High Thyroid Peroxidase Antibody Concentrations May Indicate Active Thyroid Monitoring in Pregnant Women

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Research conducted at the Erasmus University Medical Center has shed light on the association between thyroid peroxidase antibodies (TPOAbs) and thyroid function in pregnant women. An individual participant data meta-analysis was performed on 62,634 pregnant women from 24 cohorts, with the aim of understanding the clinical relevance of TPOAb concentrations during pregnancy. The study found a positive correlation between TPOAb concentrations and thyroid stimulating hormone (TSH) levels, as well as a negative correlation with free thyroxine (FT4) concentrations. The results suggest that high normal TPOAb concentrations upon first assessment in pregnancy may warrant active follow-up.

Key Takeaways:

  • High TPOAb concentrations were associated with progressively higher mean TSH concentrations across TPOAb percentiles 89, with corresponding mean differences ranging from +0.11 SD to +1.04 SD.
  • Higher TPOAb percentiles were linked to progressively lower mean FT4 concentrations, with corresponding mean differences ranging from -0.08 SD to -0.48 SD.
  • The study found progressively higher risks of TSH 4.0 mU/L, with absolute risks of 2.4%, 4.0%, and 28.1% in cases of 80th, 89th, and 100th TPOAb percentiles, respectively.
  • The associations of TPOAbs with TSH and with FT4 were most apparent during early pregnancy.
  • The research implicated that high normal TPOAb concentrations upon first assessment in pregnancy may warrant active follow-up.

Statistics:

  • The study population comprised 62,634 pregnant women from 24 cohorts.
  • TPOAb percentiles 89 were associated with mean TSH concentrations 1.04 SD higher than TSH concentrations at TPOAb percentiles 80 (95% CI, +0.96 SD, 1.11 SD).
  • The study found a progressive increase in risks of TSH 4.0 mU/L, with absolute risks of 2.4%, 4.0%, and 28.1% in cases of 80th, 89th, and 100th TPOAb percentiles, respectively.
  • Higher TPOAb percentiles were associated with lower mean free thyroxine (FT4) concentrations, with corresponding mean differences ranging from -0.08 SD to -0.48 SD.

Sources:

  • Osinga, J. A. J., Liu, Y., Feldt-Rasmussen, U., Vrijkotte, T. G. M., Taylor, P. N., Aminorroaya, A., Ashoor, G., Bliddal, S., Chen, L.-M., Vaidya, B., Palomaki, G. E., Ghafoor, F., Lopez-Bermejo, A., Pop, V. J. M., & Sach. (2025). Interpretation of the association between thyroid peroxidase antibodies and thyroid function during pregnancy: An individual participant data meta-analysis. Journal of Autoimmunity, 157, 103491.
  • NewsRx. New Immunoglobulins Study Findings Have Been Reported by Researchers at Erasmus University Medical Center (Interpretation of the association between thyroid peroxidase antibodies and thyroid function during pregnancy: An individual participant ...). Health & Medicine Week. October 31, 2025; p 3623.