Impact of thyroid autoantibodies on pregnancy: A prospective cohort study

TL;DR

This study shows that thyroid autoantibodies in pregnant women are linked to higher risks of complications like high blood pressure and lower birth weight, even if thyroid function is normal.

Contribution

The study demonstrates that thyroid autoantibodies are independently associated with adverse pregnancy outcomes, even in euthyroid women.

Findings

Thyroid autoantibody-positive women had higher risks of pregnancy-induced hypertension, gestational diabetes, and neonatal ICU admission.

Neonates of antibody-positive mothers had lower birth weight and higher risk of being small-for-gestational age.

The associations remained significant after adjusting for maternal age, BMI, parity, and TSH levels.

Abstract

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.