Foley Catheter vs. Foley + Extra-amniotic Saline Infusion for Labor Induction at 41 Weeks and Beyond (FEASI)

Background and Rationale: Labor induction is the artificial initiation of contractions before spontaneous labor to achieve vaginal delivery. Mechanical methods, such as the Foley catheter, induce cervical ripening by creating physical pressure and stimulating the local release of prostaglandins. This study aims to provide evidence-based data on whether the addition of a continuous saline infusion (EASI) to the Foley catheter results in shorter labor durations and higher vaginal delivery rates compared to the catheter alone.

Study Design and Population:

• Design: A prospective, 1:1 randomized controlled clinical trial.
• Setting: All procedures are conducted under standardized aseptic conditions by trained operators in the delivery unit of Ankara Bilkent City Hospital.
• Sample Size: Based on a power analysis with an effect size of $d = 0.80$, a total of 60 to 64 participants (30 to 32 per group) will be enrolled to account for potential data loss.

Inclusion and Exclusion Criteria:

• Inclusion: Primiparous women , gestational age greater than or equal to 41+0 weeks , singleton pregnancy in cephalic presentation , reactive non-stress test (NST) with a biophysical profile greater than or equal to 8/10 , and a Bishop score less than or equal to 6.
• Exclusion: Multiple pregnancies , ruptured membranes , previous uterine surgery (e.g., Cesarean section) , placenta previa , fetal growth restriction (IUGR) , or high-risk systemic diseases such as severe heart disease or diabetes.

Study Procedures and Monitoring: Participants are randomly assigned to either the Foley group or the Foley+EASI group. Labor progress is monitored according to standard obstetric protocols. The study monitors several parameters, including the time from induction to active labor, total delivery time, and the mode of delivery.

Outcome Measures:

• Primary Outcome: Change in the Bishop score recorded 6 hours after induction.
• Secondary Outcomes: Vaginal delivery rate within 24 hours , Cesarean section rates and indications , maternal infection indicators such as fever greater than or equal to 38°C or chorioamnionitis , and neonatal outcomes including Apgar scores and birth weight.

Statistical Analysis: Data will be analyzed using descriptive statistics. Continuous variables will be compared using the Student's t-test or Mann-Whitney U test , while categorical variables will be evaluated using the Chi-square or Fisher's exact test. A p-value less than 0.05 will be considered statistically significant.