1. Induction of Labor Controversies, Criteria, and Consequences
Jamie Otremba, CNM, APRN, MSN

2. Definition of Induction of Labor:
Stimulation of uterine contractions prior to the onset of spontaneous labor to accomplish delivery.

3. Incidence of Induction% %
trending down, slowly. (30%)
40-75% elective
No improved outcomes with increased rate of induction
20% of pregnancies require induction

4. WHY? Patient desire/convenience Provider lifestyle/balance
Economic reasons for providers
Concern over increased incidence of complication over 39 wks

5. Induction of labor should be undertaken when the benefits to either the mother or fetus outweigh the risks of continuing the pregnancy.
-ACOG

6. Medical Indications: ACOG Committee Opinion 560: Medically-Indicated Late-Preterm and Early-Term Deliveries
Placental/uterine issues
Previa, myomectomy
Fetal issues
IUGR, multiples, oligo
Maternal issues
Chronic HTN, diabetes
Obstetric issues
PROM
2/3 are for nonmedical reasons

7. Suspected fetal macrosomia is not an indication for labor induction: it does not improve outcomes. -ACOG

8. Elective induction of labor
The major risks:
iatrogenic prematurity
increased rates of cesarean delivery (67% incr risk)
increased cost

9. Requirements for Induction
Confirmation of term gestation >39 wks if elective
Favorable cervix per Bishop Score
≥ 8 for multip, ≥ 10 for a prime
No ripening for electives
Informed consent
Indications/alternatives
Techniques
Possibility of cesarean delivery, failed induction
Increased risk of more intervention
Possibility of cancelation

10. Induction Checklists ACOG Intermountain Healthcare Include
Indication: elective vs. medical (document)
Gestation and how it was established
Bishop score
EFW
Consent obtained
Pertinent lab work
Hard stop

11. Most important factor in predicting success: Favorable cervix

12. Predicting Success Bishop score CERVIX 1 2 3 Position Posterior Mid
Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964;24:266-8.
CERVIX 1 2 3
Position
Posterior
Mid
Anterior --
Consistency
Firm
Medium
Soft
Effacement
0-30%
40-50%
60-70%
>80%
Dilation
Closed
1-2cm
3-4cm ≥5
Station -3 -2
-1, 0
+1,+2,+3
low Bishop score is particularly predictive of failure in nulliparous women who undergo elective induction of labor at term, although Bishop scoring was originally described in multiparous women
The role of fFN as a tool for selecting women likely to have a successful induction remains uncertain. More data, including cost-benefit analysis, is needed before this test can be recommended in choosing candidates for semi-elective induction.
More data, including cost-benefit analysis, is needed before this test can be recommended in choosing candidates for semi-elective induction

13. % C-Section by Bishop Score Primiparous Women

14. Hours of Labor by Bishop Score Primiparous Women

15. Cervical Ripening for Medical Induction of Labor
Complex process that results in physical softening and distensibility of the cervix
Enzymatic dissolution of collagen fibrils
Increase in water content of the cervix
Chemical changes contribute to effacement and early dilatation

16. Cervical Ripening Mechanical methods Chemical methods Time
Effectiveness impacts induction success rate

17. Weekly membrane stripping
No improvement in outcomes
May cause concerns and result in hospital evaluation: $$
Form of induction: not before 39 wks
Most benefit with multips
May increase labor in next hrs, and more likely to go into labor in the next 7 days
Lowers risk of post-term pregnancy
Spontaneous delivery is more likely
Caution if GBS pos

18. Amniotomy Partially dilated and effaced cervix
Shortens delivery timing by 2 hrs with oxytocin
Not effective alone as induction agent
Risks
Infection barrier is removed
Cord prolapse
Commits you to delivery
Most commonly performed obstetrical procedure

19. Balloon Catheters Foley catheter 30-60 cc
No increased risk of infections
No ‘traction’: may cause trauma, no benefit
Outpatient?
ACOG: reasonable, effective option
Double balloon catheters
More expensive
No more effective per studies

