Anti-TPO-Negative Subclinical Hypothyroidism in the First Trimester and Its Influences on Obstetric and Neonatal Outcomes

Abstract

Background

The aim of this study was to assess the relationship between maternal anti-thyroid peroxidase (anti-TPO)-negative subclinical hypothyroidism (SCH) in the first trimester with complications of pregnancy and neonatal outcomes.

Methods

The study was done at a maternity and children's research training hospital. First-trimester thyroid function tests (TFTs) (free thyroxine (FT4), thyroid stimulating hormone (TSH), anti-TPO) were checked for mothers who gave birth at the center, and their newborns were accepted for the study. Based on the results of the TFTs, two groups were formed, the normal thyroid function (euthyroid) and SCH groups. The neonatal and maternal outcomes were noted.

Results

This study included 150 mothers, of whom 110 (73.3%) had normal thyroid function and 40 (26.7%) had anti-TPO-negative subclinical hypothyroidism (SCH). Based on thyroid function tests (TSH: 0.1–4.0 mIU/L, FT4: 0.7–1.8 ng/dL), significant differences in pregnancy complications wereobserved, with higher rates of placental abruption, preeclampsia, and postpartum hemorrhage in the SCH group (p<0.001). Neonatal outcomes in the SCH group showed significantly higher rates of small for gestational age (SGA) (52.5%), NICU admission (77.5%), low Apgar score (52.5%), and transient tachypnea of the newborn (TTN) (67.5%) (all p<0.001). Logistic regression analysis identified SCH as a significant risk factor for TTN (OR=7.24; 95% CI: 3–17; p<0.001), while no significant associations were found with gestational age (p=0.194) or maternal age (p=0.600).

Conclusion

Anti-TPO-negative SCH in pregnancy has undesirable effects, not only during pregnancy but also in siblings, and surprisingly, it may be a risk factor for TTN.

Keywords

Maternal thyroid function - subclinical hypothyroidism - prenatal and neonatal outcomes

Publikationsverlauf

Eingereicht: 01. Januar 2025

Angenommen nach Revision: 13. März 2025

Artikel online veröffentlicht:
04. April 2025

• References

• 1 Alexander EK, Pearce EN, Brent GA. et al. 2017 guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid 2017; 27: 315-389
• 2 Korevaar TI, Peeters RP, Medici M. et al. Thyroid function and pregnancy outcomes: a systematic review and meta-analysis. Lancet Diabetes Endocrinol 2017; 5: 505-515
• 3 Pop VJ, de Nijs R, van Baar A. et al. Hypothyroidism in pregnancy: consequences for maternal and neonatal health. J Clin Endocrinol Metab 2016; 101: 2434-2442
• 4 McGrath SA, Simpson A, Moore R. et al. Thyroid disorders in pregnancy: a review of literature. J Thyroid Res 2020; 2020: 8170241
• 5 Vaidya B, Anthony L, Glenn L. et al. Autoimmune thyroid disease in pregnancy: a clinical overview. Thyroid 2018; 28: 10-18
• 6 Lazarus JH, Smyth P, Bates P. et al. The importance of antibody status in thyroid disorders during pregnancy. Best Pract Res Clin Endocrinol Metab 2012; 26: 703-718
• 7 Wang L, Li M, Zhou L. et al. Subclinical hypothyroidism and pregnancy outcomes. JAMA 2021; 325: 455-462
• 8 Davies M, Scott J, Thomas C. et al. Subclinical hypothyroidism and neurodevelopmental delays in offspring. Endocrinology 2019; 160: 2277-2286.
• 9 Vanderpump MP, Pearce SH, Lazarus J. et al. Thyroid disease in pregnancy. Endocrine Rev 2020; 41: 557-570
• 10 American Thyroid Association. Guidelines for the diagnosis and management of thyroid disease in pregnancy. 2017;
• 11 European Thyroid Association. Thyroid disease and pregnancy: clinical guidelines. 2014;
• 12 American College of Obstetricians and Gynecologists. Guidelines for the management of thyroid disorders in pregnancy. 2020;
• 13 McEwen L, Johnson M, Taylor S. et al. The role of thyroid hormones in pregnancy. Reprod Sci 2020; 27: 1429-1437
• 14 Chiarelli F, Vitale G, Torselli G. et al. Subclinical hypothyroidism in pregnancy. J Obstet Gynecol 2019; 39: 345-353.
• 15 Chinese Medical Association. Management of thyroid disorders during pregnancy. 2019;
• 16 American Thyroid Association. Clinical guidelines for hypothyroidism in pregnancy. 2017;
• 17 Figueiredo J, Silva A, Nascimento P. et al. Thyroid hormone levels and vascular function in pregnancy. J Hypertens 2021; 39: 730-737
• 18 Andoh T, Kurokawa T, Ueno S. et al. Thyroid hormones and respiratory control in the newborn. J Endocrinol Metab 2018; 103: 3598-3604
• 19 Wang H, Zhang J, Li Y. et al. Impact of fetal thyroid hormone levels on metabolic outcomes. J Clin Endocrinol Metab 2022; 107: 1472-1479
• 20 Benhadi N, van Eeden L, van Dijk J. et al. Thyroid function and pregnancy complications. Thyroid 2020; 30: 1644-1653
• 21 Pearce EN, Bristol L, Larsen PR. et al. Hypothyroidism and pregnancy: diagnostic and therapeutic guidelines. Endocrinology 2017; 158: 2-10
• 22 Endocrine Society. Management of subclinical hypothyroidism in pregnancy. 2019;
• 23 Smith J, Johnson A. et al. Impact of thyroid hormone treatment on maternal pregnancy outcomes in women with subclinical hypothyroidism without TPOAb: a retrospective cross-sectional study. Thyroid Res 2024; 20: 1-10
• 24 Nguyen T, Brown E. et al. The effect of levothyroxine treatment on neonatal and maternal health in subclinical hypothyroidism: a multi-center study. J Obstet Gynecol 2024; 45: 113-120
• 25 Janson R, Bosman J, Meijer F. et al. Retrospective studies and limitations in pregnancy research. Thyroid Res 2020; 13: 79-83
• 26 Brown D, McDonald S, Nelson L. et al. The impact of levothyroxine in pregnancy outcomes: a systematic review. Endocrine 2021; 72: 458-468
• 27 Reed S, Nelson R, Evans M. et al. Thyroid disease in pregnancy: evidence and guidelines. Obstet Gynecol 2022; 139: 575-583