Comprehensive chromosome screening of polar bodies and blastocysts from couples experiencing repeated implantation failure

Objective

To identify and transfer cytogenetically normal embryos after screening all chromosomes of first and second polar bodies (PBs) or trophectoderm samples with the use of comparative genomic hybridization.

Design

Clinical research study.

Setting

In vitro fertilization clinic referring samples to a specialist preimplantation genetic diagnosis laboratory.

Patient(s)

Thirty-two couples with repeated implantation failure.

Intervention(s)

Zygotes from patients with repeated implantation failure and poor response to ovarian stimulation underwent PB biopsy. Patients with repeated implantation failure who were candidates for blastocyst transfer received trophectoderm biopsy. Zygotes or blastocysts were vitrified while chromosome analysis took place. Euploid embryos were transferred during a subsequent cycle.

Main Outcome Measure(s)

Cytogenetic status and implantation and pregnancy rates.

Result(s)

The oocyte and blastocyst aneuploidy rates were 65.5% and 45.2%, respectively. Abnormalities affecting all chromosomes were detected. Implantation and pregnancy rates for the patients with PB biopsy were 11.5% and 21.4%, respectively, whereas for patients receiving blastocyst analysis they were 58.3% and 69.2%.

Conclusion(s)

Initial results for patients of advanced maternal age (39.8 years) with repeated implantation failure and poor ovarian response were encouraging. However, further study is required to confirm whether or not screening is beneficial. Blastocyst analysis was associated with high pregnancy rates, suggesting that comprehensive chromosome screening may assist patients with repeated implantation failure capable of producing blastocysts in achieving pregnancies.

Key Words: Repeated implantation failure, oocyte, polar body, embryo, blastocyst, preimplantation genetic screening, comparative genomic hybridization, chromosome, aneuploidy, vitrification