The prevalence of inflammatory process in placentas from premature births in different gestational periods

Abstract

Premature birth (PB) is the birth in less than 37 weeks, which can be spontaneous and iatrogenic, its frequency reaches 10% of all births. The pathogenesis of premature labor is based on the inflammatory reaction of the chorion, amnion and decidual membrane, but the origin of the inflammatory reaction is different depending on the gestational age.The objective: to study the prevalence of the inflammatory response in placenta samples from very early preterm, early preterm and term births.Materials and methods. Placenta samples from 203 parturient women who gave birth in the gestational period of 22–27 weeks – very early PB (I group – 101 parturient women with premature rupture of membranes (PROM), II group – 102 parturient women with the onset of labor with intact membranes) and 202 parturient women were examined with deliveries in the period of 28–34 weeks – early PB (III group – 100 women in labor with PROM and IV group – 102 women in labor with the onset of labor with intact fetal membranes) and 60 women in labor with term deliveries.Immunohistochemical detection of CD8, CD3 and CD14 antigens in villi was used to assess the prevalence of the inflammatory process and compare it between groups.Results. In 56.7% of placentas from term deliveries no markers of villousitis were detected, a mild form of villousitis was found in another third of cases. In placentas of woman with the onset of labor between the 28th and 34th weeks with intact fetal membranes there were signs of villousitis in 54.9%, and its mild manifestations in 33.3%. In the case of premature rupture of the membranes, the prevalence of villousitis reached 65%, its severe forms were more often observed.On the other hand, in the groups of very early PB only 14.9 and 15.7% of placentas had no signs of vilouisitis, one in five placentas from these groups had severe focal or diffuse villousitis. In the group of early PB and intact amniotic membranes, one third of the placentas demonstrated an isolated CD3 lymphocyte marker, no antigen was detected in 47.1% of placentas, and only in every tenth placenta antigens of macrophages of fetal origin were determined. A similar distribution was found in placentas from early PB with PROM.In placentas from very early PB the highest frequency of CD14 detection was found – every second placenta contained this marker in isolation and in 22.5% – in combination with maternal lymphocyte markers. In the group of very early PB on the background of PROM placentas with a positive CD14 test dominated – 31.7% isolated and 45.5% in combination with CD3.Conclusions. 1. In placentas from premature births (PB) at 28–34 weeks, villousitis was detected in 54.9% of cases against the background of intact amniotic membranes and in 65.0% – on the background of premature rupture of the membranes, from very early PBs – in 85.1% and 83.3%, respectively. Placentas from deliveries with premature rupture of the fetal membranes more often had signs of severe villousitis – in 21% of cases at 28–34 weeks and in 20.6% at 22–27 weeks.2. In placentas from early PB, macrophage antigen of fetal origin was detected in 22% of cases in the cases of premature rupture of the fetal membranes and in 21.6% of cases of childbirth with intact membranes; these samples were dominated by infiltration by lymphocytes of maternal origin. On the other hand, placentas from very early PB and ruptured fetal membranes in 77.2% of cases contained antigen of fetal macrophages and in 71.6% of cases of onset of labor with intact membranes.Such results indicate the fetal origin of the inflammatory process in very early PB.