This document discusses induction and augmentation of labor. It begins by defining induction of labor as artificially stimulating uterine contractions before the onset of labor, while augmentation refers to stimulating inadequate spontaneous contractions. The document then covers the structures and physiology of the cervix as it relates to ripening. It discusses various methods of assessing cervical status including Bishop's score and indications, contraindications, risks and prerequisites for labor induction. The document provides an overview of common methods used for cervical ripening and labor induction.

1. INDUCTION AND
AUGMENTATION OF
LABOUR
PRESENTED BY : Prof. M.C.Bansal
MBBS., MS., FICOG., MICOG.
Founder Principal & Controller,
Jhalawar Medical College & Hospital Jjalawar.
MGMC & Hospital , sitapura ., Jaipur

2. INTRODUCTION
•The culmination of normal pregnancy involves three stages: prelabour,
cervical ripening and labour.
•Endogenous prostaglandins play a part in all these processes.
•Interventions to artificially ripen the cervix, induce uterine contractions and
augment labour once it is in progress also lack distinct boundaries.
•Labour induction and augmentation may be a source of conflict and
distress.
•For most health workers they are seen as routine, technical procedures.

3. INTRODUCTION
•For many women, they have emotive connotations, evoking a sense of personal
inadequacy and eroded self-esteem.
•It is important for health workers to approach the question of labour induction
with sensitivity, and to involve women in the decision-making process.
•Labour induction is one of the most frequent medical procedures in pregnant
women.
•It is a major intervention in the normal course of pregnancy, with the potential to
set in motion a cascade of interventions, particularly Caesarean section.
•However, with modern methods of labour induction, this risk appears to have
diminished.

4. Definition:
Induction of Labor (IOL) is defined as artificial
stimulation of uterine contractions before the
onset of labor.
Augmentation refers to stimulation of
spontaneous contractions that are considered
inadequate because of failed cervical dilation
and fetal descent.

5. The goal of IOL is to eliminate the potential
risks to the fetus with prolonged intrauterine
existence while minimizing the likelihood of
operative delivery
The overall incidence of IOL has increased
globally. In a survey by the National Center for
Health Statistics the rate of labor induction
was noted to have increased from 90 per
1,000 live births in 1989 to 184 per 1,000 live
births in 1997 (1).

6. Indications For induction:
•Hypertensive disorders of pregnancy ( pre-eclampsia, eclampsia,
chronic hypertension)
•Diabetes, renal disease, chronic pulmonary disease
•Premature rupture of membranes
•Chorioamnionitis
•Fetal growth restriction
•Rh isoimmunization
•Postdated pregnancy
•Fetal demise
•Abruptio placentae
•Fetal malformations incompatible with life
•Logistic factors: Risk of rapid labor, distance from hospital, psychosocial
indications

7. Contraindications to the induction of labor:
•Major degree of Placenta praevia
•Vasa praevia
•Previous classical uterine incision or incision because
of metroplasty or extensive myomectomy when the
cavity is opened
•Cephalopelvic disproportion because of
malpresentation or abnormal pelvic bone structure
•Active genital Herpes infection
•Invasive cervical carcinoma
•Hypersensitivity to cervical ripening agents
Transverse lie

8. Conditions where IOL is not a true contraindication
but where special caution is required :
•Multiple pregnancy
•Polyhydramnios
•Grand multiparity
•Maternal heart disease.
•Severe hypertension.
• Breech presentation
•One or more previous cesarean section
•Abnormal fetal heart rate not requiring emergency
cesarean section

9. Risks of IOL:
Maternal Risks :
•Failure leading to Cesarean section
•Uterine hyperstimulation
•Rupture uterus
•Intrauterine infection, Chorioamnionitis
•Amniotic Fluid Embolism
•Precipitate labor , Dysfunctional labor
•Increased risk of operative vaginal delivery
•Increased risk of post partum hemorrhage
•Abruptio Placentae
•APH from undiagnosed placenta praevia
•Water intoxication

