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Live birth rates with a freeze-only strategy versus fresh embryo transfer in subjects with elevated progesterone levels during IVF: secondary analysis of a randomized clinical trial

Reprod Biomed Online. 2019;38(3):387-396 (IF 2.967) – 2018-12-20

LN Vuong1,2, TD Pham2, VQ Dang2, TM Ho2, VNA Ho2, RJ Norman3, BW Mol3,4

Published: December 20, 2018

Author information


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 vitro fertilization (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 follicle-stimulating hormone/gonadotropin-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; when serum progesterone was ≥1.14 ng/mL, LBR was significantly better in the freeze-only group (37.4% vs 23.8% in the fresh transfer group; p=0.004). Live birth rates 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.


in-vitro fertilization, freeze-only protocol, embryo transfer, progesterone, endometrial thickness, biomarkers, randomized clinical trial