2019 Volume 249 Issue 3 Pages 231-236
Thyroid dysfunction (TD) is caused by thyroid peroxidase (TPO) antibody, as seen in Hashimoto’s disease. TD is a common problem of reproductive age and may impair fetal development. Here, we determined the effect of TPO antibody on perinatal outcomes in Japanese women with TD before conception. A retrospective study involving cases of maternal TD with term singleton birth was conducted. The subjects with TD were divided into two groups according to the presence (n = 22) or absence (n = 20) of TPO antibody. The control groups matched for age, parity, and gestational weeks were selected for TPO antibody-positive (n = 44) and -negative TD subjects (n = 40), respectively. Using the standard curve of Japanese placental weight, the frequency of placental weight less than the 50th percentile (small placenta) was examined. Placental weight was lower among TPO antibody-positive TD subjects, compared with TPO antibody-negative TD subjects (p < 0.01). However, other outcomes were similar between the groups. Importantly, compared with control mothers, placental weight was significantly lower (p < 0.01), birth weight tended to be lower (p = 0.07), and the incidence of gestational diabetes mellitus was higher (p = 0.02) among TPO antibody-positive subjects. There was no significant difference in placental weight between TPO antibody-negative subjects and controls. The frequency of small placenta was significantly higher in TPO antibody-positive subjects (odds ratio: 16.7) even when considering diabetes and pregnancy induced hypertension. Thus, the presence of TPO antibody is associated with lower placental weight among Japanese women having TD.
