2. Induction Of Labour
Definition
Induction of labour after 28 wks of
gestation i.e. after period of viability but
before spontaneous onset of labour with aim
of vaginal delivery.
3. Induction Of Labour
The list of indication has lately been expanded to
cover a large number of maternal and fetal
conditions with the objective of reducing Maternal
Mortality & Morbidity ; as well as salvaging LIVE
babies .
The major risk is Iatrogenic Prematurity . The
Obstetrician is solely responsible for this and
hence it is mandatory to establish fetal lung
maturity (presence of surfactant factor) OR be
certain of fetal gestational age by serial
ultrasonography first / second / third trimester
, all inclusive .
4. Indications
1.POST DATED PREGNANCY
Beyond 40 wks of gestation, placental
insufficiency Chronic Fetal Hypoxia – Fetal Death.
Fetal asphyxia worsens with each week of
advancing
leading to a severely compromised fetus and
IUFD.
Reported fetal loss in Post dated pregnancy
0.7% at 37 weeks
5.8% at 43 weeks ( 8-fold increase).
5. Indications
1.POST DATED PREGNANCY (contd)
Timing of induction –controversial-- some prefer to wait
spontaneous onset of labor till 42 week, many others believe
there is no gain in waiting beyond 40 weeks.
CS rate rises sharply after 40 weeks.
Cost and stress of fetal monitoring while waiting for
spontaneous labor to start .
Need for emergency intervention --are the risks of wait &
watch policy.
Good success rate achieved with Induction with
Prostaglandins
at 40 weeks Prompts many Obstetrician to intervene if fetal
maturity is reached.
.
6. Indications
2. HYPERTENSIVE DISORDER
Hypertensive disorder of any origin can cause
placental insufficiency, IUGR fetal anoxia depending
upon severity and duration of hypertension.
Cerebra-vascular accidents ,eclampsia and abruptio
placenta can endanger maternal life.
Induction is planned at 37 weeks as fetal maturity is
gained.
But in state of worsening ---impending eclapmsia,
IUGR and placental abruption may require early
induction ---Corticoid therapy between 30-34 weeks
will reduce the risk of RDS in Newborn.
7. Indications
3.ECLAMPSIA
Once eclampsia supervenes , maternal and fetal
mortality rises.
Once the measures for controlling fits are done
and patient is stabilized, induction of labour /
Caesarean Delivery should be undertaken.
8. Indications
4.DIABETES
A sudden IUFD is not uncommon in last 6 weeks of
pregnancy complicated by long standing severe
Diabetes.
Monitoring Biophysical profile at twice week interval
and fetal lung maturity will determine the time and
method of termination of pregnancy.
Strict control of maternal blood sugar level, avoiding
maternal Ketoacidosis and fetal prematurity and
sudden IUFD must be the aim to be gained.
9. Indications
5.Rh INCOMPATIBILITY
A pregnancy complicated by Rh iso immunization
exposes the fetus to anaemia, jaundice and kernicterus
.
Amniocentasis, cordiocentasis and USG screening
done repeatedly can help to determine severity of fetal
affliction and time of induction.
Post maturity not allowed.
Pregnancy should be terminated as soon as lung
maturity is gained / fetal condition in utero is in state
of impending danger.
10. Indications.
6.ANTEPARTUM HEMORRHAGE
In placenta praevia nothing is gained by going
beyond 37 weeks as bleeding may start at any
moment .
Severe bleeding and concealed hemorrhage in
abruptio placenta need immediate termination of
pregnancy.
11. Indications.
7.INTRA UTERINE GROWTH
RETARDATION
IUGR due to any cause results in chronic fetal
asphyxia.
Further growth is impaired.
Fetus is worse off in utero than out side.
The optimal time for induction is determined by
bio physical profile.
12. Indications
8.PREVIOUS INTRA UTERINE FETAL
DEATH (IUFD)
It is desirable to terminate the pregnancy one week
before the time when IUFD occurred in last
confinement.
