Elective transfer of embryos selected on the basis of first polar body morphology is associated with increased rates of implantation and pregnancy

Objective: To determine the relationship between first polar body morpholog y and implantation rate and pregnancy rate (PR), to facilitate decision mak ing concerning elective ET. Design: Prospective, randomized study. Setting: Fertility center. Patient(s): One hundred fifty-eight consecutive patients (173 intracytoplasmic sperm injection cycles) resulting in embryo transfers. Intervention(s): In our study group, priority in ET was given to embryos de rived from well-shaped first polar bodies, whereas selection of embryos for transfer in the control group was based exclusively on the degree of embry o fragmentation. Main Outcome Measure(s): Total numbers of implantations and pregnancies, PR and implantation rate, and rates of multiple pregnancy and miscarriage. Result(s): In the study cohort, 212 embryos were transferred. In the contro l group, 313 embryos were transferred. The implantation rate and PR were si gnificantly lower in the control group than in the study cohort. In additio n, the rate of multiple pregnancy was significantly higher in the study gro up. Conclusion(s): Elective transfer of embryos selected on the basis of first polar body morphology results in higher implantation and pregnancy rates. M ultiple pregnancy can be avoided by transferring a reduced number of embryo s selected on the basis of first polar body morphology. (Fertil Steril(R) 1 999,72:599-603. (C) 1999 by American Society for Reproductive Medicine.).