The objective of this study was to define the association between abnormal pronuclear numeration and molecular ploidy status. At the time of fertilization check on day 1 of embryo development, when there was no visible pronuclei (0PN; n=291), 56% were confirmed to be diploid and normally fertilized by SNP analysis. The remaining 41.9% were aneuploid and 2.1% contained only 23 haploid chromosomes. Upon analysis of the 1PN blastocysts (n=217), just over a third (36.4%) contained only 23 haploid chromosomes (23XO), with another third (31.8%) identified as aneuploid and the remaining third (31.8%) confirmed to be diploid and normally fertilized. In contrast, 50% of the 3PN blastocysts (n=172), showed the presence of a third set of 23 parental chromosomes, confirming triploidy with 41.9% identified also as aneuploid and interestingly, a small percentage (8.1%) confirmed to be diploid with normal fertilization. To date, there have been 74 euploid embryo transfers from zygotes originally identified with an alternate pronuclear numeration resulting in 16 ongoing pregnancies and 32 healthy live births. Accurate identification of haploid and tripoid zygotes is critical to prevent implantation failure and pregnancy loss and allows for the identification of all euploid embryos in a cohort which has the potential to increase cumulative live birth rates for infertility patients.