Thyroid stimulating hormone receptor expression in human placenta and decidua

Objectives Elevated Thyroid Stimulating Hormone (TSH) concentrations have been associated with adverse pregnancy outcomes. We hypothesise that TSH could have a direct impact on uteroplacental development. We, therefore, sought to describe the ontogeny of TSH receptor (TSHR) in the human placenta and decidua. Methods Human placenta (n= 90, 7-42 weeks gestation) and decidua (n=36, 7-20 weeks gestation) were obtained. Total RNA was reversed transcribed for quantification of mRNA encoding TSHR by TaqMan RT-PCR using 18S as an internal reference. Western immunoblotting and immunohistochemistry was performed to determine protein expression and localisation within placental tissue. Results Overall, mRNA encoding TSHR was detectable in 66% of placental samples and 42% of decidual samples. Expression of TSHR mRNA was found in 83% of term placentae compared with only 53% of first trimester placentae. There was increasing placental TSHR mRNA expression with advancing gestation (ANOVA p