Do chromosomal abnormalities reappear in subsequent pregnancies and how often?

Abstract

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.