Establishment Of Normal Reference Value Of Thyroid Function Index With Beckman Reagent During Pregnancy In Chengdu Area

ObjectiveTo establish a normal reference value range for specific thyroid function index with Beckman reagent for pregnant women in Chengdu.MethodsSelected pregnant women of different gestational ages who performed routine prenatal care in the First Affiliated Hospital of Chengdu Medical College from November 2016 to June 2017,according to the recommended methods of the National Academy of Clinical Biochemistry(NACB).After interrogation and physical examinations,according to the inclusion and exclusion criteria,those who did not meet the above requirements were excluded.Finally,445 pregnant women were included.According to the corresponding inclusion and exclusion criteria,120 non-pregnant women were included.Then,obtain serum free Free triidothyronine(FT3),serum free thyroxine(FT4),and serum thyroid-stimulating hormone(TSH),the limit on both sides of the indicators was calculated by the SPSS 24.0(2.5,97.5percentile),and set up the normal range of Beckman reagent.The correlation between the above indexes,the correlation between serum TSH and FT4 were analyzed.Result(1)FT3 was 4.41pmol/L~6.33pmol/L,4.17pmol/L~6.12pmol/L and3.86pmol/L~6.39pmol/L in the first,second and third trimesters respectively.FT4 was7.64pmol/L~14.63pmol/L,6.62pmol/L~13.69 pmol/L,6.62pmol/L~12.51pmol/L in the first,second and third trimesters respectively.TSH was0.21mIU/L~3.62mIU/L,0.16mIU/L~4.35mIU/L and 0.89mIU/L~4.88mIU/L in the first,second and third trimesters respectively.(2)The median FT3 in the first and second trimester were similar,and fell to the lowest level in the third trimester.The median FT4 decreased with the increase of pregnancy,it decreased to the lowest level in the third trimester and was lower than the lower limit of the reference value for normal non-pregnant women.The median TSHwas significantly lower than the reference value of normal non-pregnant women during early pregnancy and increased during the second trimester.(3)There was no statistical difference in serum TSH between the first and second trimester(P> 0.05),and there was no statistical difference in serum FT3 respectly between the first trimester,the second trimester and normal non-pregnant women(P>0.05).Serum FT3,FT4,TSH in the rest of trimesters,each trimester and normal non-pregnant women were statistically significant difference(P <0.05).(4)There was a significant correlation between TSH and FT4 in the first and second trimester(P <0.01,r =-0.2277,-0.392).There was no significant correlation between TSH and FT4 in the third trimester and normal non-pregnant women.(P>0.05).Conclusion(1)The reference value of FT3,FT4 and TSH in pregnant women with BECKMAN reagent was significantly different from that of normal non-pregnant women.TSH in the first trimester was lower than the lowest limit of reference of the normal non-pregnant women,but increased gradually with the increase of pregnancy.FT3 and FT4 gradually decreased with the increase of pregnancy,the third trimester to the lowest.(2)There was a significant correlation between TSH and FT4 in the first and second trimester.There was no significant correlation between TSH and FT4 in the third trimester and normal control group.(3)Each region and corresponding laboratory must establish their own normal reference values for specific thyroid function indicators of pregnant women to avoid missed diagnosis and misdiagnosis of gestational thyroid diseases.