Cervical ripening: how long can the Foley catheter safely remain in the cervical canal?

This was a prospective study involving 85 patients admitted for induction of labour with unfavourable cervix at Usman Danfodiyo University Teaching Hospital, Sokoto, Nigeria. A size 16-20 Foley catheter was passed transcervically into the extra-amniotic space under aseptic technique and the balloon inflated with 30-50 mls sterile water. Each patient was placed on prophylactic antibiotics. The balloon was expelled within 12 hours in 22 (39%) patients. Twenty eight patients expelled the balloon in 12-24 hours, 14 in 25-48 hours, 6 in 49-72 hours and 4 after 72 hours. The average duration of catheter placement when the gestational age was 20-27 weeks was 44.8 hours, which was significantly longer than 19.6 hours obtained for term pregnancies (p < 0.05). Induction of labour was successful in 77 (91%) patients and there was no significant maternal morbidity. The results of our study suggest that the balloon of the Foley catheter can safely remain in the extra-amniotic space longer than 24 hours for cervical ripening if the cervix is unfavourable, provided the membranes are intact and the feto-maternal conditions remain satisfactory.