Gestational Subclinical Hypothyroidism Clinical Research

Part One The clinical characters of subclinical hypothyroidism women before conception and during pregnancyObjective To investigate the clinical characters of subclinical hypothyroidism (SCH) women before conception and during pregnancy.Methods Women with TSH>2.5mlu/1(diagnosed before pregnancy or before28weeks of gestation) were recruited. Thyroid functions and thyroid auto-antibodies (TPOAb and TGAb) were detected. One hundred and ninety-one pregnant women with SCH were selected. To investigate the clinical characters of subclinical hypothyroidism.Results The prevalence of thyroid auto-antibody positive (TPOAb and/or TGAb) was41.88%. There was a significantly difference in the TSH levels between thyroid autoantibody positive subjects and negative subjects (5.98±3.10mlu/1vs5.02±1.87mlu/1, t=2.663,P=0.008). There was a significantly difference in the TT4levels between thyroid autoantibody positive groups and negative groups (108.24±26.49nmol/1vs118.18±23.82nmol/1,t=-2.714, P=0.007). There were not significantly difference in the FT4, TT3, FT3levels between the two groups.There was a significantly difference in the incidence of thyroid autoantibody positive between the goiter subjects and the non-goiter subjects (57.5%vs30.63%, x2=12.708, P<0.001).Conclusion The levels of TSH and TT4are associated with the status of thyroid auto-antibodies in the women with SCH (diagnosed before pregnancy or in the first trimester and second trimester). The status of thyroid auto-antibodies are possible associated with the severity of SCH. The prevalence of thyroid autoantibody positive is higher in goiter women with SCH (diagnosed before pregnancy or in the first trimester and second trimester). Part Two Study on the levothyroxine treatment doses and related factors in pregnant women with subclinical hypothyroidismObjective To study the levothyroxine treatment doses and related factors in pregnant women with subclinical hypothyroidism (SCH).Methods Fifty-six pregnant women with SCH (diagnosed before12weeks of gestation) were recruited and divided into two groups according to the baseline TSH levels, SCH group1(2.5mIu/1<TSH<5.0mlu/1.24cases) and SCH group2(TSH>5.0mIu/1,32cases). Thyroid autoantibodies (TPOAb and TGAb) were detected. All the subjects were treated with levothyroxine and the doses were adjusted according to the TSH level. The therapeutic targets were to keep the TSH levels under control--0.3to2.5mlu/1for the first trimester and0.3to3.0mlu/1for the second and third trimester.Results There is a positive correlation between the levothyroxine doses and baseline TSH levels (r=0.533, P<0.01) in pregnant women with SCH. There is a significantly difference in the levothyroxine doses between SCH group1and SCH group2(0.583±0.341ug/kg vs0.961±0.405μg/kg, t=-3.695, P<0.01). The levothyroxine doses of SCH group2were64.84%higher than group1.There is a significantly difference in the levothyroxine doses between thyroid autoantibody negative and positive subjects (0.680±0.370ug/kg vs0.918±0.440ug/kg, t=-2.197, P=0.032). The levothyroxine doses of thyroid autoantibody positive subjects were35%higher than negative subjects. In addition, There is a significantly difference in the levothyroxine doses between thyroid autoantibody negative and positive subjects (0.42±0.192μg/kg vs0.720±0.385μg/kg, r=-2.331, P=0.029) in SCH group1. While in SCH group2, the difference dose not reach a statistical significance.Conclusion The baseline TSH levels and status of thyroid autoantibody may have an effect on the levothyroxine treatment doses in pregnant women with SCH. Part Three Investigation of thyroid function tests in subclinical hypothyroid women treated with levothyroxine during pregnancyObjective To investigate the value of TSH, TT4and FT4in subclinical hypothyroid (SCH) women treated with levothyroxine (L-T4) during pregnancy.Methods Eighty women with SCH diagnosed before pregnancy or before20weeks of gestation were recruited and treated with L-T4. Serum concentrations of TSH, TT4and FT4were measured by electrochemiluminescence (ECL) immunoassays. L-T4doses were adjusted according to the TSH levels. The therapeutic targets were to control serum TSH concentrations between0.1to2.5mlu/l for the first trimester,0.2to3.0mlu/l for the second trimester and0.3to3.0mlu/l for the third trimester.Results Compared with baseline, serum TSH concentrations were significantly decreased (4.80±1.41mIu/l vs2.01±0.70mlu/1,t=14.986, P=0.000), serum TT4concentrations were significantly increased (140.19±23.86nmol/1vs120.72±22.38nmol/1, t=-6.305, P=0.000) after L-T4treatment. The difference of serum FT4concentrations does not reach a statistical significance.When serum TSH concentrations reach the therapeutic targets, serum TT4concentrations in46.25%of the patients (37/80) were within the upper1/3of the nonpregnant normal reference range, while serum FT4concentrations in only16.25%of the patients (13/80) were within the upper1/3of the nonpregnant normal reference range.Conclusion To evaluate thyroid function with ECL immunoassays, serum TT4concentration has a closer correlation with TSH and may be superior to FT4during pregnancy. Part Four Clinical observation of5euthyroid women with positive anti-thyroid antibodies before pregnancyThyroid Autoantibodies (TGAb. TPOAb) are important markers of autoimmune thyroid dysfunction. Five euthyroid women with positive anti-thyroid antibodies before pregnancy were recruited in the report for observing the level of TGAb. TPOAb, alteration of thyroid function, the incidence of postpartum thyroiditis and poor gestational outcomes during gestation and Postpartum.