The relationship between thyroid autoantibody positivity and abnormal pregnancy outcomes and miscarriage in euthyroid patients

Introduction
The aim of this study is to determine the relationship between autoantibodies against TPO (TPOAb) and thyroid receptor antibody (TRAb) autoantibody positivity and abnormal pregnancy outcomes and miscarriage in euthyroid pregnant women.

Material and methods
This study is a retrospective case-control study conducted by examining the data of 16,876 women who applied to Adıyaman Training and Research Hospital for regular obstetric examination between December 2017 and March 2020. Analyses were performed to compare the risks of gestational diabetes mellitus (GDM), preeclampsia, placenta previa, placenta abruption, foetal growth restriction (FGR), foetal distress, stillbirth, preterm birth, and miscarriage. P < 0.05 was considered statistically significant.

Results
In the group with TPO +/TRAb–, placenta previa risk (odds ratio (OR) = 2.26, 1.61–3.17, p < 0.001), placenta abruption risk (OR = 4.24, 2.14–8.41, p < 0.001), FGR risk (OR = 1.28, 1.11–1.48, p < 0.001), and miscarriage risk (OR = 1.63, 1.38–1.92, p < 0.001) increased. In the group with TPO–/TRAb+, risk of preeclampsia (OR = 2.58, 2.08–3.20, p < 0.001), risk of placenta previa (OR = 2.40, 1.51–3.80, p < 0.001), and risk of miscarriage (OR = 1.29, 1.01–1.66, p = 0.004) increased. In the group with TPO+/TRAb+, GDM risk (OR = 1.86, 1.44–2.41, p < 0.001), placenta previa risk (OR = 4.76, 3.30–6.86, p < 0.001), and miscarriage risk (OR = 1.67, 1.31–2.11, p < 0.001) increased.

Conclusions
Thyroid autoantibody positivity is associated with negative perinatal outcomes such as miscarriage, placenta previa, GDM, and preeclampsia, regardless of thyroid hormone levels. Thyroid autoantibody detection in early visits of pregnant women should be a warning for the clinician.