10. Fetal Risks :
•Fetal distress .
•Fetal death
•Neonatal sepsis
•Iatrogenic delivery of a preterm infant
•Cord prolapse
•Neonatal jaundice
•Increased risk of birth trauma

11. Pre- requisites for IOL:
•Evaluate the indication
•Explain the indication of induction to the patient along with details of
the method to be used and take a written informed consent
•Assess adequacy of the pelvis and fetal size
•Confirm the gestational age, fetal lie, and assess the fetal lung maturity
# where ever indicated
Uterine activity and fetal heart rate should be continuously monitored.
In case of clinical auscultation, FHR should be heard during and for 30
seconds after a contraction at least every 15 minutes during the active
phase of labor and after every contraction in the second stage .
Otherwise electronic fetal monitoring is preferable
· Partogram is to be maintained for active labour
· Trained personnel and well equipped center

12. # According to the ACOG Committee Opinion (2) , if one of the following
criteria are met then fetal maturity may be assumed and amniocentesis
need not be performed to confirm fetal maturity:
- Fetal heart tones have been documented for 20 weeks by non electric
fetoscope or for 30 weeks by Doppler
- It has been 36 weeks since a positive serum or urine human chorionic
gonadotropin pregnancy test was performed by a reliable method
- An ultrasound measurement of the crown rump length, obtained at 6-
11 weeks,
supports a gestational age of 39 weeks or more
- An ultrasound scan obtained at 12 to 20 weeks confirms the
gestational age of 39 weeks or more determined by clinical history and
physical examination

13. Structures of the cervix and Physiology of cervical ripening :
The uterine cervix has broadly two components which are:
a) cellular portion and,
b) extracellular matrix
The distal portion has greater connective tissue as compared to the part
close to the myometrium which is richer in the cellular component.
The cellular component has: smooth muscle cells, fibroblasts,
epithelium, and blood vessels. Cervical stromal cells produce
collagenases, elastases and metalloproteinaeses which are involved in
remodeling of the cervix. Fibroblasts also secrete cytokines like
interleukin 1 beta and interleukin -8

14. Extracellular matrix is composed of :
a) Collagen: collagen is in two forms Type I (70%) and type II
(30%) and is arranged in the form of a triple helix. In the non
pregnant cervix these are arranged in a dense and irregular
fashion
b) Elastin: these fibres are arranged parallel to and between
the collageAn fibres and play an important role in taking the
pregnancy to term by keeping the os closed
c) Decorin: is a glycosaminoglycan and its relative proportion
to collagen is important in the remodeling of the cervix at
labor
d) Hyaluronic acid: is the most important proteoglycan which
is responsible for the increased water content of the cervix

15. Changes during pregnancy:
a) Collagen is reorganized and consolidated in early pregnancy with
proliferation and hyperplasia of the cellular component
b) Near the onset of labor, an overall decrease in the concentration
of collagen occurs with dispersion and remodeling into fine fibres ,
making the cervix softer in consistency
c) Increases in decorin levels and physiologic cell death are in part
responsible for this process
d) Hyaluronic acid levels increase thereby increasing the water
content of the cervix and causes a loosening and dispersal of the fibres
e) Chemotactic response at term leads to an influx of neutrophils
and an increased levels of cyokines (interleukin 1 beta and interleukin –
8 ) which in turn release collagenases and elastases to allow effacement
f) Mechanical forces of uterine contractions extend the elastin and
allow dilatation

16. PRE INDUCTION CERVICAL ASSESSMENT:
It is known that success of labor induction is closely related to
ripeness of the cervix . Various scores have been proposed to
evaluate the cervical status.
a) Bishop’s Score : This was proposed by Bishop in 1964 (3)
and is the most widely used score. It was originally proposed
to determine the suitability of a patient for IOL in patients
who were parous, at term , had an uncomplicated pregnancy
and the fetus was in cephalic presentation.

