Cytogenetic Analysis of 570 Couples with Recurrent Pregnancy Loss: Reporting 11 Years of Experience

Patterns of Cytogenomic Findings from a Case Series of Recurrent Pregnancy Loss Provide Insight into the Extent of Genetic Defects Causing Miscarriages

Background  A retrospective study was performed to evaluate the patterns of cytogenomic findings detected from a case series of products of conception (POC) in recurrent pregnancy loss (RPL) over a 16-year period from 2007 to 2023. Results  This case series of RPL was divided into a single analysis (SA) group of 266 women and a consecutive analysis (CA) group of 225 women with two to three miscarriages analyzed. Of the 269 POC from the SA group and the 469 POC from the CA group, a spectrum of cytogenomic abnormalities of simple aneuploidies, compound aneuploidies, polyploidies, and structural rearrangements/pathogenic copy number variants (pCNVs) were detected in 109 (41%) and 160 cases (34%), five (2%) and 11 cases (2%), 35 (13%) and 36 cases (8%), and 10 (4%) and 19 cases (4%), respectively. Patterns with recurrent normal karyotypes, alternating normal and abnormal karyotypes, and recurrent abnormal karyotypes were detected in 74 (33%), 71 (32%), and 80 (35%) of consecutive miscarriages, respectively. Repeat aneuploidies of monosomy X and trisomy 16, triploidy, and tetraploidy were detected in nine women. Conclusions  A comparable spectrum of cytogenomic abnormalities was noted in the SA and CA groups of RPL. A skewed likelihood of 2/3 for recurrent normal and abnormal karyotypes and 1/3 for alternating normal and abnormal karyotypes in consecutive miscarriages was observed. Routine cytogenetic analysis should be performed for consecutive miscarriages. Further genomic sequencing to search for detrimental and embryonic lethal variants causing miscarriages and pathogenic variants inducing aneuploidies and polyploidies should be considered for RPL with recurrent normal and abnormal karyotypes.

The pattern of chromosomal abnormalities in recurrent miscarriages: a single center retrospective study

BACKGROUND

Chromosomal abnormalities are more common in first trimester recurrent miscarriages (RM). Chromosomal anomalies affect approximately 2%-8% of couples with RM.

OBJECTIVES

Evaluate the spectrum and the frequencies of chromosomal anomalies in RM.

DESIGN

A retrospective hospital record-based descriptive study.

SETTING

A tertiary care center in Turkey.

PATIENTS AND METHODS

We studied couples with RM between October 2020 and January 2022. Relevant family and medical history, clinical examination and the results of karyotype were statistically analyzed.

MAIN OUTCOME MEASURES

Prevalence and types of chromosomal aberrations in couples with RM. SAMPLE SİZE: 362 couples with a history of RM RESULTS: Among the 362 couples, 14 cases (3.86%) had chromosome abnormalities. Eight cases (57.14%) were structural anomalies and six cases (42.86%) were numerical chromosomal aberrations. We found five balanced translocations (67.5%) and three Robertsonian translocations (37.5%). The prevalence of polymorphic variants was 51/362 (14.1%).

CONCLUSIONS

This study supports the conclusion that clinicians should understand the importance of chromosome analysis in these couples and direct them to karyotyping after two abortions in order to exclude the possibility of a genetic cause of RM.

LIMITATIONS

Single-center study and retrospective.

CONFLICT OF INTEREST

None.

Recurrent spontaneous abortion related to balanced translocation of chromosomes: two case reports

Background

Recurrent spontaneous abortion (RSA) is often idiopathic, but structural chromosomal abnormality is an important nosogenesis. Balanced translocations or inversions can lead to unbalanced gametes depending on the specific recombination and segregation patterns during meiosis. An unbalanced karyotype in the conceptus of a couple when one partner has a structural chromosomal abnormality may result in failure to implant, miscarriage, or ongoing pregnancy of a fetus with an unbalanced karyotype.

Case presentation

We report two rare Han cases of RSA associated with balanced translocation of chromosomes. In case 1, a women who had had four spontaneous abortions, the karyotype was 46, XX, t (4;7) (q31;q22). In case 2, a women who had two spontaneous abortions and one stillborn fetus, the karyotype was 46, XX, t (3;15) (q12;p11.2), inv (5) (P13q13). The abnormal karyotype was not found in other chromosomes.

Conclusions

It is very important that couples with more than two miscarriages be provided with chromosomal analysis. Referring couples for karyotyping will rule out or confirm possible hereditary etiology and the source of chromosomal abnormalities in recurrent miscarriages.