Pathological features, clinical monitoring, and perinatal outcomes of placental thickening: a report of two cases.

Background: Placental thickening is a common clinical abnormality, the definition and clinical guideline for it are not clear. We herein reported two cases of isolated placental thickening (placental thickness >50 mm), with all physical examination findings and laboratory results within normal ranges. Both of the two patients were monitored closely and aggressively treated and led to favorable clinical outcomes. Case Description: One is a 35-year-old gravida 2 para 1 pregnant woman who was first indicated placental thickening at 24 weeks of gestation. She experienced vaginal bleeding with abdominal pain at 38+5 weeks of pregnancy and underwent emergency cesarean sections. The other one is a 32-year-old gravida 2 para 1 pregnant woman who was first indicated placental thickening at 31+1 weeks of gestation. She was found to have persistently low amniotic fluid since 36+6 weeks of pregnancy and an elective cesarean section was performed at 38 weeks. Conclusions: Placental thickening are easily observed clinically, it may be associated with various high-risk pregnancy conditions and adverse perinatal outcomes. However, there's no clear guidelines and only limited insights and data. Accordingly, these cases emphasize the critical clinical implications of placental thickening and proposes that close clinical surveillance is indispensable for improving maternal and fetal prognosis in patients with thickened placentas, with particular relevance to pregnant and postpartum women presenting exclusively with isolated placental thickening and no concurrent obstetric comorbidities.