Isolated maternal hypothyroxaemia in third trimester linked to pre-eclampsia
In the study, first (week 9–12) and third (week 32–36) trimester serum samples were collected from 6,031 mothers (aged 21–43 years) for analyses of thyroid function. All of the women had singleton pregnancies, were Han Chinese, had no history of thyropathy or autoimmune disease, no goiters, were thyroid peroxidase antibody (TPOAb)-negative, and did not use medicines that would affect thyroid hormone levels. In addition, all had TSH levels within the reference intervals during the first and third trimesters of pregnancy. Women were monitored for adverse pregnancy outcomes such as gestational diabetes mellitus (GDM), pregnancy-induced hypertension, and pre-eclampsia.
The researchers found that women who were older and those who had a higher pre-pregnancy body mass index were more likely to experience hypothyroidism. Although pregnancy-induced hypertension was not significantly correlated with FT4, GDM, and pre-eclampsia were inversely correlated with maternal FT4 levels during early and late pregnancy, respectively. In particular, women with IMH during the third trimester had an increased risk of developing pre-eclampsia.