Maximizing pregnancy rates and limiting higher-order multiple conceptions by determining the optimal number of embryos to transfer based on quality

Abstract

Objective: To define statistical thresholds for the number of embryos to be transferred to achieve an optimal pregnancy rate and keep higher-order multiple conceptions (pregnancy with more than two fetal sacs with cardiac activity) within an acceptable limit.

Design: A retrospective review of patient records.

Setting: Private practice assisted reproductive technology (ART) facility.

Patient(s): Seven hundred fifty-four consecutive patients who underwent IVF-ET from 1994-1996.

Intervention(s): Embryo grading and score system used on day 3 of embryo transfer.

Main outcome measure(s): Implantation, pregnancy, and multiple conception rates.

Result(s): For women < or =35 years old, transfer of up to four poor-quality, two fair-quality, or two good-quality embryos is optimal to eliminate any risk of higher-order multiple pregnancies. Transfer of four poor-quality, three fair-quality, or two good-quality embryos is recommended for women 36 to 39 years old. In women who are > or =40 years old, five embryos need to be transferred regardless of embryo quality.

Conclusion(s): The mean cumulative embryo score can be used as a reference to determine an optimal number of embryos to transfer and to predict pregnancy outcome.