Delivery of a chromosomally normal baby after the transfer of an embryo diagnosed as aneuploid by 24-chromosome preimplantation genetic screening

To demonstrate that a day 3 embryo diagnosed as aneuploid by preimplantation genetic screening is capable of producing a chromosomally normal child. A case report. A 34 year old Gravida 1, Para 1 delivered a son diagnosed with Persistant Mullerian Duct Syndrome (PMDS). Patient elected for Preimplantation Genetic Screening (PGS) for female karyotype and underwent In Vitro Fertilization. PGS of day 3 embryos was performed using single nucleotide polymorphism (SNP) microarray based 24-chromosome screening. A total of 9 embryos were biopsied and blastomeres sent off for analysis. One of the nine embryos was diagnosed as a normal 46;XX. The remaining 8 embryos were reported as aneuploid. The euploid embryo had poor morphological quality on day 3 and did not develop to the blastocyst stage. Patient was counseled not to transfer any of the remaining abnormal embryos, however, elected to transfer the highest quality blastocyst from the cohort of embryos regardless of the chromosome screening report. One good quality blastocyst reported as an aneuploid 42; XX; Nullisomy 8; Monosomy 7, 18 was transferred. A clinical pregnancy was reported with normal fetal heart motion. Chorionic villus sampling analysis revealed no evidence of chromosome abnormalities in the fetus confirming a normal 46; XX karyotype. A healthy baby was born at 36 weeks weighing 6.1 lbs and 18 3/4 inches long. This outcome indicates that normal embryos are possibly being misdiagnosed as abnormal by the commonly used preimplantation genetic screening of day 3 embryos. This, in turn, raises concern about the false positive rate being more elevated than what traditionally has been reported. Furthermore, it further solidifies the importance of moving on to day 5 trophectoderm biopsy to prevent the discarding of normal embryos. Aneuploidy screening of day 3 embryos should not be routinely offered to patients and should be used with caution.