Optimal parameters for determining the LH surge in natural cycle frozen-thawed embryo transfers

Abstract

BackgroundThere is no consensus on the exact parameters that define the LH surge for natural cycle frozen-thawed embryo transfers (NC-FET). Accurately determining the LH surge would affect the timing, and subsequently the success rates, of embryo transfer. Therefore, the aim of this study was to delineate the optimal levels and relationship for luteinizing hormone (LH) and estradiol in an effort to optimally identify the LH surge in NC-FET.MethodsIt is a retrospective study that was performed in an academic medical center. Patients who underwent blastocyst NC-FET who either had preimplantation genetic screening (PGS) or were <35 years old but did not undergo PGS (non-PGS) were included in separate analyses. They were divided into two groups: Group A included patients whose LH surge was defined as the first attainment of LH ≥ 17 IU/L during the follicular phase with a ≥30% drop in estradiol levels the following day; group B encompassed patients whose LH level continued to rise and the surge was defined as the highest serum LH level occurring a day after LH ≥ 17 IU/L despite a ≥ 30% drop in estradiol levels. The main outcomes measures were implantation and live birth rates.ResultsFour hundred-seven non-PGS and 284 PGS NC-FET were included. Among non-PGS cycles, group A was associated with significantly higher implantation rates (48.7% vs. 38.1%) and live birth rates (52.9% vs. 40.1%) compared to group B. In contrast, group A and B had comparable live birth rates among PGS cycles.ConclusionsAmong non-PGS cycles, measuring LH and estradiol levels the day after an LH ≥ 17 IU/L and defining the surge as the first day of LH ≥ 17 IU/L in the context of a ≥ 30% drop in estradiol the following day was associated with better NC-FET outcomes than defining the surge as the day representing the highest serum LH level despite a ≥30% drop in estradiol levels.

Is there a critical LH level for hCG trigger after the detection of LH surge in modified natural frozen-thawed single blastocyst transfer cycles?

“…There are several papers examining the optimal identification of LH surge and peak and the determination of embryo transfer day. Irani et al [ 5 ] showed that in true natural cycle, defining the surge as occurring on the day of an LH of ≥ 17 IU/L with a drop of ≥ 30% in estradiol (E2) levels, the following day was associated with better NC-FET outcomes than defining the surge as the day representing the highest serum LH level with a ≥ 30% drop in E2 levels on the same day [ 5 ]. A further related study by Reichman et al [ 6 ], in which the LH surge was defined by an LH level > 17 IU/L during the follicular phase with a subsequent dropping E2 level thereafter, also reported improved cycle outcomes with hCG booster given to patients within 1 day post-LH surge.…”

Follicular phase length has no influence on frozen-thawed embryo transfers in natural cycles

“…In addition, the optimal timing for NC-FET should be considered carefully with due consideration to the luteinizing hormone (LH) surge by serum monitoring in combination with a decrease in the serum estradiol level and an increase in the serum progesterone level, as well as the ultrasound detection of ovulation. Although most comparative studies have failed to reach a consensus on the definition of this event for NC-FET [ 7 – 9 ], it seems that different reproductive centers achieve their “ideal success rate” based on their own standards designed as per the encountered conditions. An intensive monitoring of spontaneous ovulation is essential for timely determination of NC-FET.…”

Seven Years of Vitrified Blastocyst Transfers: Comparison of 3 Preparation Protocols at a Single ART Center

“…In literature, there are various methods to establish the time of ovulation, considering serum LH elevation (<17 mIU/ml, or 2.5 times higher than previous determinations) considering estradiol drop, and increase in progesterone levels >1 ng /ml. or lower (42). A very recent publication (38) comparing natural and HR cycles when a follicle was > than 17 mm.…”