Aneuploidy rates in 510 pregnancies after ART – with and without polar body analysis

Abstract

OBJECTIVE: Chromosomal malsegregation during meiosis of human oocytes is presumed to be a dominant cause of numerical chromosomal aneuploidies of human concepti. As underlying mechanisms of origin, meiotic non-disjunction of bivalent chromosomes as well as unbalanced predivision of chromatids are discussed. The purpose of this study was to evaluate the frequency of aneuploidies in pregnancies conceived after ART with (163) and without (347) polar body analysis (PBA) using the fluorescence-in-situ-hybridization (FISH) technique. DESIGN: Retrospective analysis of 510 clinical pregnancies conceived after ART at the Fertility Center at Kaiser Wilhelm Memorial Church in Berlin from January 2005 to December 2007. Indications for PBA were previous unsuccessful ART cycles and/or advanced maternal age. MATERIALS AND METHODS: The outcome of 510 clinical pregnancies, all of them conceived after ART, were evaluated. In 163 pregnancies PBA was applied, using FISH probes for chromosomes 13, 16, 18, 21 and 22 [MultiVysionTMPB multicolour probe panel; Abbott]. Since July 2006 chromosome 15 [CEP15; Abbott] was tested, additionally. The outcome of all pregnancies is given in table 1.Table 1Outcome of 510 clinical pregnancies with (n 163) or without (n 347) PBA- PBA+ PBAClinicial pregnancies347163Ongoing7715Lost for follow up318Finished pregnancies239140Live birth188 (79 %)104 (74 %)Abortion / termination51 (21 %)36 (26 %) Open table in a new tab In 41 (47 %) of 87 abortive pregnancies karyotyping was undertaken. Out of these, 41 abortive pregnancies 23 have had no prior PBA and 18 have had prior PBA. In addition, karyotypes following amniocentesis of 11 ongoing pregnancies, all with prior PBA, were available. RESULTS: Numerical chromosomal aneuploidies concerning chromosomes tested by PBA could be found neither in abortive material nor in amniocytes in pregnancies conceived after ART with PBA. In contrast 35 % of abortive pregnancies after ART without PBA showed numerical chromosomal aneuploidies of chromosomes which could have been tested by means of PBA. CONCLUSIONS: PBA is a highly efficient method to avoid numerical aneuploidies of chromosomes tested in pregnancies achieved through ART. So far no numerical chromosomal aneuploidies could be detected for chromosomes which had been tested by PBA. As the number of cases studied is still small, further studies on the reliability of PBA should be undertaken. These findings may be important in counselling patients pregnant after ART with PBA, considering invasive prenatal diagnosis.