Lecture note

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INDUCTION AND
AUGMENTATION OF LABOR
Moderators:
DR. BUZUNEH
DR. YOHANNES
May,2025

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Presenters
•Abdulaziz Esmael RU2141/13
•Abenezer Eshetu
RU2127/13

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Outline
Objective
Introduction
Definition of induction and augmentation of labor
Indications and contraindications for labor induction
Evaluation before Induction of Labor
Methods of cervical ripening and induction of labor
Complications of induction and augmentation
References

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Objectives
At the end of this presentation you will be able to:
•Define the term induction and augmentation
•Know Indication and contraindication of induction
•Understand way of predicting successful induction
•Know pharmacological and mechanical way of cervical
ripening and induction of labor
•Know both maternal and fetal complications after inducing
or augmenting labor

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DEFINITION
Induction of labor
•Artificial initiation of uterine contractions before the
onset of spontaneous labor to accomplish vaginal
delivery.
Augmentation of labor
•Increasing the frequency and improving the intensity
of existing uterine contractions in a patient who is in
labor and not progressing adequately, in order to
accomplish vaginal delivery.

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Introduction
 One of the most frequently done procedures to
manage labor & delivery.
Done when the benefits of delivery to the fetus or
the mother exceed the benefits of continuing the
pregnancy.

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Undertaken when both of the following criteria
are met :
1. If continuation of the pregnancy is associated with
greater maternal/fetal risk than the risk of
intervention to deliver the pregnancy
2. There is no contraindication to Vaginal birth

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Indications and contraindications for
labor induction
Factors determining indications can be categorized
into :
maternal and fetal conditions
gestational age
cervical status
other factors

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Contraindications to Labor Induction
Absolute
•Prior classic uterine incision or trans fundal uterine
surgery
•Active genital herpes infection
•Placenta or vasa Previa
•Umbilical cord prolapse
•Previous uterine rupture

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•Transverse or oblique fetal lie, footling breech
presentation
•Absolute cephalopelvic disproportion (pelvic
deformities)
•Category 3 fetal heart rate tracing

12. Relative contraindications
•Cervical carcinoma
•Mal presentation (breech)
•One previous low-transverse cesarean delivery
•Multi fetal pregnancy
•Extreme prematurity
•Macrosomia
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Evaluation before induction of labor

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Elective induction of labor
•Elective induction of labor refers to the initiation of
labor for convenience in an individual with a term
pregnancy who is free of medical or obstetric
indications

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•Although elective induction at or after 39 weeks of
gestation is not recommended, it may be appropriate in:
women with a history of very short labors
who live a great distance from the hospital
who has experienced a prior stillbirth at or near term
to ease anxiety and fears about the loss of a
subsequent pregnancy
when a fetal anomaly is present.

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Prediction of labor induction success
characteristics associated with successful induction
include:
•Multiparty
•Tall stature (over 5 feet 5inches)
•Increasing gestational age
•Non obese maternal weight or body mass index
•Infant birth weight less than 3.5 kg
•Elevated fetal fibronectin (fFN) concentration in
cervicovaginal secretions
•Sonographically measured short cervical length

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•Cervical status is one of the most important factors for
predicting successful induction of labor
•The modified Bishop score syste is most commonly
used in clinical practice to evaluate the cervix prior to
induction.
- It tabulates a score based upon the station of the
presenting part and four characteristics of the cervix:
dilatation, effacement, consistency, and position

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Interpretation:
• Score ≤ 4 is unfavorable or unripened
• Score 5-8 is intermediate
• Score≥ 9 is favorable

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Requirements For Cervical Ripening And
Induction Of Labor
a) Personnel familiar with the effects of uterine
stimulants on the mother and fetus because uterine
hyper stimulation may occur with induction of labor.
b) Monitoring fetal heart rate and uterine contractions
is recommended as for any high-risk patient in
active labor.
c) A physician capable of performing a cesarean
delivery should be readily available.

