Determinants of Thyroid Autoimmunity in Pregnant Women of Rural Central India- A Cross Sectional Study

Abstract

: Background: Thyroid autoimmunity (TAI) is the most common autoimmune disorder in women of reproductive age. TAI in pregnancy is seen to rise markedly all over the world & can remain undiagnosed as it may present without thyroid dysfunction. It is seen to be associated with a number of feto-maternal disorders and may affect pregnancy outcome. The occurrence of TAI in pregnancy, in the present rural community is not known, hence this study was carried out to determine the occurrence of thyroid autoimmunity in pregnant women from rural area.

Methods: A hospital based, cross-sectional, observational study was carried out among pregnant women seeking antenatal care at Kasturba Hospital of MGIMS, Sewagram, a rural tertiary care institute in central India. Information was collected about demographic variables. Family history and other determinants. Serum TSH, Free T4, and antithyroglobulin antibody levels were in the first trimester. Thyroid status was labelled as euthyroid, overt hypothyroid, subclinical hypothyroid, overt hyperthyroid and subclinical hypothyroid and correlation was done with antibody positivity and various determinants.

Results: Among 250 pregnant women of first trimester, antithyroglobulin antibody was positive in 32 (12.8%) of which 22 (68.75%) had thyroid dysfunction in the form of hypo or hyperthyroidism, and 10 (31.25 %) were euthyroid. Of 218 with negative antibody, 24 (11%) had thyroid dysfunction and 194 (88.99%) were euthyroid with a significant difference. Though TAI was present in all age groups, the numbers increased with increasing age. Among study subjects, 9.95 % from rural compared to 28.20 % from urban residential area had TAI indicating higher occurrence in urban population. TAI was observed in all socioeconomic classes but more so in middle, lower middle and lower economic class. Positive family history was noted in 18.75 % women with positive antibody compared to 3.71 % negative women (p value 10.62, chi square 0.002). More number of pregnant women with negative antibody had an average BMI compared to positive (77.06% vs 31.25%), more positive PW were overweight compared to negative ( 37.5% vs 18.34%) and also obese ( 15.62% vs 0.91%) (Chi square – 26.67, p value – 0.00002). As BMI increased proportion of PW with positive antibody increased with a significant difference

Conclusions: Thyroid autoimmunity was seen in 12.8% pregnant women of the rural area of present study site. A substantial number of women with TAI had thyroid dysfunction and some were found to be euthyroid too. Older age, socioeconomic status, urban residence, high BMI and positive family history were risk factors for thyroid autoimmunity. Screening for thyroid antibodies in high risk pregnant women and those with thyroid dysfunction is suggested.