Trimester-specific Reference Intervals Of Thyroid Hormones For Normal Pregnancy And Screening For Thyroid Diseases In Chengdu

Background: Since the level of thyroid hormones in pregnant women iscompletely different from the non pregnant women, there are significantdifferences between different pregnancy. At the same time, because thedetection method, sample size, study of the race, the iodine nutrition conditionand other factors, led to the difference between the normal reference rangewas established in different countries and regions of the thyroid hormone.Therefore, the establishment of the region’s pregnancy thyroid hormonenormal reference range is helpful to reduce the misdiagnosis and misseddiagnosis of thyroid disease rate, especially hypothyroidism and subclinicalhypothyroidism missed diagnosis rate, is very necessary for clinical diagnosis,treatment and monitoring of pregnant women with thyroid disease.Objective:1, establish Chengdu area of pregnant women in early pregnancy(T1),the second trimester (T2), late pregnancy (T3) in normal thyroid specificserum marker value range.2, screening the prevalence of thyroid disease, the positive rate ofTPOAb, and the positive rate of TGAb, of the pregnant women.Research object:From January to July2013in Sichuan Provincial People’s HospitalDepartment of gynaecology and obstetrics cards room pregnant women in1374cases, deducting of62cases of unconfirmed gestational age or missing data of TSH、FT4detection, so only1312effective cases, as the group A.Based on the group A as research object, screening according to theNACB (National academy of clinical biochemistry) recommended conditionsand the inclusion criteria, pregnant women serum in1038cases were enrolledas the group B.Research methods:According to gestational age group B pregnant women were divided intoearly pregnancy T1, metaphase T2, late T3, a retrospective cross-sectionalsurvey method, using the median and the95%confidence interval statisticalmethods to establish pregnancy specific serum TSH, TT3, FT3, TT4, FT4normal reference range, and related analysis.Establishment of normal reference value range in the B group as thebasis, a retrospective cross-sectional survey method, using percentilestatistical method that A group thyroid disease prevalence rate of pregnancywomen (hypothyroidism, subclinical hypothyroidism, low T4level) and thepositive rate of TPOAb, TGAb.Results:1, pregnancy in the three serum TSH95%confidence interval: T10.01-4.94mIU/L, T20.10-4.61mIU/L, T30.38-4.47mIU/L. Serum TSH leveldecreased in T1phase, and reached the lowest values in G8-G12, a gradualincrease in the T2phase, T3phase is stable.2, pregnancy in the three serum TT395%confidence interval: T11.52-3.13nmol/L, T21.57-3.34nmol/L, T31.53-2.92nmol/L.3, pregnancy in the three serum FT395%confidence interval: T13.86-6.47pmol/L, T23.62-6.34pmol/L, T3:3.39-5.84pmol/L.4, pregnancy in the three serum TT495%confidence interval: T1 73.82-173.16nmol/L, T280.13-170.97nmol/L, T368.65-163.76nmol/L.5, pregnancy in the three serum FT495%confidence interval: T111.42-20.87pmol/L, T210.80-17.53pmol/L, T38.83-14.72pmol/L.6, in the T1, T2, T3and the throughout pregnancy serum, TSH and TT3correlation is not obvious, TSH was negatively correlated with FT3, TT4, FT4,TT3and FT3, TT4and FT4was significant positive correlation.7, the positive rate of TPOAb was12.58%, the positive rate of TGAbwas6.94%, the total prevalence rate was0.46%, hypothyroidism, subclinicalhypothyroidism the total prevalence rate was2.36%, the total prevalence ratewas0.91%, the low T4in the total prevalence rate was2.29%.8, regardless of the TSH level of pregnant women is normal or not, theremight be TPOAb positive cases.9, TPOAb positive pregnant women with hypothyroidism prevalencerate was2.42%, TPOAb negative pregnant women with hypothyroidismprevalence rate was0.17%, TPOAb positive pregnant women with subclinicalhypothyroidism prevalence rate was4.24%, TPOAb negative pregnantwomen with subclinical hypothyroidism prevalence rate was2.09%.Conclusion:1, by using the method of cross in this study, through the research ofpregnancy were collected and statistically analyzed serum samples fromwomen to Chengdu area, to establish the normal reference as early as inserum TSH, three TT3, FT3, TT4, FT4range, while the positive rate ofTPOAb, TGAb and hypothyroidism, subclinical hypothyroidism, low T4levelin rate.2, pregnancy thyroid function index has obvious fluctuation, the changetrend of TSH was decreased in early pregnancy, pregnancy8-12weeks fell to the lowest level, the mid and late pregnancy level gradually increased; theserum TT4level increased rapidly throughout the pregnancy, was slightlydecreased after, the stable change trend; serum FT4the first level is increasedslightly, slightly decreased after changing trend, and finally tends to be stable.3, the reference range of pregnancy specific serum thyroid index, canincrease the detection rate of thyroid disease in pregnancy women, to decreasethe rate of missed diagnosis and misdiagnosis rate, especially hypothyroidismand subclinical hypothyroidism missed diagnosis rate.4, pregnant women in case in TPOAb positive sera would be quitepossible to have autoimmune thyroid disease. The study concluded thatTPOAb positive pregnant women with hypothyroidism, subclinicalhypothyroidism prevalence rate is respectively14times,2times of TPOAbnegative pregnant women. close monitoring should be conducted for thethyroid function.