Dados do Trabalho

Title

Cytogenetic analysis in couple with recurrent pregancy loss: The state of art

Objective

To present the prevalence of chromosomal abnormalities detected by conventional karyotyping in couple with recurrent pregnancy loss (RPL) and their products of conception (POC).

Methods

Literature search was perfomed using health databases Medline, Lilacs, Scielo, and PubMed, with the keywords "Cytogenetic analysis" AND "Abortion, Habitual" AND "Embryo loss". Articles in Portuguese, Spanish and English available on virtual platforms were included. Only papers published within the last 5 years were selected and the duplicated ones were removed. Cases reports were also excluded. Cross-sectional studies, cohort studies, and literature reviews were considered eligible for inclusion.

Results

87 papers were found. After a thorough reading of the potentially relevant articles, 8 studies met the inclusion criteria and were used to produce this review.
Chromosomal anomalies are found in more than half of early pregnancy losses. Cytogenetic analysis holds clinical relevance by allowing couples to make decisions after finding out whether a new conception is viable or not. karyotype has limitations as a method of cytogenetic analysis, especially with regards to analysis of products of conception (POC), with frequent culture failure, contamination of the material by maternal cells, and low resolution that does not allow the detection of subtle chromosomal anomalies. Therefore, chromosomal microarray analysis (CMA) has been considered as the first-tier test for genetic investigation of pregnancy loss but it is still costly and difficult to access.
The prevalence of fetal chromosomal aberrations detected in cases of Recurrent Pregnancy Loss (RPL) ranged from 40.4% to 61% in the analyzed papers. The main abnormalities observed were trisomies of chromosomes 13, 16, 18, 21, and monosomy of the X chromosome. Regarding the karyotype investigation of the evaluated couples, a variation of 3.74% to 7.4% of abnormalities was found. The main structural aberrations were balanced translocations, Robertsonian translocations, and inversions, respectively. These abnormalities were more frequent in women than in men, and the chromosomically affected women were on average 3 years younger than the unaffected ones. Another finding was the positive correlation between the number of previous miscarriages and the frequency of chromosomal abnormalities. Furthermore, one of the studies infers that if the fetal karyotype result is normal, the analysis of the genetic material of the parents is unnecessary since it guarantees that the spontaneous abortion is not related to any hereditary chromosomal abnormality, and it is also cost-effective. If the cytogenetic test of the Product of Conception (POC) is not available, a peripheral blood test for the karyotype of both partners should be considered. Even in cases of abortion after assisted conception with pre-implantation genetic diagnosis, the evaluation should include the analysis of the peripheral karyotype of the parents and the POC.

Conclusion

Cytogenetic analysis of couples with RPL showed a predominance of structural chromosomal abnormalities in females and the occurrence of these alterations at a younger age compared to women without chromosomal anomalies. Therefore, genetic counseling and cytogenetic analysis should be part of the investigation for any couple, as it allows better support during the grieving process, in addition to being economically viable.

Keywords

"Cytogenetic analysis" AND "Abortion, Habitual" AND "Embryo loss"