Objectives: To assess the antibacterial efficiency of filters used in obstetrics when epidural top-ups are performed. Study design: Observational prospective study. Patients and methods: We aseptically collected 201 antibacterial filters that had been used for top-ups with ropivacaine ± sufentanil for epidural analgesia during labour. We flushed them first with 2 mL of saline and then with 2 mL of a solution containing 1.5 ×10 6 Staphylococcus epidermidis/mL. The filtrates were incubated at 37 °C for 72 h. Number of top-ups and duration of epidural analgesia are expressed as median (extremes). Results: 3 (1-10) top-ups were performed for labour analgesia over a period of 6,5 h (1,8-18). After filtering, all the solutions were found to be sterile. Especially, when using Staphylococcus epidermidis solutions, bacteria were not found beyond any filter. These results suggest the integrity of the filter membrane after several boluses. No infection related to epidural analgesia was reported. Conclusion: Antibacterial filters provide a good protection against a potentially contaminated procedure during epidural top-ups.