usromosomal abnormalities are responsible for a great deal of embryo wastage, which is reflected, at least partially, in decreased implantation and increased miscarriage in older women. To address this problem the transfer of only chromosomally normal embryos previously selected by preimplantation genetic diagnosis (PGD) has been proposed. We designed a multi-centre in-vitro fertilization (IVF) study to compare controls and a test group that underwent embryo biopsy and PGD for aneuploidy. Patients were matched retrospectively, but blindly, for average maternal age, number of previous IVF cycles, duration of stimulation, oestradiol concentrations on day +1, and average mature follicles. All these parameters were similar in test and control groups. Only embryos classified as normal for those chromosomes were transferred after PGD. The results showed that the rates of fetal heart beat (FHB)/embryo transferred between the control and test groups were similar. However, spontaneous abortions, measured as FHB aborted/FHB detected, decreased after PGD (P < 0.05), and ongoing pregnancies and delivered babies increased (P < 0.05) in the PGD group of patients. Two conclusions were obtained: (i) PGD of aneuploidy reduced embryo loss after implantation; (ii) implantation rates were not significantly improved, but the proportion of ongoing and delivered babies was increased.

No abstract

Fluorescence in-situ hybridization (FISH) for application in preimplantation genetic diagnosis (PGD) of aneuploidy has been used successfully, but stringent scoring criteria to score FISH signals have not been developed. In the present study a FISH protocol to simultaneously enumerate chromosomes X, Y, 13, 16, 18, and 21 was used to evaluate two different scoring criteria. The criteria consider hybridization signal size, shape, and vicinity to other signals and nuclear diameter. For this purpose, 74 embryos (412 blastomeres) donated for research had most or all of their cells analysed. The least error-prone criterion (9%) was selected for use in PGD cases. Some probes produced more errors than others, and these criteria may provide clues to improve these probes. The same probe solution was applied to 55 PGD cases and a total of 307 embryos. Of the non-transferred embryos, 67 were fully reanalysed and 1.5% (1/67) of them were falsely diagnosed as normal, while 19% (13/67) were falsely diagnosed as abnormal. Twelve of the patients became pregnant after PGD.

No abstract

Clinical egg cryopreservation has been applied during a 4-year period with some limited success. Mostly mature and a few immature eggs were frozen slowly and thawed rapidly in 1,2-propanediol and sucrose, and subsequently inseminated by intracytoplasmic sperm injection (ICSI). Three studies were performed in which: (i) it was established that 55% of aged unfertilized mature eggs survive freezing; (ii) in 22 cycles of thawed donated eggs cryosurvival was 24% with 15 cycles reaching transfer, and five pregnancies were initiated, one of which went to term at 39 weeks with fraternal twin boys, and one remains ongoing at 37 weeks; and (iii) in five cycles, where in-vitro fertilization patients had some of their own eggs frozen/ thawed, cryosurvival of mature eggs was poor at only 2.2%, although 44% sibling germinal vesicle (GV) stage eggs survived. A normal female infant delivered at 40 weeks arose from transfer of two embryos where GV eggs underwent in-vitro maturation post-thaw and were fertilized by ICSI. Pregnancies reported here and by others indicate a burgeoning awareness of the potential benefits of egg cryopreservation, prompting cautious optimism for the future of this technology.