Context.- A severe third wave of COVID-19 disease affected Ireland in the first 3 months of 2021. In this wave, 1 second trimester miscarriage and 6 stillbirths were observed in the Irish population due to placental insufficiency as a result of SARS-CoV-2 placentitis. This observation was at odds with the country's previous experience with COVID-19 disease in pregnant mothers. Objective.- To describe the clinical and pathological features of these pregnancy losses. Design.- Retrospective review of clinical and pathological data of cases of second trimester miscarriage, stillbirth or neonatal death identified by perinatal pathologists as being due to SARS-CoV-2 placentitis during the third wave of COVID-19 in Ireland. Results.- Clinical and pathological data was available for review in 6 pregnancies. Sequencing or genotyping of the virus identified SARS-CoV-2 Alpha (B.1.1.7) in all cases. Three of the 6 cases had maternal thrombocytopenia, while fetal growth restriction was not prominent suggesting a rapidly progressive placental disease. Conclusions.- The identification of SARS-CoV-2 Alpha in all these cases suggests that the emergence of the variant was associated with an increased risk of fetal death due to SARSCoV-2 placentitis when compared to the original virus. Maternal thrombocytopenia, may have potential as a clinical marker of placentitis but other inflammatory markers need investigation. Three of the 6 women had been assessed for reduced fetal movements in hospital some days before the fetal deaths actually occurred; this could suggest that there may be a window for intervention in some cases.

Cesarean sections have increased worldwide and there is an increasing awareness of the adverse long-term sequelae associated with the procedure. The World Health Organization estimates that there are approximately 18.5 million women who undergo this procedure annually, with rates in the Western world increasing from 14.5% to 27.2% between the years 2000 and 2017. 1 A cesarean scar niche, first described in 1961 when a wedgeshaped defect was noted in the uterine wall of a patient who had previously had a cesarean section during hysterosalpingography, 2 is defined as the presence of a hypoechoic area and discontinuation

Accurate 3D models of placenta accreta spectrum (PAS) are achievable and may provide additional information such as distance of the defect from the internal os.

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