Background:Chromosomal abnormalities are the main cause of early miscarriages. Objective: The aim of this cross-sectional cohort study was to investigate the chromosomal abnormalities in first trimester spontaneous miscarriages in a Greek population. Methods:Spontaneous abortion samples from a single genetic center in Greece were analyzed via conventional karyotype analysis and quantitative fluorescent polymerase chain reaction (QF-PCR). All samples were accompanied by maternal blood samples to exclude contamination. Results:The results of the present study showed that 83 out of the 198 available samples (41.9%) had an abnormal karyotype. The majority of embryos suffered from numerical chromosomal abnormalities (90.4%). Autosomal trisomy (54.2%) was the most frequent chromosomal abnormality, while trisomies 16 and 22 (seven cases) were the commonest karyotype anomalies. Nine fetuses (10.8%) suffered numerical abnormalities of sex chromosomes (all cases with 45, X), while 12 of fetuses (14.5%) were diagnosed with triploidy (five males with 69, XXY and seven females with 69, XXX). All miscarriages following IVF and presenting with abnormal karyotype were diagnosed with numerical abnormalities. Finally, a fetus with double trisomy (14 and 21) and a rare case of coexistence of Klinefelter (XXY) and Edwards (trisomy 18) syndromes were observed. Conclusions:Cytogenetic analysis of products of conception is an important step involved in investigating the causes of miscarriages. In this study of spontaneous miscarriages, the incidence and types of chromosome aberrations are presented for the first time in a Greek population.