OOPLASMIC TRANSFER IN MATURE HUMAN OOCYTES

Ooplasmic transplantation aimed at restoring normal growth in developm entally compromised oocytes and embryos was evaluated in seven couples (eight cycles) with multiple implantation failures. Two approaches we re investigated to transfer ooplasm from donor eggs at metaphase II (M II) stage into patient MII eggs: (i) electrofusion of a ooplasmic dono r fragment into each patient egg (three cycles), and (ii) direct injec tion of a small amount of ooplasm from a donor egg into each patient e gg (five cycles). Some donor eggs were used multiple times. Donor eggs were divided into two groups, one being used for ooplasmic extraction and the other one for egg donation. Cleaved embryos resulting from th e latter were cryopreserved, where numbers and satisfactory developmen t permitted. A second control group consisted of embryos derived from patient eggs after intracytoplasmic sperm injection without ooplasmic transfer. This was performed when sufficient number of eggs were avail able (n = 5). Donor eggs (n = 40) were evaluated cytogenetically after micromanipulation in order to confirm the presence of chromosomes. On e egg was anuclear and the recipient embryos were not transferred. Nor mal fertilization was significantly higher after injection of ooplasm (63%) in comparison with fusion (23%). Pronuclear anomalies appeared e nhanced after fusion with ooplasts. Embryo morphology was not improved in the three cycles with electrofusion and patients did not become pr egnant. An improvement in embryo morphology was noted in two patients after injection of ooplasm and both became pregnant, but one miscarrie d. A third pregnancy was established in the repeat patient, without ob vious embryo improvement. One baby was born and the third pregnancy is ongoing with a normal karyotype. Two other patients with male factor infertility had poor embryos after ooplasmic injection, but the donor embryo controls were also poor. The patients did not become pregnant a nd had no donor embryos frozen. Ooplasmic transfer at the MII stage ma y be promising in patients with compromised embryos; however, evaluati on of ooplasmic anomalies and optimization of techniques will require further investigation prior to widescale application.