This is a randomized, controlled clinical trial with a two-sided superiority hypothesis. The study evaluates whether a 12-week pre-treatment with semaglutide prior to ovarian stimulation improves the number of good-quality blastocysts in overweight and obese women undergoing in vitro fertilization (IVF), compared to no pre-treatment.

Overweight and obese women (BMI 27-40 kg/m²) aged ≤38 years with adequate ovarian reserve (AMH ≥1 ng/mL or AFC ≥6) will be enrolled. Participants will be randomized in a 1:1 ratio to receive either 12 weeks of semaglutide pre-treatment (intervention group) or no pre-treatment (control group) before undergoing standard ovarian stimulation. Embryos will be cultured to the blastocyst stage and cryopreserved (freeze-all strategy). In the semaglutide group, embryo transfer will occur after an 8-week washout from the last semaglutide dose. Primary outcome: number of good-quality blastocysts on day 5. Secondary outcomes: embryo morphokinetics, fertilization rate, number of MII oocytes, number of COCs, total blastocyst formation rate, number of cryopreserved embryos, and pre/post semaglutide changes in weight, BMI, waist circumference, AMH, and AFC. The study has been designed with a superiority hypothesis to detect a difference of 1.5 good-quality blastocysts between groups, with 80% power and a two-sided alpha of 0.05.