Interleukin-10 Promoter-1082A/G Polymorphism and Idiopathic Recurrent Miscarriage Risk

Inclusion Criteria: 1. women with more than three consecutive unexplained pregnancy losses before the 20th week; 2. Chinese Han Population; 3. Patients who signed informed consent. Exclusion Criteria: 1. Patients who had other high-risk factors which might relate with recurrent miscarriage, including: (1) Parental karyotype abnormalities: significant rearrangements (e.g. balanced translocations and mosaics) were considered abnormal. If either the patient (or her partner) had an abnormal karyotype, it was considered a parental karyotypic abnormality; (2) Genital tract abnormalities: Any congenital anatomical deformation of the genital tract was considered abnormal; intrauterine adhesions, endometriosis and hydrosalpinx were also considered abnormal; (3) alloimmune disorder; (4) Endocrine abnormalities: prolactin (PRL) level \>25 ng/ml, testosterone level \>2.6 nmol/L, thyroid-stimulating hormone level \<0.30 mU/L or \>4.5 mU/L, free thyroxine (FT4) level \<8.36 nmol/L or \>29.6 nmol/L and free triiodothyronine (FT3) level \<1.84 nmol/L or \>7.39 nmol/L. Glucose level \> 126mg/dl; (5) Autoimmune disorders: Any positive results of Anti-cardiolipin antibodies (ACA-IgG/IgM/IgA), anti-nuclear antibodies (ANA-IgG), anti-endometrium antibodies (AEA-IgM), anti-ovary antibodies (AOA-IgM), anti-sperm antibodies (ASA-IgM), antithyroidin(TG-Ab), anti-thyroid peroxidase antibody(TPO-Ab) and/or anti-chorionic gonadotropin hormone antibody; (6) Hypercoagulation state: D-dimer levels \>260 ng/ml, fibrin degradation products (FDP) levels \>5 mg/L or anti-beta 2-glycoprotein I (anti-beta 2-GP1) levels \>15 U/ml; (7) Negative RH blood groups; (8) Abnormal semen routine results of patients husband. 2. Patients with serious diseases; 3. Patients with administration of contraceptive pills; 4. Patients participated in other randomized clinical research; 5. Patients could not be followed-up of a long time or had poor compliance; 6. Patients with other factors that would affect the study result.