Association of Thyroid-stimulating Immunoglobulin in Early Pregnancy with Adverse Obstetric Outcomes: A Retrospective...

The prevalence of TSI positivity in pregnant women and its association with pregnancy complications remain unclear.

This study evaluated 3090 pregnant women with stored serum samples during early pregnancy at Peking University First Hospital from October 2017 to August 2018. The risks of maternal and fetal adverse outcomes were compared across three groups: group A (TSI < 0.1 IU/L), group B (0.1≤ TSI < 0.55 IU/L), and group C (TSI ≥ 0.55 IU/L), using logistic regression models.

The positivity rate of TSI (≥0.55 IU/L) was 1.33%, whereas 96.31% of women had TSI levels below the lower detection limit (<0.1 IU/L) in general pregnant women. 0.36% of women had TSI levels higher than three times the upper limit of the reference range. In the first trimester of pregnancy, thyrotoxicosis was most common in group C (12.20%), whereas the majority of women in group A were euthyroid (83.12%). Compared with group A, women in group B had an increased risk of fetal loss (OR 2.30, 95% CI: 1.17∼4.52), preterm birth (OR 2.29, 95% CI: 1.002∼5.22) and maternal composite outcomes (OR 1.62, 95% CI: 1.002∼2.63) . Women in group C had higher odds of neonatal hospitalization (OR 2.09, 95% CI 0.90∼4.88) than group A, but this increase did not each statistical significance. No significant differences were observed in other pregnancy outcomes across the three groups.

TSI might be associated with thyroid autoimmunity and an increased risk of adverse obstetric outcomes. However, universal screening is not warranted during pregnancy.