17. Table 1. Bishop Score for Assessing Favor ability for Induction of labour.
Score
Factor 0 1 2 3
Dilatation (cm) 0 1-2 3-4 5-6
Effacement(%) 0-30 40-50 60-70 80
Station -3 -2 -1 or 0 +1 or +2
Consistency Firm Medium Soft -
Position Posterior Mid Anterior -
* A score of 9 or more ensured a safe and uniformly successful induction

18. * Induction with a score of 16 more is considered
favorable
Burnett (5) later on modified the original Bishop’s
score giving a maximum score of 2 to each of
Bishop's five categories, giving a total maximum
score of 10.
He considered effacement in terms of length and
not percentage and considered previous term birth
and cephalic presentation to be pre-requisites for
induction.

19. * Outcome of patients with a score of less than 6 was unfavorable, with a score of 9-
10 all patients could be delivered within 4 hours and most within 24 hours.
Evaluating the performance of Bishop's score, Lange et al (6) observed that cervical
dilatation was twice as important as the other factors and proposed a modification of
the original score which predicted successful induction equally well.

20. Table 4. Pelvic Score Proposed by Lange et al
Score
Factor 0 1 2 3 Multiply by
Dilatation (cm) 0 1-2 3-4 >4 X2
Length (cm) 3 2 1 0 X1
Station(cm) -3 -2 -1 or 0 +1 or +2 X1

21. METHODS OF CERVICAL RIPENING AND LABOR
INDUCTION: Cervical priming before labor induction
in an unfavorable cervix increases the success rates
and shortens the induction to delivery interval.
Methods for cervical ripening and labor induction can
be broadly classified as :
•Pharmacological methods (Prostaglandins, Oxytocin
& others)
•Non pharmacological methods (Natural, Surgical ,
Mechanical and others)

22. PHARMACOLOGICAL METHODS
PROSTAGLANDINS :
PG E2 gel has been widely used for pre-induction
cervical ripening. Local applications of PGE2 causes
cervical ripening by three mechanisms:
•Alteration of extracellular grounds substance of
cervix by increasing collagenase , elastase,
glycosaminoglycans , dermatan sulfate, and
hyaluronic acid levels
•Relaxation of smooth muscle of cervix
•Gap junction formation leading to initiation of
uterine contractions

23. Preparations available, Dosage and Usage Guidelines :
Intracervical PGE2 gel: ( Cervigel , Dinoripe , Prepidil )
•Contains 0.5 mg of PGE2
•Bring the gel to room temperature before use and instill in
the cervical canal below the internal os
•The patient lies supine for 15-30 minutes after the insertion .
•If no response occurs in one use a repeat insertion may be
required after 6 hours
•Maximum of 1.5 mg or three insertions are allowed over a
period of 24 hours.
•If required oxytocin is to used only after 6- 12 hours of the
last insertion.

24. Intravaginal PGE2 gel:
•Vaginal PG E2 gel : - contains 2.5 mg PGE2
- 2 doses 6 hours apart are used
•Vaginal controlled release insert : (Cervidil )
- 10 mg insert which releases 0.3 mg / hr of the
prostaglandin
- No need to pre warm the insert .
- The patient should lie supine for 2 hours
following the insertion
- The insert is to be removed after 12 hours or
when active labor begins or in case of
hyperstimulation.

26. PGE 2 Routes : Controlled trials : Some observations (10-13)
•Intracervical use is technically more difficult
•Vaginal route ( gel or insert ) is superior to intracervical route for
cervical ripening but it causes higher uterine activity
•Controlled release vaginal insert use gives a better post ripening score,
decreased the time to delivery, time to active labor and need for
oxytocin use as compared to vaginal gel 2 doses 2.5 mg six hours apart.
•The overall incidence of hyperstimulation is 4.8% - same as with
oxytocin. However , the incidence is more when used in active labor
(12.5 %) , more with vaginal gel (5%) than intracervical (1%) and least
with controlled release insert which can be reversed with terbutaline
administration or removal of the vaginal insert. Washing the vagina does
not offer any benefit .
•Use of PGE 2 does not alter C. S. rates

27. Contraindications:
Established uterine activity, glaucoma, asthma,
severe hepatic or renal impairment , known
hypersensitivity to prostaglandins , active
vaginal bleeding

