Late maturing oocyte rescue in poor-prognosis patients: delayed intracytoplasmic sperm injection results in more viable embryos

<b>Research question:</b> <br></br> Can delayed intracytoplasmic sperm injection (DICSI) in late maturing oocytes improve fertilization, blastocyst formation, pregnancy and live birth rates for poor-prognosis patients?<br></br> <br></br> <b>Design:</b> <br></br> Retrospective analysis of 2243 oocytes from 250 poor-prognosis patients who underwent 311 assisted reproductive technology (ART) cycles. Patients were offered DICSI to increase the number of embryos available for testing when over 50% of oocytes collected were immature on day 0, less than 50% of the injected oocytes were fertilized on day 1 or when patients were undergoing preimplantation genetic testing for aneuploidy.<br></br> <br></br> <b>Results:</b> <br></br> Fertilization and blastulation rates differed depending on the original assessment of the oocyte maturation stage. Euploidy rate did not differ between blastocysts derived from fertilized oocytes originally assessed as metaphase I (MI) or metaphase II (MII). A transferred blastocyst derived from a matured oocyte originally assessed as MI was as likely to result in a live birth as one from a MII oocyte. No differences in delivery method, gestation period or birth weight were found between intracytoplasmic sperm injection and DICSI. As a result of DICSI, at least 27 cycles (8.7%), which would have otherwise been unproductive, resulted in live births, with five ongoing pregnancies. <br></br> <br></br> <b>Conclusions:</b> <br></br> Both MI and germinal vesicle oocytes can complete maturation in vitro. Blastocysts produced from these are likely to be chromosomally normal compared with oocytes originally assessed as MII, and result in similar live birth rates. With no differences in birth outcomes, and DICSI increasing overall ART cycle success, this approach has value for poor-prognosis patients.