The Effect of Second Biopsy on Pre-Implantation Genetic Diagnosis (PGD) Treatment Outcome

Introduction:

In an attempt to diagnose embryos when no clear genetic diagnosis is available from the biopsied cells, repeated biopsy may be performed.

Aim:

To examine whether there is a clinical benefit from performing second biopsy at different stages of embryonic development in case of failed genetic diagnosis.

Materials & Methods:

This retrospective study included 150 women undergoing IVF-PGD: the study group included 77 women that their embryos underwent re-biopsy: in 55 women, first sampling was taken from polar bodies (PBs) and second sampling from blastomeres (BB); in 22 women, first sampling was BB and second sampling was taken from trophectoderm (BLAST). The control group included 73 women who had a successful genetic diagnosis, matched in age, eggs number, type of genetic inheritance and embryonal age at the first biopsy to the women in the study group. Genetic diagnosis, clinical pregnancy rates (PRs), live-birth rates (LBRs) gestational age and birth weight were compared between the groups.

Results:

In the study group, second biopsy genetic diagnosis was received in 63/77 women (81.8%): 49/55 (89.1%) in the PB+BB group and 14/22 (63.6%) in the BB+BLAST group (P=0.019). PRs/ET were 23.4% in the study and 47.9% in the controls (P=0.002), 30.9% in the PB+BB group, and just 4.5% (1/22) in the BB+BLAST group (P=0.001). LBRs were 11/76 (14.5%) in study group, all from PB+BB biopsies and 29/73 (39.7%) in the controls. No significant difference between groups regarding gestational age and birth weight was found.

Conclusions:

We recommend re-biopsy cleavage-stage embryos when no genetic diagnosis could be achieved following PB biopsy.