The clinical significance of placental histopathological evaluation in the management of high-risk obstetric patients: A cross-sectional retrospective study

Abstract

Background. Placental pathologies cause significant morbidity for both mother and fetus, and represent the largest category of causes of intrauterine death. Placental histopathology allows for recognition of treatment opportunities to prevent recurrence of adverse outcomes.
Objectives. To determine the indications for and findings of placental histopathological evaluation and assess the clinical use of the
findings in the management of high-risk obstetric patients. A secondary objective was to compare placental histopathological findings of patients with and without pre-eclampsia.
Methods. A cross-sectional retrospective study was performed at Charlotte Maxeke Johannesburg Academic Hospital, South Africa, on patients who had placentas submitted for histological evaluation at the time of delivery (1 June 2018 - 31 May 2019). The clinical indications, histopathology results and proposed follow-up plan in view of those results were analysed.
Results. We assessed 176 placental histopathology reports and hospital records. The most common indications were stillbirth (50.0%), pre-eclampsia (31.1%), late miscarriage (21.6%) and severe fetal distress (15.9%). The most common individual microscopic findings were increased syncytial knots (52.8%), patchy perivillous fibrin (48.9%) and chorioamnionitis (40.3%). The most common cluster diagnoses
were maternal vascular malperfusion (51.1%) and ascending infection (35.8%). Of our patient cohort, 55.7% received a follow-up appointment date and 44.3% did not, and 65.3% of patients with a follow-up appointment did not attend it. A management plan for future pregnancies was formulated for only 52.9% of those who attended their follow-up appointment. While statistically significant individual microscopic features were noted in cases of pre-eclampsia, the most important associations were identified between cluster diagnoses such as maternal vascular malperfusion and pre-eclampsia (p<0.0001) and ascending infection and pre-eclampsia (p=0.003).
Conclusion. This study showed that histopathology results are underutilised in formulating future management plans. In high-risk obstetric patients, management options for pregnancies must include review of previous placental histopathology results to prevent further adverse outcomes.