13. Indications
9.PREMATURE RUPTURE OF
MEMBRANES (PROM)
PROM leads to infection ,cord compression,
Oligohydramnios and fetal pneumonia.
If pregnancy is beyond 37 weeks and PROM has
lasted
more than 12 hrs without labour pains –Induction
of
labour is indicated.
14. Indications
10.DEAD FETUS(IUFD Present
Pregnancy).
To avoid infection and DIC , Pregnancy with
dead fetus should be terminated by medical
induction as early as possible .
DIC earliest documented after 5 days
15. Indications
.
11.MALFORMED FETUS.
Gross malformation of fetus incompatible
with life
necessitates termination.
The routine practice of USG in mid trimester
eliminates the delayed detection of gross fetal
malformation in late pregnancy .
16. Indications
12.UNSTABLE LIE
Stabilizing induction is sometime recommended in a
multipara. Stabilizing induction may effect vaginal
delivery and avoid a caesarean section.
17. Indications
13.SOCIAL INDUCTION
• Also known as elective induction for convenience of
family and obstetrician must be discouraged
.Induction by any method is not 100% successful.
• Failed induction may necessitate unneccessary
LSCS.
19. Indications For Caesarean Section
Medical /Surgical induction is contraindicated, but
early termination of pregnancy is must to save guard
the life of mother and fetus.
When CS is selected on obstetrical grounds such as
Contracted Pelvis , Abnormal Fetal Presentation /
Position , Previous scar of CS
, Hysterotomy, Myomectomy etc.
20. Pre-induction Evaluation
1.Indication-One must be certain that induction of
labour is warranted in a particular woman. The
balance between Risks and advantages of induction
and continuation of pregnancy must go in favor of
induction.
2.Time of induction– Iatrogenic prematurity
should be avoided. In maternal indications fetal
maturity is less important e.g. Status eclampticus.If
premature induction is planned , Corticosteroid
therapy will reduce the risk of Fetal RDS / Hyaline
Membrane Disease.
21. Pre-Induction Evaluation
3.Bishop Score
Score O 1 2 3
Cervical
Dilatation <1cm 1-2cm 2-3cm >4cm
Effacement 0-30% 40-50% 60-80% >80%
Cervical length >2cm 2-1 cm 1-0.5 cm <0.5 cm
Consistency Firm Medium Soft --
Station -3 -2 -1 , 0 +1,+2
>3 cm >2cm < 2 cm 1+,2 + cm
above above I.S. above I .S. below I.S.
Ischial
spine
Cervical Mid Anterior
Position Position
Posterior
22. Pre-induction Evaluation
4.Pelvic Assessment
Pelvic assessment should be done to confirm
whether vaginal delivery is possible or not.
The success of induction depends on parity of
woman, gestational age, Bishop Score. Bishop score
of >9 is very favorable and nearly 100% success in
induction is expected. 6-9 Bishop Score--70-80%
success , Bishop Score<6 is associated with > 20%
failure rates.
23. Methods of Induction of Labour
1.Mechanical Laminaria Tent
Nipple Stimulation
Sweeping membranes
Extra Amniotic insertion
catheter/balloon
2.Surgical ARM
3.Medical Prostaglandin
(Cerviprime/Dinoprostone) Relaxin
gel, Prostaglandin Tablets (Primiprost)
, Misoprostol Tablets , Oxytocin, Mifepristone
, Oestrogen pessary .
4.Combined Surgical and Medical
24. 1. Mechanical Methods
Laminoria tent--A stem of sea weed imbibes water and
swells up ,slowly dilates Cx.Local prostagandins are also
released. Lamicel,Isogel tent are also used.
Disadvantages---Slow dilataion,infection,accidental
ARM,not recomonded in IUFD cases.
