The Impact Of Maternal Subclinical Hypothyroidism On Pregnancy Outcome

ObjectiveTo dicuss the influence of maternal subclinical hypothyroidism(SCH)and its intervention on pregnancy outcome.Methods1.The study was surveyed in population taking their prenatal care in kunshan hospital affiliated to Jiangsu university.part 1:To establish the reference range of specific serum thyroid function in pregnancy in 1st?2nd?3rd trimester(T1,T2,T3).A total of 2,984 healthy pregnant women who were taking their prenatal care from January 2015 to December 2015 were selected for the study,including 1,189 cases at stage T1 and 1420 cases at stage T2.,375 cases of stage T3.2.Part 2,A total of 5,072 pregnant women who set up CARDS in the obstetrics clinic and gave birth in hospital between January 2016 and December 2017 were selected as subjects.Then we cross-sectional with them.The reference range of specific serum thyroid function in pregnancy was used as reference to calculate the occurrence of each thyroid diseases during pregnancy.To investigated the relationship between TPOAb?timelimit in pregnancy and the occurrence of thyroid diseases.The changes of FT4 and TSH during pregnancy were studied by frequency distribution.3.Part 3,Among 5072 subjects,The above patients were compared in groups according to different diagnostic criteria,In order to firther understand the effect of subclinical hypothyroidism during pregnancy on pregnancy outcome and the range of reference that is used to diagnose subclinical hypothyroidism.STEP1:Taking the reference range recommended by the 2011 American thyroid association guidelines(hereinafter referred to as the ATA guidelines)as the standard,200 pregnant women with TSH level between 2.5-10mmol/L?normal TSH and TPOAb negative in 1st trimester with SCH were selected,The pregnant women were divided into treatment group and observation group according to their voluntary choice of drug treatment under the condition of full informed consent.Among them,96 patients were treated with L-T4(the treatment group),and 104 pregnant women were not treated with drug intervention(the observation group).133 women with normal in 1st trimester with TSH<2.5mIU/L and TPOAb negative were selected as the control group(control group).The general data,abortion rate,pregnancy complications and neonatal complications of the three groups were compared.STEP2:Combined with reference range of specific serum thyroid function in pregnancy.developed by this unit,and the aim to compare the outcomes of the pregnant women and the need for drug interventions,We used 1st trimester pregnancy women whose TSH was 4.12mIU/L as the upper limit of the specific reference range,then studied 38 cases(treatment group)and 58 cases(observation group)with TSH between 2.5-4.12mIU/L.Results1.Trimester-specific reference intervals of thyroid function indices for pregnancy in this region is,1st trimester:TSH:0.02-4.12mIU/L;FT4:12.11-20.66 pmol/L;2 nd trimester:TSH:0.03-4.64 mIU/L;FT4:10.94-19.02 pmol/L;3 rd trimester:TSH:0.59-4.73 mIU/L;FT4:10.09-17.48 pmol/L.2.Among the 5072 pregnant women,clinical hypothyroidism incidence was 0.37%(19/5072),subclinical hypothyroidism incidence 3.23%(164/5072),low T4 incidence 2.21%(112/5072)and TPOAb positive rate was 14.22%(721/5072).TPOAb>60U/ml was used as positive group(divided into TPO positive group and TPO negative group),we found that the incidence of thyroid diseases was higher in all the pregnant women with positive TPO than negative.The incidence of SCH during pregnancy was significantly increased in positive TPO(5.13%vs2.92%).P=0.0040),The cross-sectional survey was conducted in early,middle and late pregnancy groups,and it was found that the detection rate of each hypothyroidism in early pregnancy was relatively high,and the number of new cases gradually decreased with the progress of pregnancy.The incidence rate of SCH was still the highest in pregnancy.In describing The frequency distribution of TSH and FT4 in pregnancy,we found that the peak value of FT4 was shifted to the left and TSH was shifted to the right as pregnancy progresses.3.Compared between groups,the incidence of abortion in the observation group was higher than that in the control group(10.58%vs3.01%).P=0.02965).The abortion rate in the treatnent group was lower than that in the observation group after drug intervention(2.08%compared with 10.58%;P=0.02371).And there was no difference in the incidence of gestational diabetes,gestational hypertension,premature rupture of membranes,amniotic fluid,postpartum hemorrhage,premature delivery,macrosorrua,fetal growth restriction,neonatal asphyxia,and neonatal transmission between the observation group and the control group,or between the treatment group and the observation group.4.We further selected pregnant women with TSH between 2.5-4.12mIU/L in the treatment group and observation group,and also compared with the normal control group,to analyze the complications such as pregnancy outcome and neonatal outcome.It was found that there was no statistically significant difference in the rate of abortion,gestational diabetes,gestational hypertension,premature rupture of membranes,amniotic fluid,Postpartum hemorrhage,Premature delivery,macrosomia,fetal growth restriction,neonatal asphyxia,and neonatal transfer between the treatment group and the observation group and the control group(P>0.05).Conclusion1.It is recommended to establish the reference range of specific serum thyroid function in pregnancy to the region or the unit.2.The incidence of thyroid diseases during pregnancy is high,and the screening and management of pregnancy should be strengthened.3.During pregnancy,SCH increases the risk of miscarriage,When TSH was between 2.5-4.12mIU/L,the incidence of pregnancy complications and neonatal complications did not increase,Therefore,we do not recommend L-T4 intervention for these pregnant women.It is suggested that the diagnosis and treatment of thyroid diseases in pregnancy should be based on reference range of specific serum thyroid function in pregnancy.