Influence Of Hypothyroidism & Subclinical Hypothyroidism On Pregnancy And Its Outcomes

Background and objective:Subclinical hypothyroidism is common in the population and especially in reproductive women.It is noticed that maternal thyroid dysfunction during pregnancy such as hypothyroidism can lead to both obstetrical complications and adverse reproductive outcomes. Not only overt,but also subclinical thyroid disorders are high risk for pregnancy. Hypothroidism is a chronic but progressive disease,without overt clinical characteristics,so thyroid function screening in high-risk women is necessary and treatment should be caught out in time.Subclinical hypothyroidism is moving with a result of overt hypothyroidism, which is related to the increased level of TSH,as well as the positive thyroid peroxidase antibody(TPOAb).Hyperthyroidism can lead to severe complications on both mother and offspring,which is only next to gestational diabetes.However the adverse effect is minor if mothers get treatment during pregnancy.The aim of this study was to monitor the change of thyroid function and antibody during the course of pregnancy in those who suffer from various thyroid disorders and normal control.We evaluate the consequences of pregnancy outcomes and determine management and therapeutic intervention in relation to pregnancy outcomes,providing to clinical obstetrician as a theoretically proof.Method:A descriptive analysis involving 149 pregnant women who visited and delivered in the first hospital of Shanxi Province from March 2008 to December 2008.Firstly,with high-sensitive chemical irradiance assay(CIA) technique,we analyzed the concentrations of thyroid stimulating hormone(TSH),free triiodo-thyroxine(FT3),free thyroxine(FT4) and TPOAb in pregnant women during their antenatal visit.According to the results of thyroid function tests assessed by standard laboratory reference ranges,we classified them into four different groups:overt hypothyroidism,subclinical hypothyroidism, normal and other thyroid dysfunction.The last group is excluded in this study.We pay attention to the prevalence of overt hypothyroidism & subclinical hypothyroidism as a whole.Then according to the stages of pregnancy,age of pregnant women,history of thyroid disease and other risk factors,we divide the groups above into several subgroups.We divided the pregnant women into groups according to different components of subclinical hypothyroidism and different levels of TSH.Then we can analyze the thyroid function without therapy.We intervene the patients with hypothyroidism and subclinical hypothyroidism.After several months of observation & follow-up,we got the final data of pregnant women with miscarriage,abortion and other complications to evaluate the effect of hypothyroidism and subclinical hypothyroidism on pregnancy.Results:①In this study,the prevalence of hypothyroidism is 2.68%(4/149),similar to the data of published articles,while the prevalence of subclinical hypothyroidism is 23.49%(35/149), much higher than the results having been reported.②There are four components of subclinical hypothyroidism,and in them groups of patients with simple TSH elevation & simple FT4 decreasing have higher ratios.③The levels of TSH in groups of patients with hypothyroidism & subclinical hypothyroidism are higher than those of the normal groups during the screening(P＜0.01) while decreasing of FT3 & FT4 is not obvious(P＞0.05).Thyroid function in controlled hypothyroidism group is in the reference range,and no significant difference is showed compared to the normal group(P＞0.05).④The ratio of positive TPOAb in a high-risk group was significantly higher than those without a past history of thyroid disease(P＜0.01).⑤We observed that significantly higher incidences of adverse obstetrical outcomes and complications in uncontrolled hypothyroidism group and subclinical hypothyroidism group compared with normal group(P＜0.01).The incidences of adverse outcomes is obviously increased in women who have a high risk than those without a past history of thyroid disease(P＜0.01).⑥According to the TSH level,we divide the study women into four groups,as TSH＞10 uIU/ml,TSH4.2-10 uIU/ml,TSH2.5-4.2 uIU/ml and TSH＜2.5 uIU/ml group.Following the raising of TSH level,the incidences of adverse outcomes and complications were increased.⑦The prevalence of hypothyroidism & subclinical hypothyroidism is much higher in the 3rd trimester.⑧The prevalence of subclinical hypothyroidism is much higher in the group of 21-25 years old pregnant women.Conclusion:Presence of clinical & subclinical thyroid disorders can negatively affect the pregnancy. However,if mothers with thyroid disease get adequate treatment in time and remain thyroid function normal,the adverse influence maybe reduced to the least.So serial monitoring and therapeutic intervention maybe necessary for the prevention of undesirable obstetric outcomes.