LATE INTRACYTOPLASMIC SPERM INJECTION IN UNEXPECTED FAILED FERTILIZATION IN-VITRO - DIAGNOSTIC OR THERAPEUTIC

Objective: To evaluate fertilization potential of 24-hour-old unfertil ized oocytes using intracytoplasmic sperm injection and the pregnancy potential of resultant embryos. Design: Prospective observational stud y. Setting: Private infertility clinic, London, United Kingdom. Patien ts: Fifteen patients with a history of infertility who underwent treat ment with IVF and showed failure of fertilization on the day after ooc yte retrieval. Intervention: Assisted fertilization with intracytoplas mic sperm injection was carried out at 24 hours after oocyte retrieval . Results: A total of 121 metaphase II oocytes were subjected to intra cytoplasmic sperm injection. Of these, 9 were damaged (7%), 2 were pol yploidic (2%), and 58 showed normal fertilization (48%). Of the latter , 47 cleaved normally (81%). Forty embryos were transferred and three were cryopreserved. One patient conceived (7%) but in this case only o ne of three embryos transferred was from intracytoplasmic sperm inject ion. Conclusion: Late (24 hours) intracytoplasmic sperm injection can give good fertilization and cleavage rates but the potential of the ge nerated embryos to achieve pregnancy seems to be low.