Analysis Of Prevalence And Influencing Factors Of Hypothyroidism In Pregnancy

Objective:Preliminary analysis of the prevalence of hypothyroidism in pregnancy（hypothyroidism）since the opening of the comprehensive two-child policy.To explore the relationship between the number of pregnancies,the number of deliveries,the time difference between the last pregnancy,age,body mass index（BMI）,glycosylated hemoglobin（HbA1c）,anti-thyroid peroxidase antibody（TPO-Ab）,anti-thyroglobulin antibody（TG-Ab）,adverse pregnancy history and hypothyroidism in pregnancy.So as to guide clinical work,strengthen the early screening and diagnosis of hypothyroidism in pregnancy,and timely intervention,effectively reduce the adverse consequences of pregnancy and avoid adverse effects on future generations.Methods:From March 1,2018 to October 31,2018,a total of 1140 pregnant women who were registered and hospitalized in the obstetrics department of the First Hospital of Shanxi Medical University were investigated by questionnaires.The results of thyroid function,HbA1c,age,height,weight and history of pregnancy and childbirth were collected.Pregnancy-specific thyroid function reference values published by ATA in2017（TSH reference values:T1:0.1-4.0 mIU/L,T2:0.2-4.0 mIU/L,T3:0.3-4.0 mIU/L）were used to diagnose hypothyroidism in pregnancy-Clinical hypothyroidism:（1）serum thyroid stimulating hormone（TSH）>4 mIU/L,and serum free thyroxine（FT₄）<lower limit of normal reference value（2）serum TSH>10 mIU/L,whether or not FT₄decreased;Subclinical hypothyroidism:serum TSH>4mIU/L,serum FT₄ within the reference range;Hypothyrothyroidemia:serum FT₄<the lower limit of normal reference value,TSH within the reference range of pregnancy-specific thyroid function.Statistical analysis was made on the collected data,and the proportion of clinical hypothyroidism,subclinical hypothyroidism and hypothyroidism in the patients with hypothyroidism during pregnancy was counted.The prevalence of hypothyroidism during pregnancy was compared between the first pregnancy and the second or more pregnant women.The number of pregnancies,the number of deliveries,the time difference between the last pregnancy,age,body mass index（BMI）,glycosylated hemoglobin（HbA1c）and anti-thyroidemia were defined.Whether thyroid peroxidase antibody（TPO-Ab）,anti-thyroglobulin antibody（TG-Ab）and adverse pregnancy history are the influencing factors of hypothyroidism during pregnancy.The data were analyzed by SPSS20.0software.The data of measurement data were expressed by mean（+standard deviation）（x±s）.Single factor analysis of variance was used for multigroup comparison,LSD-t test was used for two-group comparison,chi-square test was used for counting data utilization,and Logistic regression was used for multifactor analysis,P<0.05 was used for statistical difference.Results:A total of 1140 pregnant women were included in this study,including662first-trimester pregnant women（referring to primipara）and 478 second-trimester and above pregnant women（referring to multiparous women）.Among all the subjects,362had hypothyroidism,the prevalence rate was 31.75%.Among them,45 had clinical hypothyroidism,the prevalence rate was 3.95%.193 had subclinical hypothyroidism,the prevalence rate was 16.93%.124 had hypothyroidism,and the prevalence rate was10.88%.Among 662 first-born pregnant women,174 cases suffered from hypothyroidism,the prevalence rate was 26.28%.Among 478 second-born and above pregnant women,188 cases suffered from hypothyroidism,the prevalence rate was 39.33%,which was significantly higher than that of the first-born pregnant women group（P<0.05）.Age,BMI,TPO-Ab,TG-Ab,the number of pregnancies,the number of deliveries,the interval between pregnancy and the last pregnancy,and the history of spontaneous abortion were the single factors affecting the incidence of hypothyroidism in pregnancy,with statistical significance（P<0.05）.After excluding the confounding factors,age>29 years old,the number of deliveries>1 and the interval between pregnancy and the last pregnancy>120months were independent risk factors for hypothyroidism（P<0.05）,and the history of spontaneous abortion was the protective factor.Conclusion:The prevalence of hypothyroidism is higher in pregnant women,and the proportion of subclinical hypothyroidism is the highest.The prevalence of hypothyroidism in second and more pregnant women is significantly higher than that in first pregnant women.The risk of hypothyroidism in pregnancy was increased by age>29 years old,number of deliveries>1 and the interval between pregnancy and last pregnancy>120 months.Therefore,under the current situation that the number of second and more pregnant women is increasing gradually,more attention should be paid to hypothyroidism in pregnant women,so as to achieve early detection and treatment,avoid adverse pregnancy outcomes and reduce the impact on newborns.