The Link between Body Mass Index and Maternal Thyroid Autoimmunity in Early Pregnancy

Amer, Hanan Mohammed Ali; Abdelsalam, Mona Mohammed; Algamal, Marwa; Bishay, Caroline

doi:10.21608/asmj.2025.381387.1443

The Link between Body Mass Index and Maternal Thyroid Autoimmunity in Early Pregnancy

Document Type : Original Article

Authors

¹ Department of Internal Medicine, Endocrinology and diabetes unit, Faculty of Medicine, Ain Shams University, Cairo, Egypt.

² Department of Internal Medicine, Endocrinology and diabetes unit, Faculty of Medicine, Ain Shams University, Cairo, Egypt

³ National Institute of Diabetes and Endocrinology

10.21608/asmj.2025.381387.1443

Abstract

Background: Maternal thyroid autoimmunity has hazardous effects on the mother and fetus. There are controversies regarding screening obese women during pregnancy for thyroid antibodies.
Objectives: We investigated the association between body mass index (BMI) in early pregnancy and thyroid peroxidase antibody (TPO Ab).
Patients and methods: We recruited 225 women at 4th -8th weeks of gestation. 75 women of them had normal weight (Group I), 75 were overweight (group II) and 75 had obesity (group III). We investigated Thyroid Stimulating Hormone (TSH), TPO Ab, Anti thyroglobulin antibody (Tg Ab) for all participants and compared them across the 3 groups.
Results: TPO Ab was significantly the highest in obese women and on post hoc analysis, it was significantly more in each of obese, and overweight women compared to ladies with normal BMI. On comparing the 3 groups a significant difference was found as regards the distribution of each of TPO Ab and Tg Ab positivity being the highest in the group with maternal obesity. All participants with normal BMI had normal TPO Ab and Tg Ab antibodies. In the overweight women, 8% had positive TPO Ab and 3% had positive Tg Ab. In women with obesity 16% had TPO positivity and 12% had Tg Ab positivity. TSH was significantly the highest in maternal obesity. BMI was positively correlated with TPO Ab only in obese women.
Conclusion: An association exists between maternal BMI and each of TSH, TPO Ab levels, distribution of TPO Ab and Tg Ab positivity in early pregnancy.

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