M. Tsirigotis et al., LATE INTRACYTOPLASMIC SPERM INJECTION IN UNEXPECTED FAILED FERTILIZATION IN-VITRO - DIAGNOSTIC OR THERAPEUTIC, Fertility and sterility, 63(4), 1995, pp. 816-819
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.