Study On The Level Of Estrogen,Progesterone And The Expression Of Their Receptors In The Related Target Tissues In Prolonged Pregnancy

Objective:Our study was designed to determine whether prolonged pregnancy is associated with change of the estrogen and progesterone receptor in myometrial and placental tissue, and the concentration of estradiol and progesterone in aminotic fluid and maternal serum.Methods:Maternal serum and aminotic fluid samples were assayed for estradiol and progesterone by radioimmunoassay. Jmmunocytochemistry and morphometry were used to determine the expression and quantitative evaluation of estrogen and progesterone receptor in the lower myometrial segment and placental tissue obtained at cesarean delivery from prolonged pregnant and term pregnant women.Results:In the pathologically postmature pregnancy, placental villi were increased in number, but reduced in volume. The avascular villi and villi with fibrinoid necrosis were increasingly found, the intervillous spaces became narrow and fibrin deposits appeared frequently. Syncytial knots were formed excessively. The cytotrophoblasts were hyperplastic and the trophoblastic basement membrane became thicker and irregular.As compared with the term pregnancy not in labor, the concentration of progesterone in aminotic fluid of prolonged pregnancy not in labor was3slgnlhcantly ilgher and the estrogen－progesterone ratio was lower．Incontrast,no slgnlhcantdlfferences ofestradlol andprogesteroneconcentration In maternal serum or amlnotlc fluid were detected In pregnantwomen In labor．However,the estradiol concentration and estradiolprogesterone ratio In maternal serum and amlnotlc fluid were higher foundInpregnantwomen In labor thanthose not In labor． Myometrlum and placenta ofpregnant women contained estrogen andprogesterone receptors．lhese receptors werepresent Inplacentalsyncytlotrophoblasts andmyometrlal smoothmuscle cells．Thelmmunostalning Intensity for progesterone receptor was higher In womenwlthprolongedpregnancythanthose wlthtermpregnancy,onthe contrary。the estrogen receptors were less In them．Simultaneously,he estrogen－progesterone receptor ratio was lower In prolonged pregnancy．Comparingwlthnot Inlabor,the women In labor displayed more estrogen receptors butless progesterone receptors and a higher estrogen－progesterone receptorratio．COllClllSIOll: The morphology ofpostmature placenta Is associated wlththe decreaseof placental functions． The lower estradlol－progesterone ratio was related wlthprolongedpregnancy,and the higher estradiolprogesterone ratio was associated Withthe Initiation oflabor．A decrease ofestrogen－progesterone receptor ratio Inmyometrlal and placental tissue might play a important role In theoccurrence olprolongedpregnancy．Elevated estrogen－progesteronereceptor ratio Is associated wlththe onset oflabor．since estradlol and 4progesterone exert actions via their receptors, and modulate the receptor levels in the target cells, both hormones and receptors are key factors for maintaining pregnancy and initiating labor.