Universal screening for SARS-CoV-2 in pregnant women at term admitted to an East London maternity unit.

Objective: To explore the prevalence of asymptomatic SARS-CoV-2 in the maternity population.

Study Design: Newham University Hospital based in East London serving a population with the highest death rate secondary to SARS-CoV-2 in the UK, commenced universal screening of all admissions to the Maternity Unit from 22nd April to 5th May, 2020. A proforma was created to capture key patient demographics, indication for admission and presence of SARS-CoV-2 related symptoms at the point of presentation.

Results: A total of 180 women with a mean age of 29.9 (SD 7.4) years, at a median gestation of 39 (IQR 37 + 1-40 + 3) weeks underwent universal screening with nasopharyngeal PCR swabs during the two-week period of the study. BAME identity or parity was not associated with the likelihood of a positive result. Seven women (3.9 %, 1.6-7.8) were tested positive for SARS-CoV-2, of whom 6 (3.3 %, 1.2-7.1) were asymptomatic; 85.7 % (42.1-99.6) of the SARS-CoV-2 positive women were asymptomatic. The sensitivity of symptom-driven testing was 14.3 % (0.36-57.87) and specificity was 91.86 % (86.72-95.48) with a positive predictive value of 6.67 % (1.08-31.95) and a negative predictive value of 96.34 % (95.10-97.28).

Conclusion: The prevalence of SARS-CoV-2 in the maternity population served by Newham University Hospital was 3.9 %, four weeks after lockdown. Of the women who were found to be SARS-CoV-2 positive, a high proportion (87.9 %) were asymptomatic. These findings support the need for universal testing to enable targeted isolation and robust infectious control measures to mitigate outbreaks of SARS-CoV-2 in maternity units.