Objective: To evaluate the efficacy of subzonal insemination (SUZI) as applied to unfertilized oocytes after initial insemination.
Methods: Unfertilized oocytes at metaphase II obtained after conventional IVF from 14 patients were selected for reinsemination by SUZI. The fertilization rate and pregnancy outcome were assessed.
Results: Of the 57 unfertilized oocytes at metaphase II, 10 (17.5%) became fertilized after SUZI. Eight of the 10 (80%) oocytes showed normal fertilization with two pronuclei while the other two (20%) oocytes were polyspermic. Five (35.7%) of the 14 patients had embryo transfer resulting in two (14.3%) pregnancies. One patient had a spontaneous abortion and the other had a live birth at term.
Conclusion: Reinsemination of unfertilized oocytes by SUZI could be of value when fertilization fails after initial insemination.