Recurrent spontaneous abortion (RSA) defines as two or more consecutive losses at < or =20 weeks of gestation and affects an estimated 1 of every 100 couples wishing to have children. However, it remains a poorly understood phenomenon. Recent reports observed a significant association between highly skewed X chromosome and RSA, supporting that X chromosome inactivation might be an important and previously unknown cause of RSA. X-inactivation pattern, using polymeric X-linked women with idiopathic RSA and 80 control subjects with a single successful pregnancy and no history of spontaneous abortion. The ratio of heterozygotes was 68.2% (45/66) in women with RSA and 67.5% (54/80) in control group. Among 45 informative RSA cases, only 1 (2.2%) woman showed extreme skewed X inactivation (> or =90%) and 4 (8.9%) had mild skewed inactivation (> or =85%). In 54 heterozygous control subjects, 5 (9.3%) women showed extreme skewed X inactivation and 7 (13.0%) had mild one. The frequency of skewed X inactivation between RSA patients and control group was not significantly different (p>0.05). This finding suggests that skewed x romosome be not associated with unexplained RSA patients.
Abortion, Habitual/*genetics ; Abortion, Spontaneous/*genetics ; Adult ; DNA Methylation ; *Dosage Compensation (Genetics) ; Female ; Heterozygote ; Human ; Korea ; Linkage (Genetics) ; Lymphocytes ; Pregnancy ; Support, Non-U.S. Gov't