A preliminary study on the pregnancy outcomes of pregnant women with positive thyroid peroxidase antibody

Abstract

Objective To explore the correlation between simple thyroid peroxidase antibody(TPOAb)positive(higher than the normal reference value )and the adverse pregnancy outcomes; and to discuss the necessity of clinical intervention on TPOAb positive and the characteristic of gestational thyroid peroxidase antibody changes. To study wether clinical intervention affects its direction. Methods Subjects were selected from TPOAb positive pregnant women during June 2012 to February 2015. They were registered regularly for thyroid function during pregnancy and 6 weeks postpartum, and timely treated for abnormal thyroid function. They were grouped according to the thyroid function: Group 1(n=122), simple TPOAb positive group; Group 2(n=67), patients with elevated TSH and positive TPOAb who accept the levothyroxine(L-T4)intervention; Group 3(n=120), TPOAb negative healthy pregnant women. They were regularly tested for thyroid function during pregnancy, and with follow-up until 6 weeks postpartum. Results When Group 1 compared with Group 3: the risk of premature rupture of membranes, abnormal amniotic fluid, and fetal distress rate increased, the relative risk(RR)were 3.066, 4.782, 2.605, all P 0.05). When Group 2 compared with Group 3, the risk of premature rupture of membranes, abnormal amniotic fluid, and fetal distress increased(RR were 3.830, 5.537, 3.600 respectively, all P 0.05). Compared with Group 2, Group 1 had no statistical difference between the above observational parameters. The levels of TPOAb from stage T1(the first trimester)to T3(the third trimester)showed a overall downward trend in Group 1 and Group 2, rise again six weeks after child birth. Comparison of the two groups(Group 1 and Group 2), the median value during this period did not reveal any significantly statistical differences(P>0.05). Conclusion In simple TPOAb positive pregnant women, premature rupture of membranes, abnormality in amniotic fluid, and fetal distress were significantly higher than those in healthy pregnant women; even with thyroid function correction the TPOAb positive pregnant women still cannot reduce the adverse pregnancy outcomes. Levels of TPOAb from T1 to T3 presented the overall downward trend and to rise again six weeks after pregnancy. L-T4 intervention for TPOAb positive pregnancy did not show any significant effect.(Chin J Endocrinol Metab, 2015, 31: 1041-1045) Key words: Pregnancy; Thyroid peroxidase antibody; Pregnancy outcomes