Histopathological Changes of Placenta in Maternal Hypertensive Disorders and its Association with Birth Weight: A Case-control Study

Introduction: One of the most common complications during pregnancy is hypertension. It leads to pathological changes which reduce the placental blood flow. Hypertensive disorders are strongly associated with foetal growth restriction, prematurity, lower foetal birth weights and contribute largely to perinatal mortality and morbidity.

Aim: To study the histomorphological changes of placenta in cases of maternal hypertensive disorders and compare it with normal controls as well as find out its association with neonatal birth weight.

Materials and Methods: A case-control study was conducted at the Department of Pathology of a Tertiary Care Hospital, Faridabad, Haryana, India. Duration of the study was two months from July to August 2018. This study is a part of Indian Council of Medical Research (ICMR) Short Term Studentship (STS) scheme for MBBS students. Control group was formed by 30 placenta of full term deliveries without any complications and 30 placenta of the females presenting with hypertensive pregnancies formed the case group. Specimens of placenta were studied in detail for morphological and histological changes. Neonatal Birth weight was recorded just after delivery of all the cases and controls. Analysis of statistical difference between the means of both groups was performed using student unpaired t-test. The data obtained was entered in Microsoft excel sheet and statistically analysed using Epi Info version 7.

Results: Mean maternal age for cases was 28.60 years and controls were 25.23 years. This association was found to be significant. Mean for gestational weeks at the time of delivery was 34.93 weeks in cases and 37.20 weeks in controls (p-value <0.0001). Average placental weight in cases was 410.20 grams and in controls was 480.80 grams (p-value <0.001). Histopathological changes comprised of syncytial knot formation, cytotrophoblasts proliferation, proliferation of endothelial lining of capillaries, stromal fibrosis, calcification, hyalinisation of villi and infarction were comparatively more frequent in cases (n=30). Mean neonatal birth weight was found to be 2809.67±128.32 grams in control group as compared 2427.67±152.22 grams in cases (p-value <0.001).

Conclusion: During pregnancy significant histomorphological changes in placenta are caused due to hypertensive disorders which lead to harmful and severe foetal outcomes. A valuable insight into the mechanism of placental dysfunction can be achieved through a detailed examination after delivery.