ABSTRACT
First-trimester chorion villosum plays the key role in the development of human placenta and secretes a large number of hormones and hormone-related substances. To test whether progesterone and estrogen could have regulatory effects on first-trimester chorion villosum functions, we investigated the presence of progesterone receptor (PR) and estrogen receptor (ER) in 47 chorion villosum samples from patients who underwent abortion during the first trimester of pregnancy. The study was carried out using immunohistochemical methods. No ER and PR positivity was evidenced in the 47 chorion villosum samples examined. The possibility that progesterone and estrogen play a role in the regulation of chorion villosum functions should therefore be excluded.
