Correlation of COVID positivity on L&D with community positivity and wastewater monitoring

The mutation capability and community transmission of COVID-19 may continue to strain the healthcare system with episodic surges in the foreseeable future. Vaccines are effective at reducing hospitalization; however, obstetric patients are unique in that many will be inevitably hospitalized for delivery. Reliable community indicators to predict positivity rate of laboring patients could help physicians and administrators better plan for the allocation of resources and implement best practices for infection control. We hypothesized that community positivity rate and wastewater viral load correlate with COVID positivity of laboring patients. Labor and Delivery patients from March 2020 to July 2022 were reviewed and weekly COVID positivity census was compiled (n= 584/10,169). During this time there was universal screening with laboratory testing for all patients regardless of symptoms. In May 2022 routine testing was paused, but then restarted in June 2022. These data were compared to county Department of Health and Human Services community test positivity rates and CDC wastewater surveillance program data from the same period. The percentage of COVID positive patients on L&D was highly correlated with both wastewater viral load (F1,101 = 71.4, P< .001) and community positivity rate (F1,102 = 144.1, P< .001). A spike in labor and delivery COVID positivity rate proceeded a corresponding peak in hospitalization rates by an average of two weeks (F1,102 = 27.9, P< .001). The trend was consistent across the three COVID “peaks” during the study period (Figure 1). Positivity rate of labor and delivery patients is highly correlated with community positivity and wastewater viral load. Pregnant patients screened on L&D are also a bellwether for impending surges in overall hospital COVID positivity rate.