Cefazolin versus placebo for surgical antibiotic prophylaxis in low-risk cesarean delivery: a feasibility blinded randomized controlled trial.

Background: Pre-incisional antibiotics are recommended for all patients having cesarean delivery, despite emerging concerns regarding effects on the infant. In this feasibility blinded randomized controlled trial we aimed to test research processes in low-risk women receiving cefazolin or placebo prior to elective cesarean delivery.

Methods: The trial was prospectively registered (ACTRN12619001705178). Eligible women were aged ≥ 18 and < 40 years, ≥ 37 weeks gestation, at low risk of surgical site infection (SSI) and recruited from a single tertiary centre. We reported proportions of women eligible and consenting; adherence to perioperative infection prevention; blinding adequacy of staff using Bang's blinding index; SSI surveillance and diagnosis according to the Centre for Disease Control definitions and patient reported outcome measures using validated questionnaires up to 90 days.

Results: We screened 1651 women, with 1245 (75%) ineligible based on body mass index or presence of diabetes. Of 287 eligible women, 30 were randomized (11%) with 15 in each group. Reasons for non-participation included "wanting antibiotics" (68, 27%), "no reason" (62, 25%) and lack of research staff (33, 13%). Compliance with perioperative infection prevention occurred in 5 of 7 steps. Spontaneous placental separation occurred in 25 (83%) and Comfeel dressing in 29 (97%). Blinding was adequate for all staff groups. SSI surveillance occurred in 156 of 210 (74%) timepoints. SSI occurred in two patients who received pre-incisional cefazolin and were successfully treated as outpatients. Patient reported outcome questionnaires were completed at 136 of 180 (76%) timepoints. There was no difference in maternal health-related quality of life between the groups.

Conclusions: Feasibility was impacted by the high-risk population and patient desire for antibiotics. Adherence to perioperative infection prevention practices were high but incomplete. These study processes could be effectively applied in a larger population, targeting low risk maternity patients.

Trial registration: Prospectively registered 4/12/2019 with the Australian New Zealand Clinical Trials Registry (ACTRN12619001705178).