A live birth of activated one-day-old unfertilized oocyte for a patient who experienced repeatedly near-total fertilization failure after intracytoplasmic sperm injection.

Total or near-total fertilization failure after intracytoplasmic sperm injection (ICSI) is a rare event, but it occurs repeatedly because of sperm defects in activating oocyte. The case presents a successful pregnancy and live birth after calcium ionophore A23187 (A23187) activation on one-day-old unfertilized oocytes in a patient whose husband suffered oligoasthenoteratozoospermia, and who had experienced repeated near-total fertilization failure after ICSI. In the second ICSI cycle, only one oocyte was fertilized while nine were unfertilized. Oocyte activation with A23187 were performed on the one-day-old unfertilized oocytes after ICSI and resulted in fertilization and embryo transfer. A clinical pregnancy was achieved and a healthy baby was born. To our knowledge, this is the first reported case of a healthy birth after oocyte activation on the one-day-old unfertilized oocyte. This indicates that "rescue oocyte activation" on one-day-old unfertilized oocytes after ICSI may be helpful for preventing total or near-total fertilization failure after ICSI.