Live birth rates with a freeze-only strategy versus fresh embryo transfer: secondary analysis of a randomized clinical trial

Lan N. Vuong*, Toan D. Pham, Vinh Q. Dang, Tuong M. Ho, Vu N.A. Ho, Robert J. Norman, Ben W. Mol

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Research question: What are the roles of serum progesterone and endometrial thickness as biomarkers in the decision between a freeze-only and fresh embryo transfer in IVF for women without polycystic ovary syndrome (PCOS)? Design: This was a secondary analysis of a randomized controlled trial including 782 couples who were followed up until the end of the first completed cycle. Couples scheduled for their first or second IVF cycle with a FSH/gonadotrophin-releasing hormone antagonist protocol were randomized to a freeze-only (n = 391) or fresh embryo transfer (n = 391) strategy. The endpoint for this analysis was live birth rate (LBR) after the first embryo transfer. Results: There was no significant difference in LBR after the first cycle between a freeze-only and fresh transfer strategy. When serum progesterone levels at trigger were in the third quartile (Q3, 1.14–1.53 ng/ml), LBR was significantly higher in the freeze-only versus fresh transfer group (P = 0.01); when serum progesterone was ≥1.14 ng/ml, LBR was significantly better in the freeze-only group (37.4% versus 23.8% in the fresh transfer group; P = 0.004). LBRs in the freeze-only and fresh embryo transfer groups were similar across all quartiles of endometrial thickness, although a small advantage for freeze-only in women with a very thin endometrium could not be excluded. Conclusions: Serum progesterone level on the day of trigger may have potential as a biomarker on which to base a prospective decision about whether to use a freeze-only or fresh embryo transfer strategy in women undergoing IVF.

Original languageEnglish
Pages (from-to)387-396
Number of pages10
JournalReproductive Biomedicine Online
Issue number3
Early online date20 Dec 2018
Publication statusPublished - 1 Mar 2019

Bibliographical note

This study was funded by My Duc Hospital, Ho Chi Minh City, Vietnam.

Data Availability Statement

Supplementary material associated with this article can be found in the online version at doi: 10.1016/j.rbmo.2018.12.012.


  • Biomarkers
  • Endometrial thickness
  • Freeze-only protocol
  • IVF
  • Progesterone
  • Randomized clinical trial


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