Frequency of chromosomal aberrations in material from abortions

Summary Examination of fetal tissue from spontaneous miscarriages shows that 50-70% of them were caused by abnormalkaryotype. The most frequent genetic abnormalities include abnormal number of chromosomes, aberration of chromosomes structure and chromosome mosaic anomalies. Objective: the aim of the study was to find out whether there is any difference in the frequency of chromosomal aberrations in patients who miscarried for the first time comparing to patients with recurrent miscarriages. Material and methods: Examination was performed on 129 miscarriage material samples from 128 women. Fluorescent hybridization in-situ (FISH) was used for genetic examination. Results: We received 120 results in which 45 (37,5%) were abnormal. The most frequent chromosomal aberration was trisomy, followed by triploidy and monosomy of chromosome X. Among 59 samples from first miscarriage we found 25 abnormal karyotypes. In the 61 samples from the second, third and the next miscarriages we found 20 chromosomal abnormalities. Conclusions: Frequency of chromosomal aberrations in the tissue from the first miscarriage is significantly higher than in samples from second or following miscarriages, which means that genetic factors are less likely to induce recurrent miscarriages. Genetic results confirm that most chromosomal abnormalities arise de-novo

Do chromosomal abnormalities reappear in subsequent pregnancies and how often?

Abstract Objective: Genetic factors are the most common causes of spontaneous abortions. 50% to 80% of first-trimester abortions reveal chromosome abnormalities. Evidence for the recurrence of the same or another chromosome abnormality in the next pregnancy is scarce. The aim: The aim of our study was to estimate recurrence risk of abortus aneuploidy and to find out whether karyotyping of the abortus allows the prognose subsequent pregnancy outcomes. Material and methods: Paraffin-embedded chorions have undergone cytogenetic examination using FISH with chromosome-specific probes. 57 chorions from 26 women have been assessed, including chorions from two consecutive abortions from 18 women and chorions from three consecutive abortions from 5 women. Results: 38.6% of 57 specimens had chromosome aberrations. The most prevalent anomalies were 16, 21 and 18 trisomies. 23 patients had a subsequent abortion karyotyped; 15 had a normal initial karyotype and 8 had an aberrant initial karyotype. 3 out of the 8 patients had a repeated chromosome anomaly. 5 out of the 15 patients who initially miscarried an aneuploid embryo, had a subsequent miscarriage of an aneuploid embryo. Only 3 (13.04%) out of the 23 patients displayed aneuploidy in each abortus. Conclusion: 1. Chromosome aberrations can reappear in subsequent pregnancies in the same patient and may be the cause of recurrent miscarriages. 2. The value of embryo/fetal karyotyping is not decisive in prognosis of subsequent pregnancy outcome. 3. Abnormal fetal karyotype can occur regardless of other causes of pregnancy loss