Assessment of Thyroid Function Parameters among Sudanese Pregnant Women in Different Trimesters

Background: The thyroid gland plays an important role in pregnancy outcome as well as in fetal development. The changes caused by pregnancy in the mother establish a new homeostatic equilibrium. Thyroid disorders are common during pregnancy, and adequate treatment is essential to prevent adverse maternal and fetal outcomes.

Objectives: To assess FT3, FT4 and TSH levels in pregnant Sudanese women, and to correlate their levels with the gestation age.

Materials and Methods: This analytical cross-section study was performed at Teanbool hospital obstetrics and gynaecology department in Aljazeera state- Sudan, during the period from January to October 2017. 150 samples were collected from pregnant women (50 in first, 50 in second and 50 in third trimester) as a study group. In addition to other 50 non-pregnant healthy women and age-matched as a control group. The thyroid hormones TSH, FT3 and FT4 levels in both test and control groups, were estimated by automated Cobas e 411 analyzer using electrochemiluminescence immunoassay “ECLIA”.

Results: FT3 and FT4 is significantly decreased (3.9±0.84 verses 4.54±0.65 pmoI/L, p ≤ 0.05.12.77±2.54 verses 14.80±1.95 pmoI/L, P ≤ 0.001 respectively), where as TSH is slightly increased (1.86±1.01 verses 1.99±0.95 uIU/mI, P ≥ 0.05) in the study group when compared with the reference group, FT3 is significantly correlated with FT4 (r = 0.47, p=0.001) in pregnant women. According to gestational age FT3 is significantly decreased in the three trimesters (4.1 ±0.18 verses 4.54±0.65, pmoI/L, P ≤ 0.05, 3.8±0.59 verses 4.54±0.65, pmoI/L, P ≤ 0.052, 3.7±0.42 verses 4.54±0.65, pmoI/L, p=0.02), where as FT4 is significantly decreased in the second and third trimesters (3.8±0.59 verses 14.80±1.95 pmoI/L, P ≤ 0.045, 11.28±1.68 verses 14.80±1.95 pmoI/L, p=0.000). In contrast TSH is significantly increased in the third trimester (2.08±0.58 verses 1.99±0.95 uIU/mI, P = 0.05) in the test group when compared with reference one. The study illustrated significant inverse correlation of both FT3 and FT4 with gestation age (r =-0.21, p=0.05, r =-0.39, p 0.02 respectively), whereas TSH is insignificantly correlated with gestation age in the test group (r= 0.14, p = 0.34).

Conclusion: The study revealed a significant decrease in both FT3 and FT4 levels in the pregnant women, with significant negative correlation with gestation age.