Morphological study of the placenta in deliveries with pre-eclampsia: Results from a prospective, observational study in India and Pakistan (PURPOSe)

Objective: To compare placental findings in women with and without pre-eclampsia. Design: The PURPOSe study included women with stillbirths, women with preterm births and women at term as controls. The placenta of each case was evaluated using the Amsterdam criteria. Setting: Two sites and five tertiary care hospitals of south Asia (Three in India and two in Pakistan). Population: Pregnancies in India and Pakistan with placental histology including women with documented hypertension and documented proteinuria and women with neither hypertension nor proteinuria. Methods: We compared the placental findings of the two groups using the Amsterdam criteria and further evaluated the placental findings in women with and without pre-eclampsia who had a stillbirth, preterm live birth, or term live birth (control). Main outcome measures: The main outcome measures were the frequency of maternal and fetal vascular malperfusion and the frequency of placental inflammation and its components, chorioamnionitis, funisitis, villitis and intervillitis in women with and without pre-eclampsia. Results: A total of 733 women had pre-eclampsia and 2334 women had neither hypertension nor proteinuria. In the placentas of women with pre-eclampsia, 57.3% had maternal vascular malperfusion compared with 37.1% in women without pre-eclampsia (p < 0.0001). There was not a significant difference in the prevalence of fetal vascular hypertension between mothers with (17.1%) and without (14.8%, p = 0.6118) pre-eclampsia. When placentas were classified as ‘histologically normal’ or not, 61.3% of those from pre-eclamptic pregnancies were classified as abnormal, whereas if there was no pre-eclampsia, only 45.0% were classified as histologically abnormal (p < 0.0001). We also considered rates of placental maternal vascular malperfusion in women with and without pre-eclampsia with stillbirth, preterm neonatal death, and term live birth. In women at term with no pre-eclampsia, 16.7% of the placentas had features of maternal vascular malperfusion. This occurred in 79.9% of women with stillbirths with pre-eclampsia compared with 51.8% of those without pre-eclampsia. Maternal vascular malperfusion was present in 49.7% of preterm live births with pre-eclampsia compared with 33.8% without pre-eclampsia. We also evaluated the inflammatory lesions by whether the mother had or did not have pre-eclampsia. When all inflammatory lesions were considered, women with pre-eclampsia had significantly fewer inflammatory lesions than those women without pre-eclampsia (17.1% versus 23.6% p = 0.001). Each of the specific inflammatory lesions was less common in placentas of women with pre-eclampsia than those with chorioamnionitis (16.1% versus 21.9%, p = 0.004) and funisitis (1.5% versus. 5.1%, p = 0.0004). Conclusions: Of placental lesions in women with pre-eclampsia, maternal vascular malperfusion was the most common. Inflammatory lesions were less common in women with pre-eclampsia.