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

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.