Objective: To evaluate the effect of cycle threshold (Ct) values on the pregnancy outcomes of women with coronavirus disease 2019 (COVID-19).
Materials and methods: This prospective cohort study was conducted on pregnant women with COVID-19. A real-time polymerase chain reaction (RT-PCR) assay of a nasopharyngeal and oropharyngeal specimen was used for the diagnosis. Initial Ct values for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RT-PCR tests were recorded. 22.9 was the 50th percentile Ct value of the study population. The study population was divided into two groups based on their Ct values: (1) Cases with Higher Ct values (Ct > 22.9)(n = 50) and (2) Cases with lower Ct values (Ct ≤ 22.9)(n = 55). Demographic features, clinical characteristics, disease progression, laboratory test results and pregnancy outcomes were compared between the groups. A receiver operating characteristic (ROC) curve was used to assess the performance of Ct values in predicting obstetric complications.
Results: Obstetric complication rate was significantly higher in cases with lower Ct values (p < .001). A significantly lower lymphocyte count together with higher ESR, procalcitonin and IL-6 values were observed in the cases with lower Ct values (p > .05). Additionally, a significantly higher NICU admission rate and longer hospital stays were present in the cases with lower Ct values (p > .05). The value in ROC curves with the best balance of sensitivity/specificity was 22.5 (85.7% sensitivity, 63.6% specificity).
Conclusion: Lower Ct values may be associated with an increased rate of obstetric complications in pregnant women with COVID-19. Physicians should be cautious in the management of cases with Ct levels below 22.5.
Keywords: COVID-19; SARS-CoV-2; cycle threshold; obstetric complications; pregnancy.