1. Induction of Labor

2. Objectives Definitions Indications and contraindications
Pregnancy dating
Comparison of methods
Management considerations

3. Induction
initiation of uterine activity and cervical change with fetal descent by pharmacological or other means in a woman who is not in labor.

4. Cervical Ripening
promotion of cervical change by pharmacological or other means
not primarily intended to induce labor but to increase the success of subsequent induction

5. Contraindications to Induction
Any contraindication to labor

6. Indications for Induction
when continuation of the pregnancy is a greater risk to the mother or fetus than the risk of induction and delivery
must be convincing, compelling, fully discussed and documented

7. Indications - Emergent
severe gestational hypertension
suspected acute fetal compromise
severe IUGR
significant maternal disease not responding to treatment
significant APH
chorioamnionitis

8. Indications - Urgent PROM at term or near term
IUGR without evidence of acute compromise
poorly controlled diabetes mellitus
isoimmune disease at term or near term

9. Indications - Non-Urgent
'post-term' pregnancy
well controlled diabetes mellitus
intrauterine death in a prior pregnancy
intrauterine fetal demise
logistic problems (rapid labours, distance to hospital)

10. Indications - NOT elective induction
induction, in the absence of maternal or fetal indication, should not be undertaken

11. Risks of Induction failure to achieve labour
uterine hyperstimulation with fetal compromise
uterine hyperstimulation with uterine rupture
increase risk of C/S

12. Labour Induction Methods Likelihood of Successful Vaginal Delivery
MOST
MOST
favourable
multiparous
previous vaginal
cervix
delivery
unfavourable
nulliparous
cervix
previous C/S
LEAST
LEAST

13. If attempted induction does not achieve labor reevaluate the indication and method of induction

14. Methods of induction include mechanical and pharmacological means.
The best choice depends on the cervical score (A cervix is unfavorable if the Bishop score is < 6)

15. Bishop Scoring System Factor 1 2 3 Dilatation (cm) 1 - 2 3 - 4 > 5
Score
Factor 1 2 3
Dilatation (cm)
1 - 2
3 - 4
> 5
Effacement (%)
0 - 30
> 80
Consistency
Firm
Medium
Soft
Position
Posterior
Mid
Anterior
Sp -3 or
Sp +1 or
Station
Sp -2
Sp -1 or 0
above
lower

16. Effect of Cervical Status on C/S Rate50
Nulliparous
Parous 40 34 30 23 20
Cesarean Section (%) 20 13 12 6 10
0-3
>3
Spontaneous Labour
Cervical dilatation at induction
Xenakis Obstet Gynecol (1997) 90: 235

17. Labour Induction - Unfavourable Cervix
Stripping of membranes
Cervical ripening followed by oxytocin
laminaria / artificial tents
Foley catheter
prostaglandins
Prostaglandins (intracervical or vaginal)
Amniotomy or oxytocin

18. Mechanical Methods catheters and tents
cause cervical softening and effacement
this may facilitate an early amniotomy
these methods are effective by producing local prostaglandin along with direct dilatation
less hypertonus and FH rate abnormalities than with pharmacologic agent

19. Prostaglandin Preparations
Vaginal preparations are:
easier to administer
easier to remove
less likely to be placed extra-amniotically
less likely to cause patient discomfort

20. Prostaglandin E2 myometrial contraction cervix
causes collagen breakdown and proteoglycan deposition
vasodilator
bronchodilator
GI motility and secretory effects

21. Prostaglandin E2 - Route and Dose
intracervical (Prepidil )
prostaglandin E mg into cervical canal
vaginal (Prostin E2 vaginal gel )
prostaglandin E2 1 or 2 mg into posterior fornix
vaginal (Cervidil vaginal insert)
prostaglandin E2 10 mg into posterior fornix
any formulation may be used for cervical ripening

22. Guidelines for PGE2 Use insertion in hospital by experienced caregiver
monitor appropriately for FHR and uterine activity
if labour develops manage as appropriate
if no labour, reassess, repeat as necessary or choose an alternative induction method

23. Prostaglandin E2 - Advantages
improved patient acceptance
lower operative delivery rate
less need for oxytocin induction
may be used in PROM
cost considerations

24. Prostaglandin E2 - Disadvantages
adverse reactions
hyperstimulation
CVS events
nausea, vomiting, diarrhea
gel preparations are difficult to remove
cost considerations

25. Precautions with Prostaglandins
avoid placing PG’s adjacent to myometrium
use cautiously in patients with previous C/S
do not repeat more frequently than every 6 hours
wait 6 hours prior to oxytocin infusion following gels
may be started 30 minutes after Cervidil removal
do not use for augmentation

26. Labour Induction - Favourable Cervix
Stripping of membranes
Amniotomy
Oxytocin
Vaginal prostaglandins

27. Amniotomy creates commitment to delivery
effective with favourable cervix
often used in conjunction with oxytocin
caution in cases of high presenting part ( risk of cord prolapse)

28. Oxytocin Effects myometrial contraction cervix - no direct effect
vasoactive
hypotension possible with bolus IV administration
antidiuretic activity
water intoxication possible with high dose oxytocin

29. Oxytocin Guidelines cervix should be favourable
experienced caregivers and access to caesarean delivery
auscultation or EFM depending on indication
administration
intravenous
concentrations vary but avoid large free water load

30. Uterine Hypertonus discontinue oxytocin if in use intravenous bolus
prepare for emergency delivery
consider tocolytic agents
ritodrine at mg/min IV until desired effect
nitroglycerin 50 mg IV push to maximum of 200 mg
nitroglycerin spray sublingual

31. Post partum consideration:
if oxytocin was used in labor, PPH may occur
for all induced patients , give oxytocin bolus post partum ( oxytocin 10 units I.M. 20 units 1L at 100 cc/hr for 2 hours or more

32. Conclusions
reasons for induction must be compelling, convincing and documented
risk and benefits must be discussed with patient
patient preference must be considered
ripen the cervix as much as possible
match the method with the urgency and cervical status
do not use oxytocin if cervix unfavourable
don't overestimate your ability to succeed

33. happy baby + happy mom + vaginal delivery
Goal of Induction
avert anticipated adverse outcome associated with continuation of pregnancy
to effect uterine activity sufficient for cervical change and fetal descent without causing uterine hyperstimulation or fetal compromise
to allow as natural a birthing experience as safely possible and maximize maternal satisfaction
happy baby + happy mom + vaginal delivery