Nipple Stimulation--It releases pitocin from Posterior
pituitary and initiate uterine action Failure rate is very
high
Sweeping of membranes--PG released .Cervical
stretching --Ferguson reflex.
Extra Amniotic insertion of catheter/balloon--Mechanical
stretching of Cx and separation of membranes release
PG. catheter is removed after12 hrs and Syntocinon drip
is started.
Displacement of presenting part , ARM Infection may
25. 2.Surgical methods
ARM--to be done in morning hrs when pt is empty
stomach--risk of cord prolapse--immediate LSCS may be
undertaken.
Precautions--
Timing-- when Cx is dilated >3cm.
Visualise colour of amiotic fluid for meconium staining.
Application of scalp electrodes for fetal heart
monitoring.
Syntocinon drip started after 12 hrs/earlier .
Watch for any bleeding in cases of APH , bleeding
increases or
decreases.
26. 2.Surgical methods
ARM
Risks of ARM
1.Cord prolapse when presenting part is not engaged.
2.Sepsis if time interval is prolonged / multiple PV
examinations are
done.
3.Failure of induction , when Bishops Score is < 6.
Contraindications of ARM
Abnormal Fetal Presentation : Transverse Lie , Breech
, Brow , ROP , Face , Multiple pregnancy .
Unengaged head
Dead Fetus--Sepsis.
27. 3.Medical Methods
Locally acting-
1. Oestradiol 150mg Vaginal pessary OD/BD –PV
insertion help in ripening the cervix in 90% cases.It
releases PG and proteolysis leukocyte Induce
ripening.Collegen content is reduced & Cx Is softened.
2. Relaxin 2mg gel exerts similar action.
3. Anti Progesteron (RU 486)- Mefepristone---enhances
PG action.200 mg daily for2days prior to formal
induction is effective in softening and effacement of Cx.
4.PGE2 & PGF2 a -----PGE2 acts mainly on Cx and
cause cervical ripening. PGF2a Initiates uterine
contractions Not recommended.
28. 3.Medical Methods
PGE2 - 500ug viscous gel or 50ug in 0.5ml injection repeated
every ½ hrly (Maximum 3 ml ) through extra amniotic
transcervical foley’ catheter. It starts cervical softening and
uterine action.PGE2 is 5-10 times more potent. This method
bears disadvantages of mechanical methods and fetal distress.
PGE2 gel ½ ml (0.5) ml
(cerviprime/dinoprost) is instilled in cervical canal.
Cervical ripening occurs in 40% cases with in 4-6
hrs.15% may not have any response.
PGE2 tabs-3mg and 1mg- gel available . PV gel is
rapidly absorbed and more effective than tabs. Dose
may be repeated 3hrly according to status of FHS and
uterine action.
Hypertonicity is reported 7.3% and 0.5% with tablets
and gel respectively.
29. 3.Medical Methods
Misoprostol(PGE1) -- It is stable at room
temperature. Its half life is 3 yrs ,GI disturbances
and fever are its disadvantages. Misoprostol 25ug 3
doses at 3hr interval is effective . Higher dose
100ug 4hrly orally /400ug 3hrly given sublingually
but GI symptoms are sometime troublesome.
Monitoring for fetal distress ,hyper tonicity is
must.
Glycerol trinitrate induces painless induction.
Nitric oxide skin patch (50mg) with a surface area of
20 cm acts fast in 24 hrs.
30. 3.Medical Methods
Systemic drugs 1.Oral Prostaglandin
2.Syntocinon Drip
1. Oral Prostaglandin - A 0.5 mg tablet of primiprost/Prostin
is taken as 1st dose . Dose is increased as ½ tablet every hrly until
3 contractions are there in each 10 minutes /maximum 3 tablets
are administered.
Contraindications for PGS -- Bronchial Asthma , Cardiac
disease PGE2 causes hypotension , PGF2a causes hypertension &
tachycardia , Glaucoma , Epilepsy , Renal disorders , Fetal
distress , Previous LSCS/SCAR.
