Impact of Luteinized Unruptured Follicles on Clinical Outcomes of Natural Cycles for Frozen/Thawed Blastocyst Transfer

Abstract

ObjectiveTo investigate the impact of luteinized unruptured follicles (LUF) on clinical outcomes of frozen/thawed embryo transfer (FET) of blastocysts.MethodsIn this retrospective cohort study, 2,192 patients who had undergone blastocyst FET treatment with natural cycles from October 2014 to September 2017 were included. Using propensity score matching, 177 patients diagnosed with LUF (LUF group) were matched with 354 ovulating patients (ovulation group). The LUF group was further stratified by the average LH peak level of 30 IU/L. Clinical pregnancy rate and live birth rate were retrospectively analyzed between the LUF and ovulation groups, as well as between LUF subgroups.ResultsAfter propensity score matching, general characteristics were similar in the LUF and ovulation groups. Clinical pregnancy rate in the LUF group was significantly lower than that in the ovulation group (47.46 vs. 58.76%, respectively, adjusted P = 0.01, OR 0.60, 95% CI 0.42–0.87). However, no significant difference was detected in live birth rate, although it was lower in the LUF group (43.50 vs. 50.00%, adjusted P = 0.19, OR 0.76, 95% CI 0.51–1.14). In the LUF subgroup analysis, both clinical pregnancy rate (43.02 vs. 62.30%, adjusted P = 0.02, OR 0.45, 95% CI 0.23–0.87) and live birth rate (37.21 vs. 59.02%, adjusted P = 0.01, OR 0.40, 95% CI 0.20–0.78) in the LH <30 IU/L subgroup were significantly lower than those in the LH ≥30 IU/L subgroup.ConclusionLUF negatively affected clinical outcomes of frozen/thawed embryo transfer of blastocysts, particularly when the LH surge was inadequate.

The true natural cycle frozen embryo transfer - impact of patient and follicular phase characteristics on serum progesterone levels one day prior to warmed blastocyst transfer

“…In regularly cycling women, a suboptimal preovulatory follicular development alongside low late-follicular/mid-cycle hormone profiles may result in a suboptimal luteal P 4 profile and endometrial milieu [ 19 , 20 ]. Unfortunately, there is a paucity of data on the correlation between follicular phase endocrine and ultrasonographic parameters and mid-luteal P 4 levels [ 19 , 21 – 23 ] and reproductive outcomes in spontaneous [ 24 – 27 ] and NC FET cycles [ 28 – 31 ].…”

Preparation of the endometrium for frozen embryo transfer: an update on clinical practices

“…Note that the study used a slow freezing and rapid thawing method, therefore, the results cannot be generalized to the more common vitrification method of embryo cryopreservation [ 80 ]. A current retrospective cohort study [ 81 ] reported that LUF had a detrimental effect on pregnancy outcomes in natural cycle FET of blastocysts, especially when the LH surge level was insufficient. These findings need to be confirmed by larger sample size studies or prospective randomized trials, and a deeper understanding of the mechanism behind LUF is necessary.…”

The FIGO Ovulatory Disorders Classification System

“…This circumstance begs the inclusion of intermittent anovulation in a broad-based, all-encompassing definition of ovarian dysfunction. An additional consideration is other aberrations in ovulatory function, such as the luteinized unruptured follicle (LUF) [7,8] and the luteal out of phase (LOOP) events [9] that represent, respectively, mechanical failure to release the mature oocyte and the premature recruitment of follicles in the luteal phase, each of which Glossary of terms used in this paper.…”