Ultrasonographic Evaluation of Thyroid Gland Volume and Nodularity in Pregnant versus Non Pregnant Females: A Cross-sectional Study

Introduction: Continuous stimulation of thyroid gland occurs during pregnancy in order to meet the demands of growing foetus. This might result in variations in thyroid gland morphology which may be misdiagnosed if not assessed accurately. Ultrasonography can measure these variations during pregnancy in the form of change in volume, echotexture, nodularity etc.

Aim: To compare the thyroid volume and nodules using ultrasound, amongst different trimesters of pregnancy and with non pregnant women of similar age and find the correlation with different factors.

Materials and Methods: A time-bound, hospital-based, cross-sectional observational study was done in the Department of Radiodiagnosis, Maharaja Yeshwantrao (MY) Hospital, Indore, Madhya Pradesh, India, from April 2021 to August 2022 on 240 patients. All subjects were divided into groups of 60 women each, which included non pregnant women in group 1 and pregnant women during each trimester in rest three groups, as group 2, 3 and 4, respectively. Thyroid volume and nodules were measured in each group. The descriptive data was calculated using mean and standard deviation and then compared using Analysis of Variance (ANOVA) test. Linear regression analysis was also used to assess the correlation.

Results: Most 125 (52%) of the women belonged to the younger age group i.e., 21-25 years. Majority i.e., 114 (47.5%) of pregnant women were primigravida. Mean total thyroid volume in non pregnant group, 1st trimester group, 2nd trimester group and in 3rd trimester group were 5.44±0.82 mL, 5.85±0.64 mL, 6.25±0.67 mL and 7.24±1.16 mL, respectively, with up to 24% increase of thyroid volume during the course of pregnancy (p-value=0.001). Thyroid nodule incidence was 12.2% in pregnant women and 5% in non pregnant women.

Conclusion: With pregnancy, there is an increase in thyroid gland size along with a small increase in thyroid nodularity. Also, the interplay of a few factors such as Body Mass Index (BMI), parity, age etc., was noted.