Chromosomal Anomalies in Abnormal Human Pregnancies

Abstract

Objective: The aim of this study was to describe the cytogenetic observations on abnormal human pregnancies (anembryonic pregnancy, early fetal loss, and hydatidiform moles), and to detect the most frequent or typical chromosomal aberration for anembryonic pregnancy and early fetal loss. Study Design: Abnormal pregnancies were divided into three clinical and morphological groups: (a) anembryonic pregnancy; (b) early fetal loss, and (c) hydatidiform mole. Of the 119 karyotyped tissue samples, 42 (35%) were from anembryonic pregnancies, 64 (54%) from early fetal losses, and 13 (11%) were from hydatidiform moles (6 complete and 7 partial moles). Long-term cultures of chorionic villi and GTG-banding techniques were used for chromosome analysis. Results and Conclusion: The overall frequency of chromosome anomalies among the 119 karyotyped spontaneous abortions was found to be 37.8%. Trisomy (double trisomy included) accounted for 35.6% of all aberrations, followed by polyploidy (33.3%), mosaicism (11.1%), tructural abnormalities (4.4%), and monosomy X (2.2%). Although the difference was not statistically significant, single trisomy was the predominant chromosome abnormality found in anembryonic pregnancies (64.3%) while in cases of early fetal loss, trisomy (double trisomy included) (38.9%) and triploidy (27.8%) were quite frequently present. The frequency of triploidy among all chromosomal abnormalities was 28.9%, and 53.8% of them were found in partial hydatidiform mole. The rest of them were almost exclusively found in early fetal losses. Complete hydatidiform moles (androgenetic in origin) were present in 13.3% of all aberrations, of which 83.3% had a 46,XX, and the rest of them had a 46,XY karyotype.

Association between different morphological types and abnormal karyotypes in early pregnancy loss

“…These results are at variance with previous reports by other authors showing no association between morphological features and karyotypes in EPL14–16, 26. However, the total percentage and distribution of the different chromosomal abnormalities as well as the male to female sex ratio found in the present study did not differ significantly from those reported in previous cytogenetic studies performed on EPLs20–22, 24, 25, adding strength to our results.…”

“…However, few of these studies investigated the relationship between chromosomal abnormalities and TVS findings in EPL. Moreover, only a few ultrasound findings were taken into account, such as the presence or absence of an embryonic pole, variations from the expected crown–rump length (CRL) of the embryo‐fetus, presence of trophoblastic disease or empty sac 23–25.…”

Do specific ultrasonography features identified at the time of early pregnancy loss predict fetal chromosomal abnormality? – A systematic review and meta-analysis

“…From the 13 included studies, 2 × 2 tables for the chromosomal abnormality rate in EPL with or without ultrasound identifiable embryo could be constructed6, 7, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21; four of these studies were included for the chromosomal abnormality rate in EPL with short CRL7, 10, 14, 20; two studies for the chromosomal abnormality rate in EPL with small GS7, 10; two studies for the chromosomal abnormality rate in EPL with YS only7, 17; two studies for the chromosomal abnormality rate in EPL with symmetrical arrested growth7, 10; one study for the chromosomal abnormality rate in EPL with enlarged YS 10 Table 1 summarized the general information of the 13 included studies in the analysis.…”

Parental origin and mechanisms of formation of triploidy: a study of 25 cases

“…[1][2][3] Two distinct phenotypes are known to be associated with triploidy. A minority of foetuses presents with moderate growth retardation, proportionately sized body parts and particularly large placentas with partial hydatidiform mole (type I [4][5][6] ).…”