Screening of thyroid function during pregnancy and the analysis of security of treatment to subclinical hypothyroidism

Objective To investigate the necessity for screening of thyroid function during pregnancy, and the safety and efficacy of gestational subclinical hypothyroidism levothyroxine replacement therapy. Methods 964 pregnant women less than 20 weeks for obstetric examination from April 2009 to April 2010 were selected and accepted thyroid function screening.Subclinical hypothyroidism women were divided into the treatment group and control group.The treatment group received 50～75μg L-T4 according to TSH level while the control group received no intervention.The levels of TSH and TT4 were reviewed every four weeks until delivery and perinatal outcomes were observed and analyzed statistically for the two groups.Results TSH value for 964 cases of pregnant women first screening range from 0.011 to 14.047 mU/L,mean 1.568 mU/L,P2.5 0.078 mU/L,P5 0.190 mU/L,P95 3.568 mU/L,P97.5 4.571 mU/L 2 cases were diagnosed as clinical hypothyroidism(0.2%incidence),2 subclinical hyperthyroidism(0.2%incidence) and 68 subclinical hypothyroidism (7.05%incidence).No L-T4 treatment adverse pregnancy outcome occurred for 23 SCH pregnant women.The difference of perinatal outcome between the treatment group and the control group was not statistically significant Conclusions The incidience of thyroid malfunction was high in pregnant women of Shenzhen City.It is necessary to screen the thyroid function during pregnancy and it is safe for mother and child to receive appropriate dose of levorotatory thyroid hormone replacement therapy during pregnancy period.