protocolSection identificationModule nctId: NCT06372119, orgStudyIdInfo id: 13/23/DD-BVMD, briefTitle: Letrozole-stimulated Cycle Strategy Versus Artificial Cycle Strategy (LETSACT), statusModule overallStatus: NOT_YET_RECRUITING, startDateStruct date: 2024-04, primaryCompletionDateStruct date: 2026-04, completionDateStruct date: 2026-04, studyFirstPostDateStruct date: 2024-04-17, lastUpdatePostDateStruct date: 2024-04-17, sponsorCollaboratorsModule leadSponsor name: Mỹ Đức Hospital, class: OTHER, descriptionModule briefSummary: The goal of this randomized clinical trial is to evaluate the effectiveness of the letrozole-stimulated cycle strategy versus the artificial cycle strategy for endometrial preparation in women with irregular menstrual cycles after one cycle of endometrial preparation. The primary question it aims to answer is:• Does the letrozole-stimulated cycle strategy for endometrial preparation result in a higher live birth rate compared to the artificial cycle strategy in women with irregular menstrual cycles after one cycle of endometrial preparation?Participants will undergo screening before endometrial preparation for frozen embryo transfer, following which they will be randomly assigned to one of two groups: LETS or AC. In the LETS group, investigators will prescribe Femara® 2.5 milligrams (Novartis, Switzerland) at a dose of 5 milligrams/day for 5 days to stimulate follicular development and Cyclogest® 400 milligrams (Actavis, UK) at a dose of 800 milligrams/day for luteal phase support. In contrast, the AC group will receive Valiera® 2 milligrams (Laboratories Recalcine, Chile) starting with a dose of 6 milligrams/day, up to a maximum dose of 12 milligrams/day) and Cyclogest® 400 milligrams (Actavis, UK) at a dose of 800 milligrams/day. Researchers will compare the LETS and AC groups to determine if there are differences in live birth rates., conditionsModule conditions: Embryo Transfer, conditions: Irregular Menstruation, conditions: Letrozole, conditions: Hormone Replacement Therapy, designModule studyType: INTERVENTIONAL, phases: NA, designInfo allocation: RANDOMIZED, interventionModel: PARALLEL, primaryPurpose: TREATMENT, maskingInfo masking: NONE, enrollmentInfo count: 480, type: ESTIMATED, armsInterventionsModule interventions name: Letrozole-stimulated cycle strategy (LETS), interventions name: Artificial cycle strategy (AC), outcomesModule primaryOutcomes measure: Live birth rate after one cycle of endometrial preparation, secondaryOutcomes measure: Positive pregnancy test after one cycle of endometrial preparation, secondaryOutcomes measure: Clinical pregnancy after one cycle of endometrial preparation, secondaryOutcomes measure: Ongoing pregnancy after one cycle of endometrial preparation, secondaryOutcomes measure: Multiple pregnancy after one cycle of endometrial preparation, secondaryOutcomes measure: Implantation rate after one cycle of endometrial preparation, secondaryOutcomes measure: Cycle cancellation rate, secondaryOutcomes measure: Ectopic pregnancy rate after one cycle of endometrial preparation, secondaryOutcomes measure: Threatened miscarriage rate before 12 weeks of gestation after one cycle of endometrial preparation, secondaryOutcomes measure: Early miscarriage rate after one cycle of endometrial preparation, secondaryOutcomes measure: Late miscarriage rate after one cycle of endometrial preparation, secondaryOutcomes measure: Gestational age at birth, secondaryOutcomes measure: Onset of labor, secondaryOutcomes measure: Mode of delivery, secondaryOutcomes measure: Very low birth weight, secondaryOutcomes measure: Low birth weight, secondaryOutcomes measure: High birth weight (macrosomia), secondaryOutcomes measure: Very high birth weight (macrosomia), secondaryOutcomes measure: Gestational diabetes (GDM), secondaryOutcomes measure: Hypertensive disorders of pregnancy, secondaryOutcomes measure: Preterm birth, secondaryOutcomes measure: Stillbirth, secondaryOutcomes measure: Antepartum hemorrhage, secondaryOutcomes measure: Postpartum hemorrhage, secondaryOutcomes measure: Small for gestational age (singleton/twins), secondaryOutcomes measure: Large for gestational age (singleton/twins), secondaryOutcomes measure: Birth weight, secondaryOutcomes measure: Congenital anomalies, secondaryOutcomes measure: NICU admission, secondaryOutcomes measure: Reason for NICU admission, secondaryOutcomes measure: Neonatal mortality rate, eligibilityModule sex: FEMALE, minimumAge: 18 Years, maximumAge: 42 Years, stdAges: ADULT, contactsLocationsModule, hasResults: False