28. Side Effects
Uterine tachysystole has been reported to follow vaginally administered
prostaglandin E2 in 1 to 5 percent of women . Although definitions may vary
among studies, most use the terms defined by the American College of
Obstetricians and Gynecologists (1999a) to describe increased uterine activity
as follows:
1.Uterine tachysystole is defined as 6 contractions in a 10-minute period.
2.Uterine hypertonus is described as a single contraction lasting longer than 2
minutes.
3.Uterine hyperstimulation is when either condition leads to a nonreassuring
fetal heart rate pattern.
Because hyperstimulation that can cause fetal compromise may develop when
prostaglandins are used with preexisting spontaneous labor, such use is not
recommended. If hyperstimulation occurs with the 10-mg insert, its removal by
pulling on the tail of the surrounding net sac will usually reverse this effect.
Irrigation to remove the gel preparation has not been helpful.

29. ACOG Guidelines : (14,15)
Bishop’s score should be less than 4. Drug should be
administered near the delivery suite. Patient should lie
recumbent for 30 minutes after the instillation. FHR and
uterine activity should be monitored for 30 minutes to 2
hours after the instillation. After this , patient may be
transferred elsewhere, if there is no increase in uterine
activity and FHR is normal. The controlled release insert
should be removed at the onset of labor. Oxytocin should be
avoided for initial 6-12 hours

30. RCOG Guidelines : (16)
Intravaginal PGE2 should be used in preference to
intracervical preparations as they are equally effective
and administration of intravaginal PGE 2 is less
invasive of the vaginal preparations. Tablets should be
preferred over the gel as they are more cheap and
equally effective.

31. MISOPROSTOL:
Mioprostol is a synthetic PG E1 analogue which has
been used as a gastric cytoprotective agent since
1988 for patients of peptic ulcer.
Studies in late 1980’s and early 1990’s noted that oral
administration of this drug causes uterine
contractions in early pregnancy. Subsequent studies
showed that intravaginal misoprostol causes first and
second trimester abortion and there has been recent
evidence of its use for cervical ripening and labor
induction.

32. Pharmacokinetics: The pharmacokinetics of misoprostol
have been extensively studied by Ziemann et
al (17). They have observed that peak plasma concentration is
higher and achieved earlier after an oral administration. Peak
levels with vaginal administration are attained more slowly
and sustained for longer periods because of the presystemic
gastrointestinal and hepatic metabolism that occurs with oral
route . Overall the systemic bioavailability is three times higher
with the vaginal route.

33. Dosage schedules and usage guidelines:
•Cheap drug
•Does not require storage conditions
•Can be given by oral, buccal or vaginal routes
although vaginal route is the most extensively used
•Tablets are available as either 100 mcg or 200 mcg
•Dosage: 25 –50 mcg is administered 4-6 hourly
•The tablet is inserted into the posterior vaginal
fornix , one may or may not wet the tablet with saline
prior to insertion

34. Misoprostol : Controlled trials : some observations: (18)
•Oral route is not recommended at this point of time
•Misoprostol shortens the Induction delivery interval as
compared to PG E2 and oxytocin
•25 mcg vaginal dose has less hyperstimulation but a longer
IDI as compared to 50 mcg
•It effectively lowers the cesarean rates
•However it is not recommended as an outpatient setting or
with previous C. S.
•An increase in the incidence of meconium staining of amiotic
fliud and tachysystole is noted
•Overall the use of misoprostol is not associated with an
increased rate of operative intervention for fetal distress and
NICU admission.

35. ACOG Guidelines
25mcg should be the initial dose for labor induction at term , should not
be administered more frequent than 3-6 hours , oxytocin should not be
administered < 4 hours after the last misoprostol use and the drug
should be avoided in patients with previous cesarean delivery or major
uterine surgery.
Use of higher dosage 50 mcg may be appropriate in some situations
and have a greater likelihood of vaginal delivery within 12 hours, such
doses increase the risk of hyperstimulation and rupture.
There is at present insufficient clinical evidence to address the safety of
misoprostol in patients with multiple gestations and suspected fetal
macrosomia.

