Induction of Labor International Induction of Labor.

Induction of Labor

International

Induction of Labor

Induction of Labor

International

Objectives

• Definitions

• Indications and contraindications

• Pregnancy dating

• Comparison of methods

• Management considerations

Induction of Labor

International

Induction

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

Induction of Labor

International

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

Induction of Labor

International

Contraindications to Induction

• Any contraindication to labor

Induction of Labor

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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

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Indications - Emergent

• severe gestational hypertension

• suspected acute fetal compromise

• severe IUGR

• significant maternal disease not responding to treatment

• significant APH

• chorioamnionitis

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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

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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)

Induction of Labor

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Indications - NOT

• elective induction- induction, in the absence of maternal or fetal

indication, should not be undertaken

Induction of Labor

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Risks of Induction

• failure to achieve labour

• uterine hyperstimulation with fetal compromise

• uterine hyperstimulation with uterine rupture

• increase risk of C/S

Induction of Labor

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Labour Induction Methods

Likelihood of Successful Vaginal Delivery

LEAST

MOST

LEAST

MOST

favourablecervix

unfavourablecervix

multiparous

nulliparous

previous vaginaldelivery

previous C/S

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

Induction of Labor

International

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)

Induction of Labor

International

Bishop Scoring System

Score

Factor 0 1 2 3

Dilatation (cm) 0 1 - 2 3 - 4 > 5

Effacement (%) 0 - 30 40 - 50 60 - 70 > 80

Consistency Firm Medium Soft

Position Posterior Mid Anterior

StationSp -3 or above

Sp -2 Sp -1 or 0Sp +1 or

lower

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Effect of Cervical Status on C/S Rate

34

20

12

23

13

6

0-3 >3 Spontaneous Labour0

10

20

30

40

50

Ces

area

n S

ecti

on (

%)

Nulliparous Parous

Cervical dilatation at inductionXenakis Obstet Gynecol (1997) 90: 235

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International

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

Induction of Labor

International

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

Induction of Labor

International

Prostaglandin Preparations

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

Induction of Labor

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Prostaglandin E2 • myometrial contraction• cervix

- causes collagen breakdown and proteoglycan deposition

• vasodilator • bronchodilator• GI motility and secretory effects

Induction of Labor

International

Prostaglandin E2 - Route and Dose

• intracervical (Prepidil )

- prostaglandin E2 0.5 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

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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

Induction of Labor

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Prostaglandin E2 - Advantages

• improved patient acceptance

• lower operative delivery rate

• less need for oxytocin induction

• may be used in PROM

• cost considerations

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Prostaglandin E2 - Disadvantages

• adverse reactions- hyperstimulation- CVS events- nausea, vomiting, diarrhea

• gel preparations are difficult to remove

• cost considerations

Induction of Labor

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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

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Labour Induction - Favourable Cervix

Stripping of membranes

Amniotomy

Oxytocin

Vaginal prostaglandins

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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)

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Oxytocin Effects

• myometrial contraction

• cervix - no direct effect

• vasoactive- hypotension possible with bolus IV administration

• antidiuretic activity- water intoxication possible with high dose oxytocin

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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

Induction of Labor

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Uterine Hypertonus

• discontinue oxytocin if in use

• intravenous bolus

• prepare for emergency delivery

• consider tocolytic agents

- ritodrine at 250 - 500 mg/min IV until desired effect

- nitroglycerin 50 mg IV push to maximum of 200 mg

- nitroglycerin spray sublingual

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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

Induction of Labor

International

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

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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

Induction of Labor

International

Induction of Labor

International

Induction of Labor

International

Induction of Labor

International

Induction of Labor

International

Induction of Labor

International