Induction of Labou23rd Obstetrical Update for Family Physicia

October 28, 20

Dr. Michele LiObstetrician/Gynecolog

Lion’s Gate HospiNorth Vancouv

Definition

The iatrogenic stimulation of uterine contractions prior to the onset of spontaneous labour

Benefits and Risks

IOL indicated if both conditions met:continuing pregnancy is believed to bassociated with greater maternal or fetal risk than intervention to deliver the pregnancyno contraindication to vaginal birth

Balance

severe preec

PPROM

IUGR

oligohydram

macrosomia

y of poor enatal tcomeuncomplicated

estational diabetes

tain dates

Pre-Induction Assessment

determine indicationreview pregnancy and medical historyreview process with patient

Prerequisites/Documentation

indication for induction

any contraindications

gestational age

cervical favourability*

fetal presentation

potential for cephalopelvic disproportion

The Importance of the Bishop

Bishop Score: system to score the cervi

Predictive of outcome of induction

0 1 2 3Dilation closed 1-2 3-4 5-6

ffacement (%) 0-30 40-50 60-70 ≥80Station -3 -2 -1, 0 +1, +2

Consistency Firm Medium SoftPosition Posterior Mid Anterior

Modalities

natural

mechanical

medical

Data from Perinatal Services BC

Indications for Induction

Post-term, > 41 weeks 35%

Maternal disease 25%

PROM 19%

Other/unknown 12%

Evidence of fetal compromise 7%

Fetal demise 1%

Logistics 1%

Duration of induction

No defined duration for cervical ripeningProstaglandin dosing

gel: every 6 - 12 hours for 3 dosesinsert:

additional doses have been used in somstudies

Term PROM

Term Prom trial supports immediate inductionWomen colonized with GBS should consider immediate induction with oxytocin

Post-Dates

accurate dating requiredfirst trimester ultrasound

rationale for inductionprevention of stillbirth

Post-Dates

Maternal age dependentincrease in rate of stillbirth associatewith maternal age > 40 once at 400

weeks

Over 40 Years Old

Effects of coexisting medical conditionsHigher prevalence of placental problemIncreased risk of low birthweight and preterm deliveryIncreased risk of stillbirthIncreased risk of Ceasarean delivery

Gestational Diabetes

GDM associated with increased pre-eclampsia risk and macrosomiaend of pregnancy care determined by need for insulin to control blood sugars

Diet Controlled GDM

no increased risk of stillbirthno requirement for antenatal fetal surveillance or early induction of labou

Insulin Requiring GDM

Higher risk of adverse perinatal outcomInduction benefits include:

prevention of late stillbirthavoidance of delivery-related complications of continued fetal growth

Insulin Requiring GDM

Risks of induction: Ceasarean delivery for failed inductiontachysystoleiatrogenic prematurity

Insulin Requiring GDM

Induction at 38 weeks:fewer LGA infantsfewer cases of shoulder dystocialower C/S rate

nduction for Women with GDM

Diet control: deliver as per standard obstetrical indicationsInsulin requiring:

induce at 39 weeksconsider induction at 38 weeks if glycemic control suboptimal

Hypertension

‘Planned delivery on the best day in the best way’

Pre-existing Hypertension

Increased risks for pregnancy:superimposed preeclampsiaabruptio placentaePreterm birthFetal Growth Restriction

Gestational Hypertension

Mild disease should be delivered by 40 weeks gestationConsider earlier delivery for routine obstetrical indications

Preeclampsia

Consider immediate delivery for milddisease at ≥ 370 weeks gestation