Placentas From COVID-19-Positive Mothers: A Morphological Study of 20 Cases in Marrakesh, Morocco

Background Due to COVID-19, hospitals have seen a large influx of COVID-19-positive pregnant women. In order to study the impact of this virus on the infant and the possibility of its vertical transmission, we led a morphological study of 20 placentas from women infected or with a history of SARS-CoV-2 infection during pregnancy. Objective The aim of our study was to present the morphological characteristics of the placentas from these women and to correlate them with the clinical and biological findings, highlighting their relevance to pregnancy outcome and vertical transmission. Study design This is a retrospective, observational study, carried out at the pathology department of Mohammed VI University Hospital in Marrakesh over a one-year period from June 2020 to June 2021. The detection of SARS-CoV-2 by reverse transcription (RT)-PCR was carried out on the placental tissue and the newborns' urine and stools. Clinical information was taken from the medical records of patients in the gynecology and obstetrics department. The placentas received in our department were described and sampled according to the Amsterdam consensus. Results The mean age of the mothers was 29.85 years. Only one of them (1/20) had a history of cesarean section for severe preeclampsia. Thirteen (13/20) women had a positive nasopharyngeal PCR and were symptomatic at admission. Two critical states were noted: one case of severe preeclampsia complicated by hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome and another case of acute respiratory distress. Eight (8/20) deliveries were vaginally made and 12 (12/20) by cesarean section. The middle term of pregnancy was 36.7 weeks. Three cases of fetal death in utero (FDIU) were noted. There were no maternal deaths. The gross examination of our placentas revealed lesions in 18/20 cases. Placental vascular malperfusion lesions of maternal origin were predominant (16/20). Among these lesions, accelerated villous maturation (AVM) was found in 12/20 cases, central intervillous thrombosis (IVT) in 9/20 cases, and subchorionic intervillous thrombosis in 8/20 cases. Villous infarct lesions were found in 7/20 cases and were associated with a decidual arteriopathy in two cases. Placental vascular malperfusion lesions of fetal origin were found in 6/20 cases, with association to lesions of maternal origin in two cases. They all showed fetal vascular network lesions. The Inflammatory placental pathology was observed in only 4/20 cases. It was about one case of subchorionitis and three cases of acute chorioamnionitis associated with acute funiculitis. Massive perivillous fibrinoid deposition was found in 1/20 cases. The three fetal death in utero placentas were characterized by lesion multiplicity. Hypoxia-ischemia villous lesions were found in all of our placentas. Three newborns of positive mothers tested positive for SARS-CoV-2 RT-PCRs in their urine and stools. The corresponding placentas were also affected, including the one from the mother with HELLP syndrome. Conclusion SARS-CoV-2 Infection has no pathognomonic placental histopathological lesions. High rates of maternal origin lesions are reported in our study, suggesting abnormal maternal circulation. These results are generally concordant with those of the literature and justify close pregnancy monitoring.