biostudies-literatureUnknown112(11)Picchetta LTriploid and haploid conceptions are not viable and are a common occurrence in humans, where they account for 10% of all pregnancy losses. Despite the parent of origin being important in the etiology of the pregnancy, our knowledge of their causes is limited, especially at the point of conception. Using a dataset of 96,660 biopsies and a validation dataset of 44,324 from human blastocyst embryos generated by intracytoplasmic sperm injection, we estimate that 1.1% of human conceptions (n = 1,063) contain extra or missing chromosome sets in zygotes. In our cohort of intracytoplasmic-sperm-injection-derived embryos, where the risk of polyspermy is inherently lower compared to natural conception, we identify for the first time a maternal age effect, with a 1.046-per-year increased risk in tripAmerican journal of human genetics2665-2678https://www.ebi.ac.uk/biostudies/studies/S-EPMC12808983biostudies-literatureMaternal age and genome-wide failure of meiotic recombination are associated with triploid conceptions in humans.PMC12808983Garcia-Velasco JAJobanputra VParaboschi EMCarmi SMounts EHoffmann ERPicchetta LEscriba Perez MJZhan YUbaldi FMGill PCapalbo AMolinaro TOttolini CSRienzi LFBabariya DTao XVallejo CMMulas FWhitehead CPellicer AfalseMaternal age and genome-wide failure of meiotic recombination are associated with triploid conceptions in humans.Triploid and haploid conceptions are not viable and are a common occurrence in humans, where they account for 10% of all pregnancy losses. Despite the parent of origin being important in the etiology of the pregnancy, our knowledge of their causes is limited, especially at the point of conception. Using a dataset of 96,660 biopsies and a validation dataset of 44,324 from human blastocyst embryos generated by intracytoplasmic sperm injection, we estimate that 1.1% of human conceptions (n = 1,063) contain extra or missing chromosome sets in zygotes. In our cohort of intracytoplasmic-sperm-injection-derived embryos, where the risk of polyspermy is inherently lower compared to natural conception, we identify for the first time a maternal age effect, with a 1.046-per-year increased risk in trip2025-01-01T00:00:00Z2025 Nov2026-06-12T05:05:13.976Z2026-06-12T03:08:06.252ZS-EPMC128089834109290810.1016/j.ajhg.2025.09.014