POLAR BODY VS. BLASTOMERE BIOPSY FOR PGD. PB OR NOT PB? G. Altarescu¹, T. Eldar-Geva¹, B. Brooks¹, Y. Kaplan¹, M. Patt¹, E.J. Margalioth¹, A. Lahad², E. Levy-Lahad¹, P. Renbaum¹. 1) Zohar PGD Lab, and IVF unit, Shaare Zedek Medica Center, Jerusalem, Israel; 2) Department of Family Medicine, Hebrew University, Jerusalem, Israel.
   PGD may be performed by biopsy of polar bodies(PB) 1 and 2,or blastomeres from 6-8 cell embryos. PB biopsy allows PGD analysis without removing embryonal cells, and for inconclusive cases, a repeat analysis using a blastomere can be performed. Blastomere-PGD allows direct analysis of both maternal and paternal alleles, but is purportedly associated with higher rates of allele drop-out (ADO). We compared the efficiency of biopsy, molecular diagnosis, ADO, and pregnancy rate (PR) for PB vs. blastomere based PGD. Cases of maternal autosomal dominant (AD), X-linked, and autosomal recessive diseases underwent PB-PGD. Blastomere PGD was done for paternal AD diseases, and when an insufficient number of wild-type oocytes were diagnosed by PB analysis. Samples without results for at least one polymorphic marker on either side of the mutation in addition to the mutation itself (or another internal marker) were considered inconclusive. We analyzed 78 cycles of PGD (901 total biopsies) in 48 couples both by intention to treat and actual treatment.35% of cycles were PB only,50% were blastomere only, and 15% had combined PB and blastomere testing. Biopsy success rates were similar for both PB and blastomeres (95%). Successful molecular diagnosis was significantly higher for PB-PGD(88%), vs blastomere-PGD(76%,p=0.02). ADO rate in 947 reactions was significantly lower in PB (5%) vs. blastomeres (16%,p=0.001). Both by interntion to treat and by actual treatment, there was a trend towards higher PR per embryo transfer in PB-PGD (40%) vs blastomere-PGD (23%). The number of embryos transferred was significantly associated with PR (OR 2.4 per additional embryo, p=0.04),and significantly more embryos were available for transfer in PB-PGD vs. blastomere-PGD(p=0.02). PB-PGD leads to a lower ADO rate and a significantly higher diagnosis rate, compared to blastomere-PGD. Pregnancy rate was higher with PB-PGD, possibly because PB-PGD yielded a significantly higher number of embryos available for transfer.