Establishment Of Reference Range Of Specific Thyroid Function In Pregnant Women And Clinical Analysis The Relationship Between Hypothyroidism And Pregnancy Outcome

OBJECTIVE: To establish the reference range of trimester-specific thyroid hormone in our hospital,and to explore the impact of chronic lymphocytic thyroiditis(Hashimoto's thyroiditis),hypothyroidism combined with thyroid peroxidase antibody(TPO-Ab)and thyroglobulin antibodies(TG-Ab)negative on adverse pregnancy outcome.METHODS: Thyroid stimulating hormone(TSH),free thyroxine(FT4)and free iodine thyroid glycine(FT3)levels were retrospectively collected from pregnant women with regular prenatal examination in our hospital from January 2018 to June 2019.In addition to,the pregnancy outcomes and neonate status of chronic lymphocytic thyroiditis,pregnancy hypothyroidism(TPO-Ab and TG-Ab negative)and normal pregnant women were retrospectively compared.RESULTS:(1)in the first trimester,there were 1217 pregnant women were collected,the 95% reference range of serum TSH was0.04-3.73uIU/ml,13.15-23pmol/L for FT4 and 3.8-6.2pmol/L for FT3.646 in the second trimester,the serum TSH was 0.1-4.03uIU/ml,10.7-20.1pmol/L for FT4,and 3.3-5.7pmol/L for FT3.1287 in the third trimester,the serum TSH was 0.68-4.32uIU/ml,9.8-17.4pmol/L for FT4,and 3.1-5.0pmol/L for FT3.(2)There were 182 pregnant women in Hashimoto's group,180 in hypothyroidism group and 180 in normal control group.Compared the incidence of previous abortion in three groups,the Hashimoto's group(31.4%)were significantly higher than hypothyroidism group(17.4%)and normal group(4.8%).There was statistically significant difference(P < 0.05).(3)In Hashimoto's thyroiditis group,the incidence of premature birth,gestational diabetes mellitus(22.5% and 6.6% respectively)was higher than that in antigen-negative hypothyroidism group(2.8%,16.7% respectively)and the normal group(1.7%,11.1% respectively).There were statistically significant differences(P<0.05).(4)The incidence of fetal growth restriction in Hashimoto's group was 6.6%,which was higher than that in hypothyroidism group(2.2%)and normal group(1.1%).There was no statistically significant differences(P<0.05).But there were no significant differences in birth weight,body length,Apgar score,blood gas analysis of PH and BE among the three groups(P>0.05).CONCLUSION: The reference range of thyroid function in different gestational periods is different and fluctuate with gestational weeks.Therefore,establishing the reference range suitable for specific thyroid hormone is essential for screening and diagnosing.Pregnancy complicated with chronic lymphocytic thyroiditis will increase the risk of miscarriage,premature delivery,fetal growth restriction and gestational diabetes mellitus.In order to diagnose thyroid diseases early and reduce the risk of adverse pregnancy outcome,thyroid function and TPO-Ab and TG-Ab should be screened during pregnancy.