Evaluation of thyroid stimulating hormone and free thyroxine and their correlations with other biomarkers in sudanese pre-eclamptic cases

Introduction: Pregnancy causes stress on thyroid gland especially in areas of iodine deficiency. Women with pre-eclampsia are more likely to have slightly reduced thyroid function during the last weeks of their pregnancies. Objectives: This study was to assess changes in serum Thyroid Stimulating Hormone (TSH) and Free Thyroxine (FT4) in pre-eclamptic cases compared to second-half normal pregnant and non-pregnant Sudanese women and their correlations to other biomarkers. Methods: This was a case-control study, in Omdurman Maternity Hospital, Sudan. The pre-eclamptic cases (72) were compared to control second-half normal pregnant (96) and non-pregnant (63) Sudanese women. The groups were matched. The clinical and laboratory investigations were undertaken at St Hellier s hospital – London. TSH was measured by two-site sandwich immunoassay and Free T4 by competitive immunoassay using chemiluminescent technology. Liver and renal function tests were performed using atomic absorption spectrophotometer (SiemensAdvia2400 Chemistry System Serial No CA12420098and No a12420083). Results: There was a highly significant difference in mean of TSH in mU/L between pre-eclamptic (2.52 ± 1.15) and non-pregnant (1.36 ± 0.71) (P-value = 0.000), between pre-eclamptic (2.52 ± 1.15) and pregnant (1.53 ± 0.79) (P-value = 0.000), but no significant difference between non-pregnant (1.36 ± 0.71) and pregnant (1.53 ± 0.79) (P-value = 0.237). There was a highly significant difference in mean of FT4 in pmol/L between non- pregnant (16.11 ± 2.02) and pregnant (13.55 ± 2.09) (P-value = 0.000), between non- pregnant (16.11 ± 2.02) and pre-eclampsia (13.96 ± 2.18) (P-value = 0.000), but no significant difference between pregnant (13.55 ± 2.09) and pre-eclampsia (13.96 ± 2.18) (P-value = 0. 213). TSH, in pre-eclampsia, has significant correlations with serum uric acid (r=0.50, P=0.049), serum albumin (r = 0.28, P = 0.018) , serum Aspartate transferase (AST) (r= 0.24 P= 0.049) and urine protein (r = 0.42, P = 0.000); but had no significant correlations with blood pressure or serum Alanine Transferase (ALT) (r= 0.03, P= 0.792). FT4, in pre-eclamptic cases, had no significant correlations, except with urine creatinine (r=0.3, P=0.003). Conclusions: This study revealed that TSH was significantly increased in pre-eclamptic when compared to normal pregnant and non-pregnant women, FT4 was significantly decreased in pre-eclamptic cases when compared to non-pregnant women.