To screen or not to screen for asymptomatic bacteriuria in pregnancy: A comparative three-year retrospective review between two maternity centres

Current national guidance in Ireland states that asymptomatic bacteriuria (AB) should be screened for at 12–16 weeks’ gestation and treated with a seven-day course of antimicrobials, due to the potential risk of preterm birth and low birth weight infants (LBWI), however, this is based on low quality evidence. Over a three-year period (2018–2020), a retrospective review was undertaken in two neighbouring maternity hospitals; one of which screens for AB (Rotunda hospital (RH)) and one which does not (National Maternity Hospital (NMH)). Patients were included on the basis of fulfilling the IDSA definition for pyelonephritis and requiring admission for intravenous antibiotics. Rates of antenatal pyelonephritis were compared between hospitals, and between screened and unscreened populations. Secondary outcomes including rates of preterm births and LBWI were compared across sites. A total of 47,676 deliveries between the two centres (24,768 RH; 22,908 NMH) were assessed, of which 158 patients met inclusion criteria for antenatal pyelonephritis (n = 88 RH, n = 70 NMH). There was no statistically significant difference in the rate of antenatal pyelonephritis (p = 0.34) or preterm births (p = 0.21) across sites. RH had a significantly higher rate of LBWI at 6.45% versus 5.68% of all births in NMH (p=