INDUCTION OF LABOUR Flashcards
How does cervical ripening take place?
Pharms to efface, dilate or soften the cervix in order to increases likelihood of NVD
-done by exogenous and endogenous release of PGs
What is the difference between induction of labour(IOL) and augmentation of labour
IOL- initiation of contractions in a pt who isn’t in labour to help here have a NVD within 24-48hrs
AOL-women who is already in labour is given oxytocin to speed up contractions
List fetal issues that indicate IOL
- IUGR in a singleton
- concurrent conditions eg. Oligohydromnious, maternal co-mobirdity such as PET, chronic HT
- DCDA twins with isolated IUGR
- DCDA twins concurrent conditions eg. Abnormal Doppler study, maternal co-morbidities
List maternal issues that indicate IOL
- chronic HT (controlled with or without meds, difficult to control )
- gestational HT
- pre-eclampsia (mild and severe)
- pregestational DM (well controlled, poorly controlled, with vascular complications)
- gestational DM( well controlled by diet and meds or poorly controlled)
List the contra-indications of IOL
- any contra-indication to NVD
- placenta previa
- cord prolapse or compression
- abnormal fetal lie
- prior classic C/S(transverse), prior uterine surgery, previous uterine rupture
- active genital herpes
- pelvic abnormalities
- invasive cervical Ca
What is the assessment of pre-induction of labour?
- Bishops score( success score >7)
- parity
- BMI
- maternal age
- DM
- estimated fetal weight(EFW)
How does the Bishop score work?
Score Dilate efface station consi CP
0 closed >4 -3 firm ant
1 1-2 3-4 -2 Med Mid
2 3-4 1-2 -1 soft Ant
3 5-6 0 +1,+2 - -
How can IOL be prevented?
- Routine early U/S to determine accurate gestational age to prevent post term pregnancies and therefore prevent IOL
- strip membranes at 39 weeks gestation
What happens when the bishop score is unfavourable?
Induce cervical ripening, thinning and softening
How is the cervix mechanically ripened?
- Insert a 18Fr Folley cathether(balloon) into the intracervical canal past the int. os (pressure to int. os to stretch it= release of PG)
- The bulb of the catheter is inflated with 30-60ml H2O
- The Catheter is left there until it falls out within 24hrs, otherwise manually removed to prevent infection
- Advantages- simple, reversible, reduced side effects
- Contra- indications - low lying placenta( APH, ROM, LGUT infections)
How is the cervix pharmacologically ripened?
PGE2(prandin, prepidil, dinoprostone)
- advantages: better pt acceptance, less need for oxytocin, less op risk than oxytocin
- disadvantage: expensive, needs to be refrigerated
*If PGE2 unsuccessful, opt for ROM or oxytocin 6hrs after PGE2
What is the most common drug used to ripen the cervix
Misoprostol(synthetic PGE1)
- Adv: stable @ room temp, cheap, multiple routes of admin, rapid onset of action
- Dose: 200microgram in 200ml H2O and then admin 20ml every 2hrs for 12 doses
- monitor CTG before and after each dose
- side effects: hyper stimulation or rupture of uterus, MSL
- contra-indications: grand multiparty, previous C/S, uterine surgery
What happens when the cervix(if membranes are accessible) or bishop score are favourable?
Amniotomy(AROM) if:
- committed to delivery
- no contra-indications: placenta previa, vasa previa, GUT infections
- Risks: cord prolapse due to lowered presenting part and polyhydramnios
- Liquor assessment: amount, colour, consistency and fetal wellbeing via CTG
Oxytocin
- High dose and low dose
- high: high hyperstimulation, less time to get to labour
- low: low hyper stimulation, less cardiac effects
- can be used in VBAC
- use CTG to monitor fetus
What are the complications of IOL?
Uterine rupture
- rare but life threatening
- occurs in absence of scarred uterus
- also due to uterotonic use in obstructed labour
Define failed IOL
- failure to get to the APL
- failure to go into labour after more than 24hrs of cervical ripening