21. Nipple Stimulation More women in labor within 72 hours
Varying protocols
Limited data
Risks
Hyperstimulation
Increase in meconium stained fluid

22. Prostaglandin E2 (FDA approved)
Prepidil
0.5 mg of dinoprostone in 2.5 mL of gel for intracervical administration
Can be repeated in 6 to 12 hours
Maximum cumulative dose of dinoprostone not exceed 1.5 mg (ie, three doses) within a 24 hour period
6 to 12 hours between the final dose and initiation of oxytocin
$75/dose
Cervidil
10 mg of dinoprostone
Timed-release formulation
Administers medication at 0.3 mg/h and should be left in place for 12 hours
Oxytocin may be initiated 30 to 60 minutes after removal of the insert
$150
Can be removed if tachysystole
because of the potential for uterine hyperstimulation with concurrent oxytocin and prostaglandin administration

23. Prostaglandin E1: Misoprostol
Off label use, not FDA approved for OB
Gastric ulcer treatment
100mcg and 200mcg tabs, unscored
Oral vs. vaginal vs. buccal vs. sublingual routes
Oral and vaginal most data
Oral safer
Vaginal slightly faster
Buccal and Sublingual: Limited studies
avoid first pass
higher total bioavailabilty
possibly more tachysystole

24. Misoprostol-Safety Not for VBACS/prior uterine surgery
^ risk of meconium/uterine hyper-stimulation
Safest doses: 25mcg q 3-6 hrs
WHO recommended dose
May reeval and consider increase to 50mcg if ineffective
Monitoring
Outpatient not currently recommended
Indicated for 0.5 to 2 hours
ACOG practice Bulletin No.107
Misoprostol vaginal insert available in Europe
monitoring should be continuous while in hospital setting until further studies

25. Misoprostol-Efficacy
Cochrane Database:
More effective than other prostaglandins for:
Labor induction
Increased cervical ripening
Achieving vaginal delivery in 24 hours
Reduced use of oxytocin augmentation
More effective than oxytocin for labor induction

26. Misoprostol-Dosing Oral administration Intra-vaginally
Peaks sooner and declines more rapidly
25-50mcg q 3-6 hrs
WHO 25mcg q 2 hrs
Less tachysystole
Less effect on FHTs
More comfortable for patient
Intra-vaginally
25-50 mcg every 3-6 hrs
More uterine hyperstimulation
Oxytocin: Minimum 4 hours after last misoprostol dose

27. Qualitative Comparisons of Various Routes of Administration of Misoprostol
Pharmaco-kinetics
Oral
Vaginal
Rectal
Sublingual
Onset
Rapid
Slower
Peak
High
Lower
Highest
Duration
Short
Long
Total
Bioavailabilty
Low
2-3X oral
1.5X oral

28. “The safest method for ripening the cervix and inducing labor appears to be administration of misoprostol orally (25 mcg every 4 hours).” Hofmeyr GJ, Cochrane Database of Systematic Reviews 2017

29. IV Oxytocin Low-dose vs high-dose protocols
40 min to steady state, 5 minute half-life
D5 IV fluids may shorten labor (76 min)?
Optimal 1-2mu/min increased every 30 min
Less tachysystole
Duration of labor equivalent to high or pulsatile dosing
Increased to ‘labor’
normal progression
strong contractions q 2-3 minutes
150 to 350 Montevideo units ( median)

30. Oxytocin per ACOG Continuous monitoring required
Provider within 10 minutes
Order for exceeding 20mu/min needed

31. Elective Inductions: Trends
Not for primes
No electives advised by AWHONN

32. Other labor stimulators/ “partus preparers”
Castor oil
Intercourse
Red raspberry leaf tea
Homeopathy
Acupuncture/acupressure
Evening primrose oil
Mother’s Cordial
Ambulation
Spicy food
Dates

33. Thank you