A randomized trial of labour induction using the Foley catheter of different bores (French sizes 16, 22 and 28: 1 French size equals 0.33 mm)

INTERVENTION: Randomisation is by the opening of sealed opaque and numbered envelope with lowest available envelope assigned in strict order. Randomization sequence is generated using a random number generator at Random.org in random block of 6 or 9 sequence, generated by investigator who is not involved in recruitment. Participants are randomised into 3 arms; 16 F, 22 F and 28 F. Only specified investigator performs the intervention using standardised protocol in all group. Participants are placed in lithotomy position. The provider performs a vaginal examination under aseptic condition to identify the os. Insertion is by slitting the Foley catheter along the operator’s hand and fingers lubricated with water soluble lubricant into endocervical canal. Once the tip of the catheter is past the internal os, the catheter is filled with 60mL of sterile water and then retracted so that the balloon rested on the cervical os. The external end of the Foley catheter are taped without tension to the medial aspect of the women’s thigh. In the event of a failed insertion a vaginal speculum method of insertion using the same catheter bore are attempted if the participant consents. This method involves inserting a sterile Cusco speculum lubricated with water soluble lubricant into the vagina to visualise the cervix followed by a sponge forceps guided threading of Foley catheter into the cervical canal. Following successful insertion of Foley catheter, standard institutional care applicable to Foley catheter labour induction shall apply. CONDITION: Induction of labour ; Pregnancy and Childbirth ; Induction of labour PRIMARY OUTCOME: 1. Catheter Insertion time (total minutes to successful catheter placement at first attempt); 2. Patient reported pain (VNRS 0 to 10, taken immediately after first attempt with successful insertion); 3. Patient pain score by Insertion failure rates (placement time more than 5 minutes, procedure abandon by provider or requested by participant during insertion, catheter unable to pass through cervical canal or inadvertent amniotomy); SECONDARY OUTCOME: Maternal outcomes:; 1. Time of catheter expelled or evacuated; 2. Maternal satisfaction with their care since allocation to the intervention until removal of catheter; 3. Use of additional prostaglandin for cervical ripening; 4. Use of oxytocin for intrapartum augmention; 5. Use of regional analgesia in labour; 6. Timing from intervention to delivery; 7. Mode of delivery and indication/s of caesarean section; 8. Estimated postdelivery blood loss; 9. Fever (intrapartum and up to patient discharge); ; Neonatal outcomes: ; 1. Apgar score at 1 and 5 minutes; 2. Arterial cord pH ; 3. Birth weight; 4. Neonatal admission INCLUSION CRITERIA: 1. Women with unfavourable cervix undergoing cervical ripening and induction of labour at term in University Malaya Medical Centre, Kuala Lumpur 2. Scheduled induction of labour 3. Aged 18 years and above 4. Gestational age of > 37 weeks at enrolment 5. Unfavourable cervix (Bishop Score = 5) 6. Reassuring pre induction fetal cardiotocography (CTG) 7. Cephalic presentation 8. Singleton pregnancy 9. Intact membranes