Acute Inflammatory Changes of the Placenta in Patients with Preterm Delivery Syndrome

Abstract

Preterm delivery is one of the most serious challenges of contemporary perinatology. Considering the multi factorial etiology of this issue, contemporary scientific approach addresses this topic as a Preterm Delivery Syndrome. If we exclude the congenital anomalies of the female reproductive system and iatrogenic causes, we can pinpoint infections, as one of the most important etiological factor for preterm delivery. The aim of the study is to determine the frequency of the histopathological changes of the placenta in patients with preterm delivery, to determine their stage and grade, according to the classification proposed by the Amniotic Fluid Infection Nosology Committee of the Perinatal Section of the Society of Pediatric Pathology (AFINCPSPP).  Finally, to define the correlation between those changes and the gestational age, as well as the correlation between the degree of the histopathological changes and the time passed from the preterm premature rupture of the fetal membrane and the delivery. This cohort prospective study includes 30 patients delivered at the University clinic for Ob/Gyn in Skopje. We’ve selected the patients according to the previously determined inclusion and exclusion criteria: gestational age between 24⁺⁰-34⁺⁰ weeks of gestation (w.g), premature preterm rupture of the fetal membranes (pPROM), presence of uterine contractions, cervical dilatation of ? 2 cm determined by vaginal examination or shortening of the cervical length by > 50% determined by vaginal ultrasound.

For the evaluation of the histopathological changes of the placenta, 6 samples were provided from four (4) zones of the placentas of the delivered women: chorionic plate, umbilical cord, border between amnion and chorion, and fetal membranes. Statistical analysis was performed on IBM SPSS Statistics software package, version 23.0. Probability of p?0.05 was considered statistically significant. Differences between descriptive variables were determined using Chi square and Fisher exact tests. For determination of correlation between variables, we used Kendall tau correlation coefficient. Of all the patients included in the study, 14 (46,7%) were at gestational age of 32⁺⁰-34⁺⁰ w.g, 7 (23,3%) were at gestational age of 28⁺⁰-31⁺⁶ w.g, and 9 (30 %) were at gestational age of 24⁺⁰-27+⁶ w.g. PPROM was registered in 14 (46,7%) of the patients, out of which almost half, 42,8 % were delivered in less than 24 hours after the rupture of the membranes. In 42,8% of the patients delivered between 32⁺⁰-34⁺⁰ w.g, histopathological analysis of the placenta did not detected presence of inflammatory response. On the other side, in patients delivered between 24⁺⁰-27⁺⁶ w.g,histological chorioamnionitis was present in all cases. Even more, in as high as 66,7% of these cases, inflammatory changes of the placenta were categorized as Stage 3, which is highest or most advanced stage of inflammatory response. Results of our study are consistent with previously published data. They confirm the inversely proportional relationship between gestational age at the time of delivery, and the stage and grade of histopathological changes of the placenta, defined as acute chorioamnionitis. Additional evaluation of the data showed that, there is no correlation between the degree of the inflammatory response, and the time passed from the pPROM and delivery, expressed in hours.