Frozen embryo transfer: Endometrial preparation by letrozole versus hormone replacement cycle: A randomized clinical trial

Abstract

Background: The endometrial preparation with stimulating natural cycles for frozen embryo transfer (FET) have benefits like lower cost and ease of use.
 Objective: Comparing the clinical outcome of letrozole versus hormone replacement (HR) for endometrial preparation in women with normal menstrual cycles for FET in artificial reproduction techniques.
 Materials and Methods: A total of 167 participants who had frozen embryos and regular ovulatory cycles were randomly divided into two groups for endometrial preparation. One group (82 women) was stimulated with letrozole 5mg/day and the other group (85 women) was hormonally stimulated by oral estradiol valerate (2 mg three times a day). All participants were followed serially by ultrasonography. Any patient who did not reach optimal endometrial thickness was excluded from the study. Implantation, biochemical and clinical pregnancy and abortion rate were reported.
 Results: There was no significant difference in the mean age, duration, and primary or secondary infertility, cause of the infertility, number, and quality of transferred embryos between the groups. The mean estradiol level on the day of transfer was 643 ± 217 in the HR group and 547 ± 212 in the letrozole group (P = 0.01), which was significantly different. The clinical pregnancy rate was 38.7 in the letrozole group, higher than the HR group (25.3) but not significantly different (P=0.06).
 Conclusion: For endometrial preparation in women with a normal cycle, letrozole yields higher pregnancy rate although it is not significant; due to its cost, ease in use, and lower side effects, letrozole is a good choice.
 Key words: Letrozole, Hormone replacement, Endometrial, Preparation, Frozen, Embryo.

Comparison of Pregnancy and Neonatal Outcomes of Single Frozen Blastocyst Transfer Between Letrozole-Induction and HRT Cycles in Patients With Abnormal Ovulation

“…Although there are many options for the preparation of the endometrium, there is still no uniform recommendation for the preparation of the FET endometrium for different groups of women to date (6)(7)(8). For patients with abnormal ovulation in particular, there have been few studies on FET protocols; notably, most of these studies focus only on the clinical pregnancy rate or LBR (9)(10)(11) and pay little attention to the regimen's safety for offspring. The most frequently used regimens for patients with abnormal ovulation are ovulation induction by letrozole and HRT.…”

Comparison of frozen-thawed embryo transfer protocols in patients with previous cycle cancellation due to uterine peristalsis: a pilot study

“…Zhang et al also demonstrated increased LBR in L-FET group when compared to AC-FET group in women with polycystic ovary syndrome in a retrospective study [29]. And lastly, CPR was significantly higher and E2 levels on ET day were significantly lower in L-FET group versus AC-FET group in a prospective randomized study in patients with normal menses [49]. In accordance with these studies, we demonstrated statistically significantly improved IR, CPR, LBR with a lower peak E2 levels and cancellation rates in L-FET cycles.…”

Effect of piroxicam administration on outcome of frozen–thawed embryo transfer: A randomized, double‐blinded, placebo‐controlled trial

“…The frozen–thawed ET and progesterone supplementation were done according to protocols reported in previous study 14 . Briefly, frozen embryos were transferred into the uterine cavity via the using sterile ET catheter under trans‐abdominal ultrasound guidance when the desired endometrial thickness has been achieved (7–9 mm).…”