rFSH vs rFSH+rLH in Dydrogesterone-Based Progestin Protocol: A Prospective Study

This prospective observational study aims to evaluate how two routinely used gonadotropin strategies influence ovarian response and reproductive outcomes in women undergoing IVF treatment with a dydrogesterone-based Progestin-Primed Ovarian Stimulation (PPOS) protocol. In standard clinical practice, ovarian stimulation may be performed using recombinant FSH alone or a combination of recombinant FSH and recombinant LH. Both approaches are already used in daily care, and the choice of regimen is determined by the treating physician according to individual patient characteristics. The study does not assign treatments; instead, it observes and compares outcomes in patients receiving these medications as part of routine management.

Dydrogesterone is administered from Day 2 of the cycle to prevent premature LH surges, allowing controlled follicular growth. Participants will undergo regular ultrasound monitoring and bloodwork as part of their usual IVF treatment. When appropriate follicular maturation is achieved, final oocyte maturation will be triggered, followed by oocyte retrieval according to standard clinical protocols.

The primary focus of this study is to compare the number of mature (MII) oocytes obtained between the two gonadotropin regimens. Secondary outcomes include the number of good-quality blastocysts, implantation rate, and ongoing pregnancy rate, which together provide a comprehensive assessment of IVF success. Additional stimulation characteristics-such as follicle growth patterns, estradiol and LH levels, total gonadotropin dose, and duration of stimulation-will also be documented to explore differences in cycle dynamics.

No extra medications, procedures, or interventions will be required beyond routine IVF care. All data will be collected prospectively and analyzed to determine whether adding recombinant LH offers measurable clinical advantages compared with recombinant FSH alone in dydrogesterone-PPOS cycles.

Inclusion criteria

• Women aged 20 to 43 years.
• BMI < 30 kg/m².
• AMH > 1 ng/mL.
• Undergoing IVF/ICSI treatment with a dydrogesterone-based PPOS protocol.
• Women with regular menstrual cycles or clinically acceptable cycle pattern for stimulation.
• Ability to provide informed consent and comply with study procedures.
• Presence of at least one ovary and eligibility for controlled ovarian stimulation

Exclusion criteria

• Cycle cancellation due to lack of viable embryos.
• Prior or planned PGT-A in the same cycle.
• Adenomyosis diagnosed by ultrasound or MRI.
• Uncorrected uterine anomalies (e.g., bicornuate, unicornuate, didelphys uterus).
• Presence of hydrosalpinx.
• Use of oral contraceptives or luteal-phase estradiol within 3 months before stimulation.
• Refusal or inability to provide informed consent.
• Severe systemic disease or contraindication to ovarian stimulation.
• Prior bilateral oophorectomy