Overview of Chromosome Abnormalities in First Trimester Miscarriages: A Series of 1,011 Consecutive Chorionic Villi Sample Karyotypes

Abstract

In order to contribute to the knowledge of type and frequency of chromosome abnormalities in early pregnancy losses, we analyzed the cytogenetic results from a large series of first trimester miscarriages, using a diagnostic approach with a high success rate and no maternal contamination. A total of 1,119 consecutive chorionic villi samples were obtained before evacuation, and karyotypes were prepared after short-term culture (STC). In 603 samples, a long-term culture (LTC) was also performed. The overall and individual frequencies of the different types of chromosome abnormalities were established, including placental mosaicisms, and their relationship with maternal age and gestational weeks was assessed. An abnormal karyotype was detected in 70.3% of the samples. Single autosomal trisomy was the most frequent abnormality (64.6% of the abnormal cases), followed by triploidy (13.1%) and monosomy X (10.4%). Chromosome rearrangements were found in 5.2%, combined abnormalities in 8.9%, and placental mosaicism in 3.5% of the cases with STC and LTC performed. Individual trisomies behaved differently with respect to maternal age and intrauterine survival. Due to the combination of STC and LTC, our study offers reliable information on the incidence and type of chromosome abnormalities and placental mosaicism in miscarriages and contributes to define the cytogenetic implication in their etiology.

Added value of chromosomal microarray analysis over karyotyping in early pregnancy loss: systematic review and meta‐analysis

“…Chromosomal anomalies are found in more than half of early pregnancy losses, and they are less common thereafter 3,4 . On karyotyping, autosomal trisomies are shown to be the most frequent anomalies (65%) associated with first-trimester miscarriage, followed by triploidy (13%) and monosomy X (10%) 5,6 . It has been shown that the etiologic analysis of a miscarriage has a major impact on the woman's/couple's future reproductive plans and prenatal care in future pregnancies 7 .…”

A new comprehensive paradigm for prenatal diagnosis: seeing the forest through the trees

“…Maternal cell contamination is prevented by obtaining a cleaner sample by means of transcervical chorionic villus sampling, appropriate cleaning of the sample, and the additional use of short‐term culture that allows only trophoblasts to divide. In a population of around 1000 such cases, we found a 90% karyotyping success rate, with a 70% incidence of chromosomal anomalies, possibly explained by the advanced maternal age of our studied population. CMA is emerging as an alternative method to overcome culture failure and potentially increase the success rate of analysis to 95%.…”

Chromosomal abnormalities detected by karyotyping and microarray analysis in twins with structural anomalies

“…The most common chromosomal abnormalities were trisomies, of which 96.4% (53/55) were of chromosomes 21, 18 and 13, since fetuses with such trisomies can survive until birth. In contrast, trisomies involving chromosomes 15, 16 and 22 are more likely to result in spontaneous miscarriage during the first trimester 25 . Structural anomalies in MC twins seem less likely to be related to chromosomal anomalies because the MC splitting may account for some of the observed anomalies.…”