The incidence of fetal chromosomal abnormalities in recurrent miscarriage couples with balanced translocation

Park, So Yeon; Kim, Kye Hyun; Choi, Bum Chae; Kang, Inn Soo; Yang, Kwang Moon; Yoo, Keun Jai; Song, In Ok

Abstract

OBJECTIVES
The most common chromosomal abnormality contributing to recurrent abortion is the balanced chromosomal translocation. However the exact incidence of fetal losses are still unknown. The objectives of this study were to evaluate the incidence of fetal chromosomal abnormalities and outcome of pregnancy in recurrent miscarriage couples with balanced translocation. DESIGN: A retrospective analysis of recurrent spontaneous abortion patients with balanced chromosomal translocation.
MATERIALS AND METHODS
Cytogenetic analysis was performed in 56 couples with history of recurrent abortions from 1995 to 1999. The use of high resolution banding technique and fluorescent in situ hybridization (FISH) in the chromosomal analysis has made the precise evaluation of chromosome aberrations.
RESULTS
Among 56 couples, 42 patients had reciprocal translocation and 14 had Robertsonian translocation. Chromosomal aberrations were more frequent in women (36 cases) than in men (20 cases). Prenatal cytogenetic analyses were carried out in 14 subsequent pregnancies for carrier couples with balanced translocation. The fetal karyotypes showed that 5 cases (35.7%) was normal, 8 (57.1%) were balanced translocation, and 1 (7.1%) was unbalanced translocations. And cytogenetic analyses were done on 15 subsequent chorionic villi samples of abortuses for carrier couples with balanced translocations. Fourteen of fifteen abortuses (93.3%) were abnormal karyotype.
CONCLUSIONS
Although the incidence of chromosomal imbalance in the fetuses was relatively low in prenatal cytogenetic analysis, individuals with balanced translocations are predisposed to giving birth to malformed offsprings with chromosomal imbalance (partial trisomy or monosomy). Therefore we recommend preimplantation genetic diagnosis (PGD) for recurrent abortions with balanced translocation and preventing the birth of offspring with chromosomal abnormalities.