36. RCOG Guidelines : (16)
Misoprostol appears to be more effective than oxytocin or vaginal PG E2
in presence of ruptured membranes for induction of labor.
Use of misoprostol in obstetrics must be restricted to RCTs.
Oral misoprostol appears to be less effective than vaginal misoprostol,
however, oral route is associated with less incidence of uterine
hypercontractility but a higher incidence of meconium stained liquor.
Its use is associated with increased uterine hypercontractilty but this is
not translated in increased operative delivery rates. The safety issues
surrounding the use of misoprostol have not been clearly evaluated.
* Despite a lot of clinical use, misoprostol is still not approved by the
Drug Controller of India for use in induction of labor.

37. OXYTOCIN:
Oxytocin is a polypeptide hormone secreted from the
posterior pituitary gland which acts as a potent uterotonic
agent. The drug was used intravenously in 1948 by Theobald
et al (21) to induce labor. Later in 1958 Du Vigneaud et al (22)
synthesized the drug. Since then it has been the most
commonly used drug for induction and augmentation of
labor.
Routes of administration:
Oxytocin can be administered by any parenteral route,
intravenous route being the most widely used. It can be
absorbed from the nasal or buccal mucosa, however when
given orally it is rapidly inactivated by trypsin.

38. Pharmacokinetics and mechanism of action:
The half life of oxytocin is 3-5 minutes. Once absorbed it is distributed in the
extracellular fluid and does not bind to plasma proteins and is excreted by the liver
and kidneys.
The action is mediated by oxytocin receptors (OTR) which are present on the
myometrium.
Myometrial response to oxytocin begins at 20 weeks , increases through out
pregnancy and peaks just before initiation of labor.
The response varies according to the status of the cervix, uterine sensitivity, variability
in oxytocin clearance rate, duration of pregnancy and the pre-existing myometrial
contractions.
The OTR concentration is the rate limiting step for oxytocin action. Oxytocin on
binding to the OTR increases the intracellular concentration of calcium causing
myometrial cell contraction. Uterine contractions are also stimulated by a calcium
independent mechanism involving the prostaglandins. PGE and PGF are increased
during oxytocin administration. It has been postulated that Prostaglandin release by
oxytocin is necessary for fully efficient uterine contractions during labor.

39. Dosing and Usage Guidelines:
10 –20 units are dissolved in 1000 ml of balanced salt solution ( Ringer Lactate solution
or Normal saline ) making it as 10-20 mu/ml and it is preferable to give it through an
infusion pump. Further increments are made according to the low dose or high dose
protocol given below (15 ) :
Regimen Starting dose Incremental dose Dosage interval
(mU/ min) (mU/ min) ( min)
Low Dose 0.5 – 1 1 30-40
1 –2 2 15
High dose 6 6 15
6 6, 3*, 1* 20-40
* The incremental increase is reduced to 3 mU/min in presence of hyperstimulation
and reduced to 1mU/min with recurrent hyperstimulation .

40. After intravenous infusion , uterine response occurs within 3-
5 minutes and a steady state plasma concentration is reached
in about 40 minutes.
The end point to be achieved is uterine contractions every 2-
3 minutes lasting for 60-90 seconds and a uterine pressure of
50- 60 mm Hg or 150 Montevideo units.

41. Risks of Oxytocin:
· Hyperstimulation , with or without fetal heart rate
changes
· Failed induction with need for repeat induction or
possibly cesarean
· Increased risk for uterine rupture in some studies
· Hypotension if administered by IV bolus
· Hyponatremia if administered with large amounts of
sodium poor fluids
· Antidiuretic hormone like effect if administered at high
doses
· Increased risk for neonatal hyperbilirubinemia

42. In the management of active-phase arrest, and with
no contraindication to intravenous oxytocin,
decisions must be made with knowledge of the safe
upper range of uterine activity.
Importantly, despite no labor progression, there
were no adverse maternal or perinatal effects in
those undergoing cesarean delivery.
There are no data regarding safety and efficacy of
contraction patterns in women with a prior cesarean
delivery, with twins, or with an overdistended uterus.

