Euthyroid With Thyroid Antibodies

The goal of this clinical trial is to learn if combined treatment of levothyroxine and hydroxychloroquine would improve the live birth of euthyroid women with thyroid peroxidase antibodies and unexplained recurrent pregnancy loss. Researchers will compare combined treatment of levothyroxine and hydroxychloroquine to a treatment of levothyroxine alone to see if combined treatment works to improve live birth of euthyroid participants with thyroid peroxidase antibodies and unexplained recurrent pregnancy loss. Participants will: * Receive combined treatment of levothyroxine and hydroxychloroquine or treatment of levothyroxine alone every day at least 8 weeks before pregnancy, and continue their treatment till the end of pregnancy. * Visit the clinic 4 weeks and 8 weeks after their treatments, and every 12 weeks before they get pregnant for checkups and tests. During their pregnancy, they will visit the clinic before gestation of 12 weeks, and will be followed up with phone call in the second trimester and after parturition.