Characteristic of Anaemia in Hypothyroid Pregnant Females: A Case-control Study

Abstract

Introduction: Anaemia is the most prevalent haematological abnormalities associated with thyroid disorders and it is often the first sign of hypothyroidism. Pregnancy is frequently associated with anaemia; most commonly iron deficiency anaemia, followed by dimorphic anaemia. Pregnancy complicated by the development of hypothyroidism could be further associated with a higher incidence of anaemia. Aim: To determine the incidence and characteristic of anaemia in pregnancy associated with hypothyroidism. Materials and Methods: This case-control study was conducted in a Medical college hospital during January 2015 to January 2016. A total of 272 pregnant women were enrolled in the study by random sampling of all pregnant females attending Out Patient Department of our hospital. Serum Thyroid Stimulating Hormone (TSH) level was used to detect thyroid function abnormalities. Complete Blood count was done. Peripheral blood smear was stained by Leishman stain and subsequently studied under microscope for morphological classification of anaemia. Anaemia was further classified according to the Haemoglobin (Hb) level into mild, moderate and severe anaemia. Unpaired t-test, Pearson’s correlation test and chi-square test have been used in the study for analysis and comparison of various parametres. p-value <0.05 considered level of significance. Results: Out of total of 272 subjects selected for the study, 207 were euthyroid and 65 were hypothyroid. Of the 65 hypothyroid subjects, 19 were in the first trimester, 25 in the second trimester and 21 were in the third trimester. The mean TSH of euthyroid group was 2.49±1.35 mIU/L and hypothyroid group was 6.27±3.6 mIU/L (p-value 0.0001). Mean Hb of Euthyroid was 10.16 g/dL, while mean Hb of hypothyroid subjects was 8.92 g/dL and this difference was significant (p<0.001). A total of 191 (70.22%) out of 272 pregnant subject were found to be anaemic. About 131 (63.28%) out of 207 of euthyroid patients were anaemic, while 92.31% of hypothyroid patients (60 out of 65) showed anaemia. A significant association was found between Hypothyroidism and anaemia (p-value <0.0001). The mean Thyroid stimulating hormone value of anaemic patients was 3.98±1.02, which is significantly higher (p<0.0001) than TSH value of 2.65±0.98 as seen in non-anaemic patients. The majority of anaemia cases in both euthyroid and hypothyroid groups were found to be of moderate severity. Dimorphic anaemia was the most common type of anaemia morphologically in both euthyroid and hypothyroid subjects. It was also the most common type of anaemia in all three trimesters. Conclusion: The incidence of anaemia was higher in the hypothyroid group compared to the euthyroid group. Thus, it is very important to study the incidence and type of anaemia in hypothyroid pregnant females, so that appropriate early nutritional and medicinal intervention can be taken so as to prevent the morbidity and mortality in these patients.