Maternal Thyroid Function and Biochemical Markers of Placental Function in Early Pregnancy
ABSTRACT
Objective
A link between maternal thyroid function and the placental biomarkers, soluble fms‐like tyrosine kinase‐1 (sFlt‐1) and placental growth factor (PlGF), has been brought forward. This study aimed to describe their association in early pregnancy.
Design
Retrospective cohort study.
Participants
Eight hundred and fifty‐eight pregnant women from the North Denmark Region, 2013, with blood samples drawn in early pregnancy.
Measurements
Thyroid‐stimulating hormone (TSH), free thyroxine (fT4), thyroid‐peroxidase antibodies (TPO‐Ab), thyroglobulin antibodies (Tg‐Ab) (ADVIA Centaur XPT, Siemens Healthineers), sFlt‐1 and PlGF (Kryptor Compact, ThermoFisher Scientific) were measured. The association between maternal TSH and fT4 and percentile (pc) levels of sFlt‐1 and PlGF (< 25th pc, 25–75th pc, > 75th pc) was evaluated using regression analysis and reported as adjusted beta coefficient (aβ). The frequency of maternal thyroid autoantibodies (TPO‐Ab > 60 U/mL or Tg‐Ab > 33 U/mL) by pc levels of sFlt‐1 and PlGF was compared using chi‐squared test.
Results
Higher levels (> 75th pc) of sFlt‐1 associated with lower TSH (aβ 0.62, 95% CI: 0.51–0.76) and higher fT4 (aβ 1.03, 95% CI: 1.01–1.05). Higher levels of PlGF associated with lower TSH (aβ 0.82, 95% CI: 0.69–0.98), but not with levels of fT4 (aβ 1.00, 95% CI: 0.97–1.02). No association with maternal thyroid autoantibodies was found (TPO‐Ab: sFlt‐1: p‐value 0.5 and PlGF: p‐value 0.1; Tg‐Ab: sFlt‐1: p‐value 0.7 and PlGF: p‐value 0.1).
Conclusions
In a large cohort of Danish pregnant women, higher levels of sFlt‐1 and PlGF associated with maternal thyroid function in early pregnancy, while there was no association with maternal thyroid autoantibodies.
