Thyroid Dysfunction and Autoimmunity in Pregnant Women with Gestational Diabetes and Pre pregnancy with Type 1 Diabetes

Abstract

ABSTRACT

Background: Diabetes mellitus and thyroid disorder have been shown to mutually influence each other and association between both conditions has long been reported. On one hand, diabetes mellitus affects thyroid function tests to variable extents, and on the other hand, thyroid hormone contributes to the regulation of carbohydrate metabolism and pancreatic function.

Objective: To determine the thyroid dysfunction and the presence of anti-thyroid peroxidase antibodies during (24-28) weeks of gestation in pregnant women with gestational diabetes mellitus and type1 diabetes

Methods:  A case control study, at Al-Yarmouk Teaching Hospital, Department of Obstetrics and Gynecology for one year from April 2013 till the end of April 2014.  Ninety five pregnant women were enrolled in this study in their 24-28 weeks of gestation, of them forty pregnant women with negative oral glucose tolerance test, fifteen pregnant women with type 1 diabetes mellitus and forty pregnant women with gestational diabetes mellitus (impaired oral glucose tolerance test). For all pregnant women, blood samples were taken for measurement of free thyroxin, thyroid stimulatory hormone and anti-thyroid peroxidase antibodies.

Results: The mean ±SD level of free thyroxin were significantly lower in pregnant women with gestational diabetes (15.0 pmol/l ±5.5) and in pregnant women with type 1 diabetes (17.7 pmol/l ±8.3) compared with control group (22.4±5.9) with P < 0.001. TSH level showed no statistically difference among the participated group with P = 218. As well the percentage of those with positive anti-thyroid peroxidase antibody have shown that (26.7%) of patient with type 1 diabetes were positive to antibodies, and this percentage was higher than that of control group (10.0%) and gestational diabetes group (15.0%), but the difference fail to reach the level of significance.

Conclusion: Thyroid dysfunctions are common during pregnancy, especially pregnancies with type 1 diabetes and those complicated with gestational diabetes. There is significantly higher incidence of hypothyroxinaemia and increase anti-thyroid peroxidase antibodies in these pregnancies than the control pregnant women.