Specialist care of chronic urine infections in pregnancy leads to good pregnancy outcomes

Objective: To describe pregnancy outcomes of women with chronic urinary tract infection (cUTI) under specialist care. Design: Retrospective cohort study. Setting: UK tertiary Lower Urinary Tract Symptoms (LUTS) Clinic. Population or sample: Pregnancies in women attending the LUTS Clinic between 2015-2023 with a cUTI diagnosis. Methods: Routinely-collected clinical data was analysed. Clinical care was guided by pyuria, measured using urinary white blood cell counts (WBC) by manual microscopy. WBC counts were normalised as relative change from preconception baseline and categorised as low, moderate, or high. Urine culture was not used. Main outcome measures: Urinary WBC counts, pregnancy outcome, pyelonephritis, preterm birth, maternal and neonatal complications. Results: 345 women with 411 pregnancies were identified with outcome data available for 289 pregnancies. Antimicrobials included cefalexin, nitrofurantoin and methenamine hippurate. There were predominantly term livebirths (203/289, 70.2%, 39 weeks’ gestation [IQR 38-40]) followed by early miscarriage (63/289, 21.8%). Outcomes included maternal pyelonephritis (4/289, 1.4%), moderate-late preterm births (13/163, 6.7%), congenital abnormalities (4/289, 1.4%), neonatal unit admissions (4/203, 2.0%) and neonatal carnitine deficiency secondary to maternal pivmecillinam use (2/203, 0.01%). Low preconception pyuria patients maintained stable disease throughout pregnancy, whereas moderate-high preconception pyuria patients experienced worsening antenatal disease with postnatal flare. Patients with previous poor outcomes achieved term livebirths following disease stabilisation with antimicrobial treatment. Conclusions: Specialist cUTI management in pregnancy showed pregnancy outcomes comparable to the UK population. Preconception disease stabilisation appears key to favourable outcomes. Long-term antimicrobial use in pregnancy including methenamine hippurate appears to be safe.