Background Thyroid disease is the second most commonly affected disease in childbearing women, after diabetes, and thyroid autoimmunity in pregnancy has been connected with adverse pregnancy outcomes such as miscarriage, recurrent miscarriage, preterm birth, and low intelligence.
 Objectives The study seeks to determine whether there is a significant correlation between anti-thyroid peroxidase antibodies and unexplained recurrent miscarriages.
 Patients and MethodsA Case-control study was conducted on 124 participants, 62 women who had experienced unexplained recurrent miscarriage and 62 healthy women without a history of miscarriage, from 11.9.2021 until 10.6.2022 in the outpatient and emergency department of Sulaimani Maternity Teaching Hospital and some private clinics in Sulaimani City/Kurdistan Region /Iraq, and screening for TSH and anti–thyroid peroxidase antibody are done for both groups.
 ResultsThe prevalence of positive anti-thyroid peroxidase antibody in women with recurrent miscarriage was 19.4 %, while in women without miscarriage was 6.5% (which is considerably higher in cases than in women without recurrent miscarriage with a p-value of 0.03 and an odd ratio of 3.48 (95% CI; 1.06-11.48).
 ConclusionThere is a statistically significant relationship between anti-thyroid peroxidase antibodies and recurrent miscarriage. We recommend screening for TSH and thyroid antibodies for women with recurrent miscarriages and further studies on the effect of levothyroxine therapy for euthyroid women with antibody positive.