43. Duration of Oxytocin
Administration—Active Phase
Arrest
First-stage arrest of labor is defined by the American
College of Obstetricians and Gynecologists (1989,
1995a) as a completed latent phase along with
contractions exceeding 200 Montevideo units for
more than 2 hours without cervical change. Some
investigators have attempted to define a more
accurate duration for active-phase arrest.

44. Rouse and colleagues (1999) prospectively managed 542
women at term with active-phase arrest and no other
complications.
Their protocol was to achieve a sustained pattern of at
least 200 Montevideo units for a minimum of 4 hours.
This time frame was extended to 6 hours if activity of 200
Montevideo units or greater could not be sustained.
Almost 92 percent of these women were delivered
vaginally.
These and other studies support the practice to allow an
active-phase arrest of 4 hours (Rouse and associates,
2001).

45. How do we calculate uterine
activity ?
MONTEVIDEO UNITS :
No of contractions / 10 MIN
X
Avg, intensity of contractions in mm of hg
Eg : 3 X 60mmHg = 180
Uterine activity – Spontaneous labour - 200 MVs
Induction of labour - 250 – 275
MVs

46. RCOG Guidelines : (16)
· Oxytocin should not be started for 6 hours following
administration of vaginal prostaglandins
· In women with intact membranes , if feasible
amniotomy should be performed prior to commencement of
oxytocin infusion
· Minimum possible dose of oxytocin should be used and
titrated against uterine contractions. Maximum licensed dose
is 20 mU/min and should not be exceed 32 mU/min
· Local protocols should specify the dose , dilution of
oxytocin and preferably be delivered via infusion pump or
syringe driver with non-return valve

48. Infusion pumps is an electronic apparatus designed to
deliver drugs and 'biologicals', at low doses.
The delivery process of these pumps are associated with
local hemolysis which consists the potential benefits of a
calibrated delivery system.
infusion pumps are easy to use as these are designed
keeping in mind the requirements of patrons at our
vendors' end.

49. Oxytocin Administration via the Infusion Pump
1. Oxytocin for the purpose of induction or augmentation of labor, will be ordered by the
physician and administered by an RN.
2. Oxytocin administered for induction or augmentation of labor will be performed only in
L&D after a minimum 30 minute baseline FHR and UA tracing is obtained.
3. A registered nurse is responsible for the operation of the pump (adjustments to infusion
rate per MD order).
4. Continuation of an oxytocin infusion beyond 20 milliunits/min requires an MD order.
5. In accordance with ACOG recommendations, the practice of elective* delivery prior to
39 weeks gestation is prohibited (unless approved by Chairman/Clinical Chief).
*An elective delivery is a delivery prior to 39 weeks gestation without a valid medical or

50. CONTRA-INDICATIONS:
Contraindications include but are not restricted to:
1. Unfavorable fetal positions
2. Uterine tachysystole
3. Hypersensitivity to the drug
4. Cases where vaginal delivery is contraindicated, such as
complete placenta previa, vasa previa, and cord prolapse

51. EQUIPMENT:
Infusion pump
Premixed 500ml bag of D5W with 20
units of oxytocin
Infusion pump tubing

52. PROCEDURE:
ACTION
1. Place patient on external electronic fetal monitor to establish a continuous fetal
heart rate (FHR) tracing and uterine activity (UA) pattern.
2. The determination of cervical dilation, effacement, station and position should be
performed either prior to the initiation of the infusion or within the first 2 hours
after the initiation of the infusion.
3. Assist with the placement of internal fetal monitoring and intrauterine pressure
catheters when ordered by
3. Provide additional information regarding fetal status and uterine contractions.

