Trial of Foley Catheter With and Without Extra-Amniotic Saline Infusion for Labor Induction

In the United States, labor inductions have increased from 11% of all pregnancies in 1989 to 21% in 2004. Although the indications for labor induction vary, labor inductions as an obstetrical practice are associated with an increased risk of Cesarean delivery. As such, the rise in labor inductions has been paralleled by a rise in the cesarean rate to an all time high of 30%. The risk of cesarean can be mitigated with the use of cervical ripening agents in the setting of an unfavorable cervix. Both pharmacological ripening agents and mechanical methods are currently available for cervical priming. Methods available for mechanical dilation include, but are not limited to transcervical foley catheter alone and transcervical foley catheter with an extra-amniotic saline infusion or EASI. The potential advantage of EASI to transcervical foley catheter alone is the promotion of endogenous prostaglandin release by membrane stripping and supplying additional mechanical force. It may be disadvantageous by increasing the risk of chorioamnionitis or by diluting the prostaglandins that are released by membrane stripping. There have been two randomized trials comparing foley alone to foley with EASI. Because the results of these two trials are conflicting, we chose to conduct a randomized clinical trial of foley catheter compared to foley catheter with an EASI for labor induction and cervical ripening in women with an unfavorable cervix.