Side Effects--
Nausea, vomitting, diarrhoea, Burning in vagina, Cervical
tear, Uterine Rupture in1% cases mostly multiparas . Fetal
distress , Hyperstimulation Syndrome , Amniotic Fluid Embolism
, Failure 10-20 % require LSCS.
31. 3.Medical methods
2. Syntocinon Drip Synthetic version of
Oxytocin a hormone secreted by posterior pituitary
gland. It is a Neuropeptide synthetized in
supraoptic and paraventricular nucleus of the
Hypothalamus and released into post pituitary
veinous plexus. Its ½ life is 3-4 minutes and effect
lasts
for 15-20 minutes.
Syntocinon –orally-desrtoyed in stomach,
irregular and slow absorption when given
buccal/sublingual route . If given IM rapidly
destroyed by Oxytocinase enzyme.
32. 3.Medical methods
2. Syntocinon Drip
Syntocinon -- How to start? By titration method -
one unit in 500ml 5% GDW/saline10-15 drops/minute
drip started. Uterine action and FHS monitored ,dose
is Increased gradually as per uterine action & FH rate,
till 3 contractions in 10 minutes start . Syntocinon drip
is stopped if there are signs of fetal distress. It is
necessary to maintain the drip after delivery for at least
2-3 hrs to avoid delayed PPH.
Oxytocin infusion pump--Can regulate the dose of drug
and control the uterine action effectively as well as
limit I V Fluids.
33. 3.Medical methods
2.Syntocinon
Indications
1. Induction, Augmentation, acceleration of labur.
2. Control of atomic PPH in higher dose (20-40units in
running drip).
3.In abortion , MTP, Vesicular Mole - evacuation.
4. Prophylactic use in 3rd stage of labour.
5.Letting down reflex for milk secretion, breast
engorgement.
6.Secondary uterine inertia in prolong labour case if
there is no fetal distress/ inco-ordinated uterine
action .
35. 3.Medical methods
Syntocinon Complications
1. Hypertonic uetrine action---rupture uterus.
2.Fetal distress and fetal death.
3.Delyed PPH if drip is withdrawn soon after delivery.
4.Maternal Hypotension if given in volous form.
. Waterintoxication,hypernatraemia.,convulsiovn and
coma.
6.Amniotic fluid embolism.
7.Hyperbilrubinaemia in newborn.
.
36. 4.Combined Methods
Combined method ( medical & surgical) is often
required in induction of labour , it yields 80% of
success rate .
37. Special Conditions
1.Dead fetal--Cervical ripening by PGs, augmentation by syntocinon
and ARM Under antibiotic .Extra amniotic instilation of
emicradil100-200ml.
2.Previous Caesarean Section--The choice depends upon Bishops
score , integrity of scar.
3.Twin Pregnancy--only indicated when1st fetus is LOA.
4.Breech Presentation--No ARM. Cervical ripening needs careful
monitoring. LSCS is considered safer than induction.
5.PROM--Longer the interval between PROM and delivery, greater
is risk of infection and fetal distress.PGE2 vaginal Tablet or
syntocinon drip is indicated if uterine contraction do not start
within 12hrs of PROM.
38. Choice of Method
It depends upon parity,station of presentng
part,State of membranes , Bishop’s score, Period of
gestation.
Low parity , low Bishops score predisposes to
prolonged labour and poor neonatal outcome --
higher incidence of LSCS.
PGS have improved the success rate, hence used
more to ripen Cx improve Bishops score and initiate
uterine action.
Syntocinon drip is used when PGS fail or added to
augment.
39. 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.
Notas do Editor
When Bishop Score is 0-3 caeaerian section-------45% in primipara and 7.7% in multiparas When it is 4-6----c.s. rate is 10.3%and 3% respectively. Higher score <7C.S. rate is 1.6%and 0.9% respectively.