53. 4. Piggyback oxytocin infusion to main IV line as close to venipunture as possible. It may be necessary to remove or add
different IV tubing so the oxytocin can be placed close to the venipuncture site.
4. Piggybacking the solution away from the venipuncture site can result in an oxytocin bolus.
5. Program infusion pump. Select Intrapartum pitocin concentration (20 units oxytocin in 500 ml)
6. Confirm pitocin concentration.
6. Concentration is 40 milliunits/ml.
7. Select dose in milliunits/min.
8. Enter the volume to be infused.
9. Begin infusion at 2 milliunits/min and increase by 2 milliunits/min every 30 minutes or as ordered by the physician until an
adequate labor pattern is established. When the infusion rate reaches 20 milliunits/min notify the physician.
9. Continuation of the infusion beyond 20 milliunits/min requires a physician’s order.

54. 10. Decrease oxytocin if:
Tachysystole is present
The uterine resting tone is increased by palpation assessment or Intrauterine Pressure Catheter
(IUPC)
For fetal heart rate tracing concerns as assessed by nurse or physician. MD should be notified.
11. Discontinue oxytocin if:
Uterine tetany
Fetal indications as assessed by nurse or physician
10. Notify physician.
12. If restarting oxytocin is indicated, begin with the following guidelines:
If the oxytocin was discontinued for less than 30 minutes because of:
Uterine tachysystole restart oxytocin 4 milliunits/min lower than the previous level

55. Fetal indications: restart oxytocin at 2.0 milliunits/min or at the
discretion of the physician
If the oxytocin discontinued for more than 30 minutes, restart at 2.0
milliunits/min or at the discretion of the physician

56. Other Pharmacological methods:
a) Mifepristone: 200 mg misoprostone for 2 days has been recently used for
cervical priming (23). However this method is not cost effective and needs further
trials.
b) Relaxin : Relaxin has been demonstrated to causes changes in the collagen
resulting in cervical softening . Both purified porcine and DNA produced human relaxin
have been tried with success in promoting cervical ripening with no adverse maternal
and fetal outcomes (24,25) . It is not yet commercially available.
c) Nitric Oxide: Animal studies have shown it to be a cervical ripening agent but it is
unlikely to be used for human use unless safety of NO in late pregnancy is established
d) Cytokines: Theses are chemotactic agents which also can promote cervical
ripening by causing changes in the extracelllulaar matrix

58. NATURAL MODALITIES:
a) Herbal supplements: Commonly used herbal cervical ripening
agents include evening primrose oil, black cohosh, raspberry leaves. The
liquid of black cohosh is given as 10 drops sublingually hourly until the
cervical change occurs. Evening primrose oil is given as 3 capsules orally
daily for one week, this can be repeated for three such administrations..
red raspberry leaves also enhance uterine contractions in a synchronous
manner
b) Intercourse : results in a 10-50 fold increase in cervical mucus
prostaglandin concentrationswhich occurs after 2-4 hours and remains
for more than 12 hours duration . There is an associated increase in
the uterine contractile activity .

59. SURGICAL METHODS:
AMNIOTOMY: Ideally amniotomy or ARM is performed when the cervix is effaced
and 2 cm dilated but it can be performed with minimal cervical dilatation.
Methodology of ARM:
•Auscultate the FHR
•Evaluate the cervix and station of head. The cervix should be well applied to the head
•Introduce two fingers into the cervix , sweep away the membranes from the cervix
•Pass an Allis or Kocher’s forceps in between the groove of your two fingers , hook the
membranes and rupture them ; look for the clarity of liquor
•Risks: Cord prolapse
FHR deceleration
Bleeding through vasa praevia
Fetal injury
Maternal and fetal infection
Advantages: - It shortens duration of labor
- Allows for early diagnosis of meconium staining of amniotic fluid,specially
in high risk pregnancy
- Facilitates invasive fetal monitoring

60. MECHANICAL MODALITIES:
a) Hygroscopic dilators: These are natural or synthetic rods inserted
through the cervical os and left in situ for a particular time wherein
because of their osmotic properties they absorb endocervical and local
tissue fluids . This swelling causes a controlled dilatation of the cervix
along with releasing prostaglandins. Natural dilators are obtained from
the seaweed Laminaria japonicum.
b) Balloon devices : Foley’s catheter or designer balloon devices
when inserted intracervically can facilitate cervical ripening. Once
properly placed ( beyond the internal os) balloon or the catheter is
inflated with 30-50 ml saline. It is recommended to either attach a
defined weight to the catheter end ( 1litre of i.v. fliud ) or to use “gentle
tugs” – 2 to 4 each hour until the catheter or the balloon passes out
(26,27) . Some recommend infusion of extra-amniotic saline at the rate
of 1 cc/minute. There is no infection associated with balloon devices

