"Does serum estrogen level have an impact on outcomes in hormonal replacement frozen-warmed embryo transfer cycles?"

AIM: To evaluate the impact of serum estradiol (E2) levels on cycle outcomes in hormone replacement frozen embryo transfer (HR- FET) cycles. MATERIALS AND METHODS: We retrospectively analyzed 509 HR-FET cycles performed from September 2018 to September 2019. Patients were divided into 6 groups based on their E2 values measured a day before progesterone initiation . Group 1: <100 pg/mL, group 2: 100-200 pg/mL, group 3: 200 - 300 pg/mL, group 4: 300-400 pg/mL, group 5: 400-500 pg/mL, group 6: >500 pg/mL. Implantation rate (IR), clinical pregnancy rate (CPR), miscarriage rate (MR), multiple pregnancy rate (MPR) and ectopic pregnancy rates were compared between all groups. RESULTS: IR and CPR were similar between a wide range of E2 values, but when E2 values were more than 500 pg/mL there was a non significant fall in the IR (47.3% vs 48.3% vs 48.6% vs 47.8% vs 48.7% vs 39.6% p = .77) and CPR (63.6% vs 65.1% vs 65.6% vs 65.3% vs 65.6% vs 53.1% p = .692). MR was significantly high when E2 was less than 100 pg/mL (28.5%) and when E2 was more than 500 pg/mL (41.1%) (p = .02). MPR and ectopic pregnancy rates were similar between all the groups. CONCLUSION: Outcomes of FET cycles were similar between a wide range of E2 values (100-500 pg/mL). When E2 levels were less than 100 pg/mL or more than 500 pg/mL there was significant increase in the MR but the numbers in these groups are less and further studies are required to confirm these facts.

A prospective study of oral estrogen versus transdermal estrogen (gel) for hormone replacement frozen embryo transfer cycles.

AIM: This study was done to compare the efficacy of transdermal estrogen (gel) to oral estradiol in hormone replacement frozen embryo transfer cycles (HR- FET). MATERIALS AND METHODS: This was a prospective study conducted between March 2019 and December 2019. We included 294 HR FET cycles: 156 cycles using oral estrogen tablets (oral group) and 138 cycles using transdermal gel (17 beta estradiol 0.06% w/w) (gel group). Primary objective of this study was to compare endometrial thickness (ET) on the day of progesterone start between the two groups. Our secondary objective was to compare implantation rates (IR), clinical pregnancy rates (CPR), miscarriage rates (MR), duration of estrogen administration, estradiol (E2) levels before the start of progesterone, cycle cancellation rates, patient satisfaction score and undesirable side effects between both the groups. RESULTS: There was no significant difference in the ET, IR, CPR, MR and duration of E2 administration and cycle cancellation rates between both the groups. Patient satisfaction score was significantly higher (8.02 ± 1.07 vs 6.96 ± 0.99 p < .01) and side effects were significantly lower (18.1% vs 55.1%, p≤.01), in the gel group compared to the oral group. CONCLUSION: This study concluded that transdermal estrogen (gel) is equally efficacious as oral estrogen in HR FET cycles with transdermal gel having an added benefit of better patient comfort with less side effects and better safety profile.