Induction of Labor With a Foley Balloon Catheter: Inflation With 30ml Compared to 60ml

All potential candidates will be approached for the study and undergo written consent if willing to participate. Each candidate will be randomized to 30ml or 60 ml Foley balloon catheter volume. A random number generator will be used and within a sealed envelope will be placed the assignment. Nulliparous and multiparous patients will be randomized separately. The patient will be positioned for a standard cervical exam - either for digital or speculum exam, depending on the individual patient preference and provider choice. For digital exam, a sterile Foley balloon catheter will be digitally placed in the endocervical canal, into the extraamniotic space (between the fetal head, external to the unruptured amniotic sac, above the internal os of the cervix). For speculum exam, the cervix is wiped three times with a Betadine cleansing solution, and a sterile Foley balloon catheter bulb will be placed under direct visualization into the endocervical canal, into the extraamniotic space. Once the balloon is in place the provider inserts 30ml of sterile saline. The provider then leaves the room. The patient's nurse opens the envelope and if the patient is allocated to the 60ml volume group, the nurse adds an additional 30ml of sterile saline. If the patient is in the 30ml group, the RN staff will simulate placement of additional saline into the foley balloon without actually placing any additional saline in order to also blind the patients to their assigned group. The MD/CNM providers will then return to the room, blinded to the inflation of the Foley balloon, and the balloon catheter will be placed under tension by taping the external end to the patient's inner thigh. Oxytocin will be started within 30 minutes of the Foley balloon catheter placement, using the standard intravenous oxytocin protocol. Additional manual traction on the Foley balloon catheter will be performed every 30 minutes until Foley balloon catheter expulsion. A sterile cervical exam will be performed after spontaneous Foley catheter expulsion to evaluate post-balloon cervical dilation. No further procedures or tests specific to this study will be required beyond this point; only data collection on the above study outcomes during the remaining course of the patient's labor will be recorded.

Inclusion criteria

• Reproductive aged women, pregnant, term gestation (>37 weeks), undergoing induction of labor, cervical exam acceptable as a candidate for Foley balloon catheter placement (Bishop score <5), cephalic fetal presentation.

Exclusion criteria

• Regular contractions on admission, rupture of membranes, previous uterine scar, low-lying placenta (measured <3cm to internal os), Bishop score > 5, contraindication to attempt at vaginal birth, non-English/Spanish speaking, unable to give consent.