Placental Villous Changes Among Hypertensive and Normotensive Pregnant Women at Kenyatta National Hospital

Abstract

Background Hypertensive pregnancy disease is a major cause of maternal morbidity and mortality in Africa, complicates 2.73% of pregnancies in Kenya and is one of the major causes of maternal deaths in Kenyan public health facilities. Hypertensive disease in pregnancy, particularly preeclampsia, has been associated with placental villous histomorphological changes. Few studies have been done elsewhere to demonstrate these changes and have found different and conflicting findings. Additionally, there are still few requests for placental histopathological evaluation by clinicians in Kenyatta National Hospital and in other hospital settings probably due to a perceived low clinical utility. This study hypothesized that established associations between placental villous histopathology and clinical variables such as maternal blood pressure status and neonatal outcomes adds to the available evidence and help sensitize clinicians on the need for histological examination of placentae. Study Objective The main objective of this study was to determine placental villous changes among hypertensive and normotensive pregnant women who delivered at Kenyatta National Hospital. Materials and Methods This was a laboratory based retrospective cross-sectional analytical study design carried out at the University of Nairobi (UoN) Histopathology Laboratory. The study made use of archived placental tissue blocks obtained from hypertensive pregnant women and their normotensive counterparts who delivered at Kenyatta National Hospital between July and December 2015. All available specimens (n=138) were retrieved, processed and analyzed. Data was entered and analyzed using SPSS version 20. Proportions of villous histomorphological findings were compared between hypertensive and normotensive groups. A Chi square test of association was used to determine association between the villous histomorphological findings and

hypertensive pregnancy disease. Association between villous histomorphological findings and the different clinical groups of hypertension in pregnancy was determined using Fisher’s exact test. Villous histomorphological findings was associated with neonatal outcomes using Chi square test. Results Placentae from women with hypertensive pregnancy disease at Kenyatta National Hospital had significantly higher rates of accelerated villous maturity, distal villous hypoplasia, stromal fibrosis, decidual arteriopathy, villous infarction and an increased area (>25%) of intervillous fibrin deposition (p<0.01). The Pre-eclampsia-eclampsia clinical group had placentae characterized by lesions associated with placental ischemia supporting evidence that placental hypoperfusion could be characteristic of pre-eclampsia-eclampsia rather than gestational hypertension. Villous histomorphological findings associated with poor neonatal outcomes include accelerated maturation, villous hypoplasia, villous infarction, stromal fibrosis and decidual arteriopathy. Recommendation Sensitization of clinicians in Kenyatta National Hospital on the clinical utility and need for placental histopathological examination in the following clinical scenarios among others: intrapartum management of hypertensive pregnant women, postmortem evaluation of unexplained maternal mortality where hypertensive pregnancy disease needs to be ruled out and evaluation of poor neonatal outcomes for possible aetiology. Future studies should use multiple and variably selected representative sections of the placental disc with equal sampling from all the hypertensive disease groups to enable better comparisons.