association of chromosome 9 heteromorphism with recurrent pregnancy loss

Background and aim: recurrent pregnancy loss (rpl), defined as three consecutive pregnancy losses before 20 weeks from the last menstrual period, is responsible for significant emotional distress to the couple desiring to conceive, and affects approximately 1% to 2% of women. heteromorphism of chromosome 9 is the most common structural chromosomal variant and often considers as a normal variation with no evidence of any phenotypic effect of the patient. nevertheless, some studies claim that the location of the heteromorphic region possibly intervenes with meiotic or mitotic events that eventually lead to the development of fertilized eggs with chromosomal abnormalities resulting in the possibility of anembryonic pregnancy (blighted ovum) or rpl.methods: in this study, we investigated 20 phenotypically normal iranian azeri couples referred to the dr. mohaddes medical genetics laboratory (dmmgl), having a history of recurrent miscarriage in the first trimester. after genetic counseling, conventional cytogenetic analysis of parents was done to delineate the role of chromosomal abnormalities through the high-resolution g-banded karyotyping technique.results: clinical, hormonal, and immunological indices of the couples disclosed normal phenotypes, and the ultrasound scans of the females showed anatomically normal uterus and ovaries. chromosomal investigations of the couples provide normal karyotypes with heteromorphism of chromosome 9 in at least one of the partners (46, xy, 9qh+ karyotypes for the males, and 46, xx, 9qh+ in the female partners).conclusion: based on the study observations and similar studies, although the heteromorphism of chromosome 9 is often considered as a normal variation, however, it seems that there is an association between the heteromorphic region of chromosome 9 and anembryonic pregnancy or rpl. thus, it looks reasonable that chromosomal analysis should be strongly suggested for couples with a history of rpl to estimate whether they have a polymorphism in chromosome 9 heteromorphic region.