Placental apoptotic index on COVID-19 and non-COVID-19 cases: a cross sectional study

Backgrounds: Rare cases of COVID-19 vertical transmission are reported, even though abnormal findings on placenta histopathology are frequently reported on SARS-CoV-2 infected pregnancies. However, no publications report the impact of COVID-19 infection on the placental apoptotic index. Apoptosis is a physiological process of cell regeneration. SARS- CoV-2 infection during pregnancy may disturb the respiration system, causing hypoxia, thus altering placental perfusion. COVID-19 infection also increases inflammatory mediators, producing reactive oxygen species and affecting placenta tissue in viremia cases. These processes can cause caspase cleavage, resulting in programmed cell death and apoptosis. This study aims to know whether COVID-19 infection with various degrees of symptoms affects placental apoptosis. Methods: This is a retrospective, cross sectional study. We conduct a study on 34 placenta blocks of COVID-19 pregnancy and 31 placenta blocks of non-COVID-19 pregnancy. The PCR of nasopharyngeal swabs performed on third-trimester patients in Dr. Soetomo Hospital meets the inclusion and exclusion criteria. Those placenta samples were processed into slides and painted with a TUNEL assay kit. Slides are then examined and rated for apoptotic index. Results: The majority of these patients are multiparous women. Sixty-five patients were included in the study, 2 died, and 63 others lived. Comparison between COVID-19 positive and non-COVID-19 placental apoptotic index shows a significant difference between both groups (p=0.001). Conclusion: From this study, we can conclude that there is a significant difference in the apoptotic index of the placenta between COVID-19-positive and negative pregnancies.