IVF Outcomes With Time-Lapse Culture: Comparison Between PPOS and GnRH Antagonist Protocols

The goal of this clinical trial is to compare two ovarian stimulation protocols used in in vitro fertilization (IVF): the fixed Progestin-Primed Ovarian Stimulation (PPOS) protocol and the GnRH Antagonist protocol. The study will evaluate IVF outcomes and embryo development patterns using time-lapse embryo monitoring technology. The main questions the study aims to answer are: * Does the fixed - PPOS protocol achieve similar numbers of mature eggs, good-quality embryos, and clinical outcomes compared to the GnRH Antagonist protocol? * Are there differences in embryo development patterns (morphokinetics) between the two protocols when monitored by time-lapse imaging? * How does embryo quality (KIDScore) compare between the two protocols? Study Design: Researchers will randomly assign 148 women undergoing IVF to two groups: * PPOS group (n=74): Will receive FSH injections (oral Duphaston 20mg daily) starting from day 2-3 of the menstrual cycle * GnRH Antagonist group (n=74): Will receive FSH injections (Orgalutran 0.25mg injections) when follicles reach ≥14mm Participants will: * Undergo controlled ovarian stimulation with their assigned protocol for approximately 10-12 days * Have regular ultrasound monitoring and blood tests to track follicle development * Undergo egg retrieval procedure when follicles are mature * Have all embryos cultured in the EmbryoScope time-lapse incubator with continuous monitoring * Have embryos frozen on Day 5/6 for future transfer Study Location: Department of Assisted Reproduction and Andrology, Hanoi Obstetrics and Gynecology Hospital Study Duration: January 2026 - June 2028