ABSTRACT
Background: COVID-19 can cause placental histopathological changes through associated inflammatory responses, maternal hypoxia and hypoperfusion, with subsequent placental microvasculopathy and fetal hypoxia. We hypothesise that these placental changes will cause placental insufficiency, as reflected by histopathological abnormalities and fetal distress on a cardiotocography (CTG), that correlates with disease severity. Methods: During the Delta wave, Monash Medical Centre was the only referral centre for pregnant women with COVID-19 in Victoria, Australia. Three groups undergoing caesarean section prior to the onset of labour were identified: 13 women with severe COVID-19 requiring hospitalisation, 53 with asymptomatic/ mild illness and 10 with placental insufficiency without COVID-19. CTGs and placental histology were analysed for evidence of maternal and fetal hypoxia. Results: Placental histology was obtained in 12/13 of severe, 40/53 asymptomatic/mild and 8/8 cases of placental insufficiency without COVID-19. Histopathological abnormalities were associated with COVID-19 disease severity;severe (8/12, 67%) and asymptomatic/mild (24/40, 60%) compared with 100% (8/8) in the placental insufficiency group. Maternal vascular malperfusion was seen in 58%, 15% and 75% and inflammatory changes in 17%, 30% and 0%, respectively (Table 1). Abnormal CTGs reflecting fetal hypoxia were seen in 77% of severe COVID-19 cases and in 49% with asymptomatic/mild illness (Table 2). Conclusions: Both mild/asymptomatic and severe COVID-19 illness are associated with high rates of CTG and placental abnormalities. These changes are similar to those seen with other causes of placental insufficiency. Therefore, increased surveillance and delivery from >37 weeks should be considered in women with COVID-19 in pregnancy, regardless of disease severity. (Table Presented).