How many embryos should be transferred? A validated score to predict ongoing implantation rate

Area of Science:

• Reproductive Medicine
• In Vitro Fertilization (IVF)

Background:

• Predicting IVF success is crucial for optimizing embryo transfer strategies.
• Current guidelines may not adequately address individual patient prognosis.

Purpose of the Study:

• To develop and validate a prognostic score for predicting IVF implantation rates.
• To guide the number of embryos transferred in IVF/ICSI cycles.

Main Methods:

• Multivariate analysis of clinical and biological parameters in 3211 fresh embryo transfers (retrospective).
• Prospective validation in 694 fresh embryo transfers.
• Assessment of ongoing implantation, pregnancy, multiple pregnancy, and live birth rates.

Main Results:

• Four key predictors identified: female age, oocyte retrieval/FSH dose ratio, attempt rank, and embryo morphology.
• Prospective use led to fewer embryos transferred (1.8 vs. 2.0, P<0.001).
• Significantly lower twin rates (9.7% vs. 17.3%, P<0.001) were observed without compromising live birth rates.

Conclusions:

• A personalized prognostic score can optimize embryo transfer decisions in IVF/ICSI.
• This approach aims for a reduced multiple pregnancy rate (<11%) while maintaining live birth rates.
• Individualized prognosis is preferable to a strict limit on embryo transfers, especially for poor prognosis cases.