Reference Intervals of Thyroid Hormones and Correlation of BMI with Thyroid Function in Healthy Zhuang Ethnic Pregnant Women
Table 3
The reference ranges for TSH, FT4, and FT3 according to BMI categories.
Trimesters
BMI(kg/m2)
n
TSH(mIU/L)
FT4(pmol/L)
FT3(pmol/L)
1st
<18.5
188
0.81 (0.01-3.47)
15.03 (10.85-19.72)
4.43 (3.35-5.67)
18.5-24
511
0.84 (0.02-3.27)
14.57 (10.61-19.77)
4.42 (3.54-5.66)
≥24
120
1.00 (0.05-3.26)
14.11 (9.92-19.78)
4.63 (3.50-5.73)
p value
0.021
0.085
0.004
2nd
<18.5
104
1.25 (0.02-3.42)
15.13 (11.58-19.23)
4.22 (3.00-5.62)
18.5-24
1276
1.17 (0.03-3.24)
14.47 (10.16-19.26)
4.31 (3.41-5.37)
≥24
529
1.15 (0.05-3.16)
13.73 (9.43-19.03)
4.38 (3.51-5.46)
p value
0.813
≤0.001
≤0.001
3rd#
18.5-24
202
1.44 (0.02-3.91)
13.61 (9.74-18.17)
3.84 (2.85-5.02)
24-28
277
1.66 (0.04-3.76)
13.51 (8.85-18.19)
3.94 (3.05-5.08)
≥28
117
1.60 (0.31-3.88)
12.41 (8.78-17.02)
3.97 (2.91-5.05)
p value
0.319
≤0.001
0.338
P < 0.05, Kruskal–Wallis test. #BMI was divided to normal weight, overweight, and obesity, because there were no underweight women in the third trimester.
