ABSTRACT
Congenital and acquired thrombophilia are associated with an increased risk of pregnancy-associated
venous thrombosis and fetal loss. Two hundred eighty-nine patients with a history
of recurrent spontaneous abortion were subjected to screening examinations for the
etiology of these abortions. Endocrine abnormality (28.0%), uterine abnormality (10.4%),
autoimmune diseases (1.4%), antiphospholipid antibody syndrome (4.5%), and balanced
type chromosome translocation (4.2%) were found as underlying causes of recurrent
abortions, and the remaining 55.0% of the 289 patients were classified as having an
unexplained etiology. Congenital thrombophilia such as protein C (PC) deficiency,
protein S (PS) deficiency, antithrombin deficiency, and factor V Leiden mutation was
not frequently detected; only one patient had PS deficiency. A reduced factor XII
activity was found at a frequency of 4.2%. The frequency of methylene tetrahydrofolate
reductase gene C677T mutation in recurrent aborters (0.38) was the same as that found
in a fertile control group. Although the prevalence of anti-β2-glycoprotein I antibody
(aβ2-GPI) syndrome was very low (1.7%), patients with a high titer of immunoglobulin
G (IgG) class aβ2-GPI, despite anticoagulation therapy, experienced severe fetomaternal
complications in subsequent pregnancies. The rate (13.8%) of positive tests for serum
IgA class aβ2-GPI in patients with unexplained etiology was higher than that in the
controls (0%) (P < .05). We conclude that congenital thrombophilia is rare in Japanese patients who
had experienced consecutive spontaneous abortions.
KEYWORD
Thrombophilia - factor V Leiden mutation - methylene tetrahydrofolate reductase -
antiphospholipid antibody - abortion