61. Mechanical -- Double balloon

62. MISCELLANEOUS:
a) Castor Oil (28 ) : It is an extract from “Ricinus communis”
and is mainly crude ricinoleic acid .It is known to stimulate gut
peristalsis and labor most likely is stimulated due to release of
prostaglandins. The method is no longer used now. One study
has reported an increased incidence of meconium staining of
amniotic fluid.
b) Accupuncture and TENS( Transcutaneous electric nerve
stimulation) : Few studies ( 29-31) have reported successful
induction of labor with these methods but further trials are
needed before planning a large scale use.

63. CERVICAL RIPENING AND IOL IN SPECIAL
CIRCUMSTANCES:
a) Previous C. S. :
· One or more previous C. S. are not a
contraindication to the induction of labor.
· Cervical ripening can be done in these situations
with PGE2 gel – either intravaginal or intracervical
· Misoprostol is an absolute contraindication
· Oxytocin can be safely used in low doses with
close monitoring of uterine contractions and FHR.
· It is preferable to have continuous electronic
fetal monitoring.

64. b) Twin pregnancy:
· PGE 2 gel can be safely used for cervical ripening
· ARM facilitates induction
· Oxytocin in low doses can be used
c) Premature rupture of membranes (PROM) :
· Use of PGE2 gel– 2 doses 6 hours apart is not associated with
higher incidence of infection
· Misoprostol can also be used in 25 mcg dose
· Oxytocin infusion should be closely monitored
· Beware of hyperstimulation

65. d) Intrauterine fetal demise (IUFD ) :
· Oxytocin is effective for IOL near term with a
favorable cervix.
· All prostaglandins can safely be used in
recommended dosages for cervical ripening remote
from term.

66. Induction of labor : Summary of evidence based ACOG
recommendations:
Recommendations based on good and consistent scientific evidence (
Level A)
 Prostaglandin E analogues are effective in promoting cervical
ripening and inducing labor
 Women in whom induction of labor is indicated may be
appropriately managed with either a low or high dose oxytocin regimen
 Fetal heart rate and uterine activity should be continuously
monitored from the time the PGE 2 vaginal insert is placed until at least
15 minutes after it is removed
 High dose PGE 2 vaginal suppositories may be used in the
management of intrauterine fetal demise in the second trimester of
pregnancy
 Although the optimal dose and timing interval of misoprostol is
unknown , lower doses ( 25 mcg every 3-6 hours) are effective for
cervical ripening and induction of labor


67. Recommendations based on evidence that may
be limited or inconsistent ( Level B):
 Misoprostol use in women with prior
cesarean birth should be avoided because of
the possibility of uterine rupture
 The use of higher doses of misoprostol (
50 mcg every 6 hours) to induce labor may be
appropriate in some situations , although there
are reports of increased risk of complications,
including uterine hyperstimulation.

68. Recommendations based onconsensus and expert
opinion ( Level C) :
 For women with third trimester intrauterine
fetal demises, intravaginal misoplrostol can be used to
induce labor.
 Fetal heart rate and uterine activity should be
continuously monitored from 30 minutes to 2 hours
after administration of PG E2 gel

69. Failure of Induction
It is defined when Cx failed to dilate up to 3-4 cm in 24 hrs of
induction.
What to do now ?
- Option to wait-- if No PROM and postponement is not
harmful for fetus as well as mother.
- Review the case and if there is urgency, Caesarean
delivery is performed.

70. What's new in monitoring of
labour ?
MONITORING UTERINE CONTRACTIONS :
Intra uterine pressures
FETAL MONITORING
Fetal pulse oximetry
Fetal electrocardiogram wave form analysis
Intermittent measurement of lactate by FBS
As an adjuvant to
EFM as it has high False positive rates