On-Site Array CGH Applications in Clinical In Vitro Fertilization: Reproductive Outcomes and Impact on Cryopreservation of Non-transferred Human Embryos

摘要

Background: IVF pregnancy rates have trended upward although gains have been accompanied by unwelcome increases in pre-term delivery and multiple gestation. These adverse outcomes happen because multiple embryos are typically transferred during IVF. Integrating newer molecular cytogenetic techniques with IVF can optimize selection of a single embryo for transfer. Methods: The SurePlex DNA amplification system (BlueGnome Ltd; Cambridge, UK) was used on-site for whole genome amplification of human blastocyst trophectoderm (TE) cells obtained by biopsy. IVF patients (initial cycle, age <35, no prior miscarriage, normal karyotype) were prospectively randomized into two groups: In Group 1, embryos were selected on the basis of morphology and comprehensive chromosomal screening via array comparative genomic hybridization (aCGH) from d5 TE biopsy, while Group 2 embryos were assessed by morphology only. All patients underwent a single fresh blastocyst transfer on d6. For embryos in the aCGH group, only one euploid blastocyst was selected for transfer and surplus euploid blastocysts were vitrified. In the non-aCGH (control) group, a single blastocyst was selected for fresh transfer based on appearance only, with vitrification of any surplus blastocysts with satisfactory morphology. Results: Aneuploidy was identified in 191/425 of Group 1 balstocysts (44.9%). Control embryos (n=389) were assessed by microscopy only. A higher clinical pregnancy rate was observed in Group 1 patients compared to the control group (70.9 vs. 45.8%; p = 0.017). Only 64 (28.3%) surplus euploid embryos were frozen in Group 1 while 157 (40.4%) blastocysts were cryopreserved for Group 2 (p=0.017). Conclusion: These data underscore the intrinsic imprecision of IVF when conventional morphology is used alone to select embryos for transfer. Embryos evaluated with aCGH implant with greater efficiency and achieve clinical pregnancy more often than those selected without aCGH. Patients should be advised that aCGH screening may reduce the number of surplus embryos for cryopreservation.