| Objective: To establish the reference range of pregnancy-specific thyroid hormone levels in Western Yunnan by detecting the thyroid hormone levels in women during pregnancy in that region.Methods: A total of 423 patients who underwent standardized prenatal examination and delivery in our hospital from September 2020 to July 2022 were selected as the experimental group and divided into 3 groups according to gestational age: T1 group(0～ 13 weeks + 6 days defined as the 1st trimester),T2 group(14 ～ 27 weeks + 6 days as the 2nd trimester),and T3 group(≥ 28 weeks as the 3rd trimester).Moreover,a total of 128 non-pregnant healthy women of gestational age who underwent the prenatal examination in our hospital during the same period were selected as the control group and classified as the T0 group.4ml of fasting venous blood was taken and centrifuged at3000 rpm for 10 min to separate the serum,in which FT3,FT4 and TSH were detected.Electrochemiluminescence immunoassay was used for detection,where Roche Cobas e602 Electrochemiluminescence Analyzer and the matching kits,calibrators and quality controls supplied by Roche were used.SPSS 26.0 software was used for statistical analysis of data.The reference ranges for TSH,FT4 and FT3 were determined as median and 2.5th percentile-97.5th percentile [(P 2.5-P 97.5)],and the reference ranges for various thyroid hormones during different trimesters were established for our hospital.Results:1.In T1,T2 and T3 groups,the medians and 95% reference ranges of serum TSH were 1.68(0.26-3.84)ml U/L,2.24(0.42-4.69)ml U/L,and 2.27(0.68-4.66)ml U/L,respectively;the medians and 95% reference ranges of serum FT3 were 4.96(3.95-6.0)pmol/L,4.29(3.25-5.57)pmol/L,and 4.03(3.22-5.05)pmol/L,respectively;the medians and 95% reference ranges of serum FT4 were 16.3(13.08-20.61)pmol/L,13.6(10.77-18.07)pmol/L,and 12.7(10.65-16.4)pmol/L,respectively.2.A negative correlation was observed between serum TSH and FT4,with a positive correlation between FT3 and FT4 and no correlation between TSH and FT3 during pregnancy in Western Yunnan.3.Through comparison with the 2011 ATA guidelines and 2019 Chinese guidelines,the specific reference standards derived from this study revealed that the prevalence of hypothyrosis was 20.09%,1.65%,and 2.13%,respectively,while that of hyperthyroidism is 0.7%,0.24%,and 1.89%,respectively.Conclusions:1.In this study,the reference ranges of pregnancy-specific thyroid hormones were preliminarily established for western Yunnan.2.Serum TSH was increased with the gestational weeks over time;serum FT3 and FT4 was decreased with the gestational weeks over time.3.As various factors might result in variability of experimental data,specific reference ranges should be established for different regions to improve the diagnostic accuracy for thyroid diseases during pregnancy. |
