Prevalence of karyotype alterations in couples with recurrent pregnancy loss in a tertiary center in Brazil

TL;DR

This study found that about 8% of Brazilian couples with repeated miscarriages had chromosomal abnormalities, which were linked to older maternal age.

Contribution

The study reports a higher prevalence of chromosomal abnormalities in RPL couples in Brazil compared to previous literature.

Findings

Abnormal karyotypes were found in 7.8% of couples with recurrent pregnancy loss.

Numerical chromosomal anomalies were more common than structural ones.

Four women had low-grade Turner mosaicism, and maternal age was higher in couples with chromosomal alterations.

Abstract

To assess the prevalence and type of chromosomal abnormalities in Brazilian couples with recurrent pregnancy loss (RPL) and compare the clinical characteristics of couples with and without chromosome abnormalities.

We assessed the medical records of 127 couples with a history of two or more miscarriages, referred to a tertiary academic hospital in Belo Horizonte, Brazil, from January 2014 to May 2023. Karyotype was generated from peripheral blood lymphocyte cultures, and cytogenetic analysis was performed according to standard protocols by heat-denatured Giemsa (RHG) banding.

Abnormal karyotypes were detected in 10 couples (7.8%). The prevalence of chromosomal abnormalities was higher among females (6.3%) compared to males (2.0%), but this difference was not statistically significant (p=0.192). The mean number of miscarriages was. 3.3 ± 1.1 in couples with chromosome abnormalities and 3.1 ± 1.5 in couples without chromosome abnormalities (p=0.681). Numerical chromosomal anomalies (6 cases) were more frequent than structural anomalies. Four women presented low-grade Turner mosaicism. No differences were found between couples with and without karyotype alterations, except for maternal age, which was higher in the group with chromosome alterations.

The prevalence of parental chromosomal alterations in our study was higher than in most series described in the literature and was associated with increased maternal age. These findings suggest that karyotyping should be part of the investigation for Brazilian couples with RPL, as identifying the genetic etiology may have implications for subsequent pregnancies.