Influence of positive serum thyroid peroxidase antibody on pregnancy outcomes

Abstract

Objective To investigate the influence of positive serum thyroid peroxidase antibody (TPOAb) on pregnancy outcomes in biochemically euthyroid women during gestation.Methods From July 2006 to December 2010,in the prenatal care unit all pregnant women,who had no medical and family history of thyroid diseases,underwent thyroid function screening.Serum TPOAb was tested among those pregnant women with euthyroidism.Pregnancy outcomes,including obstetric complications,neonate birth weight,and Apgar score,were compared between 185 TPOAb positive women and 1417 TPOAb negative women.Results Compared with TPOAb negative women,it was more frequent for TPOAb positive women to suffer from various obstetric complications.The prevalences of umbilical cord entanglement ( 18.9％ vs 12.9％,RR =1.47,95％ CI 1.06-2.03,P＜0.05 ),threatened premature delivery or abortion (3.8％ vs 1.0％,RR =3.83,95％ CI 1.57-9.37,P＜0.05 ),intrauterine growth retardation (5.4％ vs 0.8％,RR =6.96,95％ CI 3.00-16.17,P＜0.01 ),and neonatal pneumonia ( 4.9％ vs 1.3％,RR =3.83,95％ CI 1.75-8.40,P＜0.01 ) in the group of TPOAb positive women were higher than those in the group of TPOAb negative women.Apgar score of those newborns whose mothers had positive TPOAb was 9.27 ±1.13 at one minute and 9.44 ± 1.09 at five minutes,being lower than that of the TPOAb negative group (9.49 ±0.69 and 9.68 ±0.52,both P＜0.01 ).The rate of newborns with Apgar score at 7 or less by 5 min in group with positive TPOAb was higher than that of group with negative TPOAb ( 1.6％ vs 0.1％,RR =11.49,95 ％ CI 1.93-68.31,P＜ 0.05 ).Conclusions These results indicate that pregnant women with normal thyroid function but positive TPOAb may be liable to increase risk of serious pregnancy outcomes,such as threatened premature delivery or abortion,intrauterine growth retardation,and a lower Apgar score in neonatal. Key words: Pregnant woman; Thyroid peroxidase antibody; Obstetric complication; Apgar score