Effect of preovulatory progesterone elevation and duration of progesterone elevation on the pregnancy rate of frozen thawed embryo transfer in natural cycles

Prolonged exposure to preovulatory P elevation in frozen–thawed embryo transfer cycles in natural cycles adversely affected the pregnancy rates, similar to the fresh stimulated IVF treatment cycles.


Vivian Chi Yan Lee, M.B.B.S., Raymond Hang Wun Li, M.B.B.S., Joyce Chai, M.B.B.S., Tracy Wing Yee Yeung, M.B.B.S., William Shu Biu Yeung, Ph.D., Pak Chung Ho, M.D., Ernest Hung Yu Ng, M.D.

Volume 101, Issue 5, Pages 1288–1293



To assess the incidence of P elevation (PE) in natural cycles and evaluate its effect on frozen–thawed embryo transfer cycles performed in natural cycles (FET-NC).

Study Design:

Retrospective analysis.


A tertiary assisted reproductive unit.


Subfertile woman who did not conceive in their stimulated IVF cycle and underwent the first FET-NC cycle.


Achieved serum samples were assayed for P concentrations from the day of LH surge up to 3 days before the surge. The cutoff level of PE was defined as 5 nmol/L.

Main Outcome Measure(s):

Clinical and ongoing pregnancy rates.


The incidence of PE in natural cycles was 173 of 610 (28.4%). There were no significant differences in both clinical and ongoing pregnancy rates (39.0% vs. 37.3% and 32.5% vs. 31.7%) between those with vs. without PE on the day of LH surge. If PE lasted for 2 days or more, there was a significant reduction in the clinical pregnancy rate (39.4% vs. 20.7%). Using multivariate logistic regression, women’s age, PE for 2 days or more, and the number of top-quality embryos were the significant factors for clinical pregnancy rates in FET-NC.


The incidence of PE in FET-NC was similar to that in stimulated cycles. Progesterone elevation for 2 days or more before the LH surge impaired the clinical pregnancy rate of FET-NC, whereas PE on the day of LH surge only did not have such an adverse effect.

Read the full text at: http://www.fertstert.org/article/S0015-0282(14)00088-0/fulltext