Studies On The Relationship Between Antithyroid Antibodies And Recurrent Spontaneous Abortion

The recurrent spontaneous abortion(RSA) refers to the occurrence of two or more consecutive spontaneous abortions. RSA is a common gestational complication with an incidence rate of 1-2%. The etiological factors involved in RSA include genetics, endocrine, anatomy, infection and other environmental factors.50-60% of RSA are related to immunological causes .which are divided into alloimmune and autoimmune factors. Autoimmune factors account for 1/3 of immune-related RSA, this type of RSA is typical with existence of autoantibodies. The studies on the relationship between the antithyroid antibodies(ATA) and RSA were carried out lately. The purpose of this study is to provide experimental evidences for clinical diagnosis and treatment of RSA.In our study, serum levels of ATA were determined by ELISA in 80patients with the histories of unexplained RSA(study group) and 40 normal healthy women(control group) to investigate the relationship between RSA and ATA.Among antithyroid antibodies, two subtypes , antithyroid peroxidase antibodies(a-TPO) and antithyroglobulin antibodies contribute much to RSA. Our research detected the serum levels of the two subtypes in the RSA patients and control group. So far, in relevant studies, the positive rates of ATA range from 22. 5% to 39% among RSA patients. In our study, the women with RSA show a higher incidence of ATA(33.8%) compared with normal controls(10.0%),which is statistically significant (P<0. 01) . This result indicates that there is important correlation between ATA and RSA.The relationship between ATA and durations of pregnancy: the incidence rate of ATA is 38.0% in the first trimester, while the incidence is 26.7% in late abortions. The positive rate of ATA in early abortions is statistically significant compared with normal controls, while the incidence of ATA is not significantly high in late abortions, and no difference between two groups. This result shows that ATA are associated with early abortions.As far as the relationship between ATA and times of abortions is concerned, our results show positive rate of ATA in patients with 2 times abortions is 33.3%, lower than that(34. 4%) in 3 times or more abortions, both groups have significant higher rates than control group. But there is no difference between two groups. This outcome indicates ATA have no apparent relation with times of abortions.Our study also shows relations of the subtypes of ATA and pregnancy loss: The incidence of a-TPO with the rate of 25.0% is higher in RSA groups than normal controls, having statistic significance. While the positive rate of a-TG is 18.8%, significantly higher in study group than in controls. These results indicate both a-TPO and a-TG have close relation with RSA occurrence.The study on ATA and RSA is rare in our country. Our study is advanced in our country to illustrate the relation between ATA andRSA. Nowadays ATA is considered to be a marker of abnormal immune condition, and some studies showed that women with RSA had ATA but did not have increased antiphospholipid antibodies. So ATA also can be an independent marker of the risk of pregnancy loss. It is of high significance to determine serum ATA level for diagnosis and timely treatment of RSA.