Comparison of gross morphological and histological features of placenta between hypertensive and normotensive pregnant women attending Muhimbili National Hospital.

Background: Placenta is the vital fetomaternal organ that is responsible for the maintenance of the pregnancy and promotion of fetal growth and development. The optimal survival, growth, and development of the fetus correspond to the appropriate formation and development of the placenta. Hypertensive disorders of pregnancy exert a great impact on the placenta and reflect changes both morphological and histological.  Objective: To compare the morphological and histological features of the placenta between hypertensive pregnant mothers and non-hypertensive pregnant mothers who attended Muhimbili National Hospital (MNH). Methods: A hospital-based cross-sectional study was conducted from June 2020 to August 2020 at Muhimbili National Hospital (MNH).  A total of 80 placentas were studied morphologically and histologically, of which 40 placentas were from hypertensive pregnant mothers and 40 placentas were from normotensive pregnant mothers. In the morphological aspect shape, weight, the site of insertion of the umbilical cord, the number of cotyledons of each placenta and thickness of the placenta were noted. In the histological part, Neutral buffered formalin (NBF) was used the routine staining technique which was Hematoxylin and Eosin (H&E) and a light microscope was used. The data were analyzed by using SPSS version 20 computer software and the results were summarized in means and proportions. ‘T-test’ and chi-square’ tests were used and the difference was statistically significant when the p-value>0.05   Results: The irregular shape of the placenta and marginal insertion of the umbilical cord were more in the hypertensive group and were statistically significant (p>0.01). The mean placenta weight, mean placenta thickness and mean numbers of cotyledons were significantly less in a hypertensive group compared to the normotensive group (p<0.01). A microscopic study of the placenta revealed the presence of fibrinoid necrosis, syntial knots, calcifications and villous hypoplasia in both normotensive and hypertensive group however these findings were significantly higher in the hypertensive group (p>0.01). Conclusion: Hypertensive disorders of pregnancy (HDP) exert a profound impact on the placenta. Morphologically altering its dimensions and histologically fibrinoid necrosis, calcifications, syntial knots, and villous hypoplasia were significantly more in the hypertensive group than in the normotensive (p>0.01).