Chromosomal Analysis of Aborted Conceptuses among Anembryonic Pregnancy and Embryonic Pregnancy: Do Chromosomal Abnormalities Relate to Anembryonic Pregnancy?

Yang, Kwang Moon; Ahn, Hyun Kyong; Yoo, Keun Jai; Song, In Ok; Kim, Jin Yeong; Song, Ji Hong; Kang, Inn Soo; Jun, Jong Young; Koong, Mi Kyung; Choi, Bum Chae

Abstract

OBJECTIVES
Approximately 15-20% of all clinically recognized pregnancies result in spontaneous abortion between 8 and 12 weeks. In some early abortus only the extra-embryonic components of the conceptus survive, either as fragments of placenta or as empty gestational sac, and these have been termed 'anembryonic pregnancies'. Despite their common occurrences, the etiology of anembryonic conceptuses is poorly understood. The purpose of this study was to evaluate whether chromosomal abnormalities relate to a role in anembryonic pregnancy.
MATERIALS AND METHODS
The study, that consisted of 143 pregnancies from chromosomally normal couples that aborted in first trimester period between January 1, 1994 and December 27, 1997, had chromosomal analysis performed on the products of conception and had ultrasonographic examination prior to spontaneous abortion. The tissue was processed and analysed using standard G-banding cytogenetic techniques with long-term cultures.
RESULTS
The patient characteristics of the anembryonic pregnancy were not significantly different from those of the embryonic pregnancy. Among products of conception from embryonic pregnancies, 45% (52/115) had normal chromosomal analyses and 55% (63/115) had abnormal chromosomal analyses. Products of conception from anembryonic pregnancies resulted in 54% (15/28) of abnormal chromosome analyses and normal chromosomal analyses resulted in 46% (13/28) (p>0.05, Chi-square test). The frequency of aneuploidy and polyploidy were not different between products of conception from anembryonic pregnancy and embryonic pregnancy. Also, the gender ratio of euploid spontaneous pregnancy losses showed similar in this study.
CONCLUSION
There are no differences in frequency of abnormal karyotypes in products of conception from anembryonic pregnancies compared with miscarriage after the demonstration of fetal pole. If further studies are need for the evaluation of these etiologies, and then immuno-molecular studies in early placental tissues from anembryonic pregnancy might be helpful.