Impact of thyroid autoantibodies on pregnancy: A prospective cohort study.

We conducted a prospective cohort study of 1,200 pregnant women recruited in early first trimester to evaluate the impact of thyroid autoantibodies (TPOAb and/or TGAb) on maternal and neonatal outcomes. Overall, 18.2% were antibody-positive. Compared with antibody-negative women, those with thyroid autoimmunity had significantly higher risks of pregnancy-induced hypertension (12.6% vs 7.9%), gestational diabetes (15.3% vs 10.2%) and neonatal intensive care unit admission (11.2% vs 6.5%). Adjusted logistic regression confirmed independent associations after controlling for maternal age, BMI, parity and TSH levels. Neonates born to antibody-positive mothers had lower mean birth weight (2980 ± 420 g vs 3125 ± 395 g, p=0.02) and higher risk of small-for-gestational age (8.7% vs 4.9%). Thus, we show that thyroid autoantibodies, even in euthyroid women, are associated with adverse pregnancy outcomes and justify closer monitoring during antenatal care.