dive into the research topics of 'Comparison of endometrial preparation protocols (natural cycle versus hormone replacement cycle) for frozen embryo transfer (COMPETE): A study protocol for a randomised controlled trial'. Together they form a unique fingerprint.

Cite this