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Labor induction is primarily conducted by using
amniotomy, prostaglandins, and oxytocin, each alone
or in combination
Methods of cervical induction

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1. Prostaglandins
• PGs are endogenous compounds found in the
myometrium, deciduas, and fetal membranes during
pregnancy
• Side effects: chills, fever, vomiting, diarrhea
• Contraindications: renal and liver dysfunctions, asthma

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PGE2 (Dinoprostone)
a. 0.5 mg in 2.5 ml gel (prepidil)
Intracervical
Q 6 – 12 hrs
Max. 1.5 mg/24 hrs till Cx ripening
Induction 6 – 12 hrs after last dose
b. 10 mg vaginal insert (Cervidil)
Timed release (0.3 mg/hr)
Leave in place for 12 hrs
Induction with oxytocin 30 – 60’ after
removal

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Prostaglandin E1
Misoprostol (cytotec)
Both vaginal and oral misoprostol are used for
either cervical ripening or labor induction.
Synthetic prostaglandin E1 analog available as
100 mcg and 200 mcg tablets
25 mcg, intra-vaginal into posterior fornix
Q 3 – 6 hrs till the Cervix becomes favorable
Induction 4 hrs after the last dose

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2.Synthetic oxytocin
Oxytocin is a polypeptide hormone produced in the
hypothalamus and secreted from the posterior lobe of the
pituitary gland in a pulsatile fashion
Synthetic oxytocin an effective means of labor induction
Effect first demonstrable from 20 wks onwards
Given intravenously/intramuscularly
The plasma half life estimated at 3 to 6 minutes
Steady-state concentrations reached within 30 to 40 minutes
of initiation
Dilution: 10 IU in 1000ml of isotonic IV fluid; 10mu/ml &
given by infusion pump or drip form

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3. Amniotomy
Elective amniotomy with the intention of accelerating
labor is often performed.
Amniotomy at approximately 5-cm dilation accelerated
spontaneous labor by 1 to 1½ hours.
Amniotomy is associated with a risk of cord prolapse.
To minimize this risk, disengagement of the fetal head
during amniotomy is avoided and
Fundal or suprapubic pressure or both may be helpful.

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Care during induction of labor
Informed consent by the woman
reasons for induction
choice of method to be used
potential risks and consequences of accepting or declining
an offer of induction of labor.
Oxytocin infusion is discontinued whenever hyperstimulation
or fetal distress is identified but can be restarted when
reassuring fetal heart rate and uterine activity patterns are
restored.

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Cont.
Place of induction
should occur on a delivery suite
continuous electronic monitoring of both FHR and uterine
activity
Women receiving oxytocin for induction of labor should
receive one-to-one follow up care.
Following instillation of prostaglandin agents, the woman
should be advised to lie down for at least 30 minutes

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Cont.
Fetal surveillance
continuous uterine and FHR monitoring
Fetal wellbeing should be established immediately prior to
induction of labor.
FHR and uterine activity should be monitored continuously
for a period of 30 minutes to 2 hours after administration of
the PGE2
FHR monitoring continued if regular uterine contractions
persist;
Where oxytocin is being used for induction labor,
continuous electronic fetal monitoring should be used.

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Complications of induction
Maternal
 Failed induction
 Uterine hyperstimulation contractions
 Chorioamnionitis
 Placental abruption
 Water intoxication/hyponatremia
 Hypotension
 PPH
 Uterine rupture

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Uterine over activity
• Uterine tachysystole is defined as 6 contractions in a 10-
minutes in consecutive 10-minute intervals
• Uterine hypertonus is described as a single contraction lasting
longer than 2 minutes in a 10-minute period
• Uterine hyperstimulation is when either condition leads to a
nonreassuring fetal heart rate pattern
• Non reassuring : demonstrated by late deceleration, or fetal
bradycardia
Concurrent administration of oxytocin and a prostaglandin
increase the risk of tachysystole

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Failed induction
• There are various ways to define failed induction but it is
important to allow adequate time for cervical ripening and
development of an active labor pattern before determining
that an induction has failed.
• The inability to achieve cervical dilatation of 4 cm and 80%
effacement or 5 cm (regardless of effacement) after a
minimum of 12 to 18 hours of both oxytocin administration
and membrane rupture.
• Uterine contractions should reach 5 in 10 minutes or 250
Montevideo units, which is the minimum level achieved by
most women whose labor is progressing normally.

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Complications of induction
Fetal
 Iatrogenic Prematurity
 Fetal asphyxia
 Cord prolapse
 Neonatal sepsis

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References
•Williams obstetrics 26th edition
•Current Diagnosis & Treatment Obstetrics &
Gynecology 11th Edition
•Steven_G._Gabbe_et_al. Obstetrics Normal and
Problem Pregnancies(9th
edition)

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