INDUCTION OF LABOUR

Prof. M.C.BansalMBBS,MS,MICOG,FICOG

Professor OBGYEx-Principal & Controller

Jhalawar Medical College & HospitalMahatma Gandhi Medical College, Jaipur.

INDUCTION OF LABOUR

Definition Induction of labour after 28 wks of

gestation but before spontaneous onset of labour with aim of vaginal delivery.

INDICATIONS

The list of indication has lately been expanded to cover a large number of maternal and fetal conditions with the objective of reducing MMR &morbidity as well as salvaging the babies ----

1.Post date pregnancy Beyond 40 wks of gestation ,placental insufficiency Ch. Fetal asphyxia –fetal death.

Fetal asphyxia worsens with each weak of advancing leading to a severely compromised fetus and IUFD.

POST DATED PREGNANCY----- Reported feta loss --- 0.7% at 37 weeks 5.8% at 43 weeks ( 8-fold increase).Timing of induction ---controversial---. some prefer to wait

spontaneous onset of labor till week, many other 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 at40 weeks Prompts many Obstetrician to intervene if fetal maturity is reached.

.

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.

3.ECLAMPSIA

Once eclampsia supervenes , maternal and fetal mortality rises.

Once the measures for controlling fits are done and pt is stabilized induction of labour / CS should be undertaken.

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.

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.

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.

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.

8.PREVIOUS INTRA UTERINE DEATH (IUFD)

It is desirable to terminate the pregnancy one week before the time when IUFD occurred in last confinement.

9.Premature rupture of membranes(PROM)—

PROMS 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.

10.DEAD FETUS.

To avoid infection and DIC Pregnancy wt dead fetus should be terminated by medical induction.

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 .

12.UNSTABLE LIE

Stabilizing induction is sometime recommended in a multipara. Stabilizing induction may effect vaginal delivery and avoid a caesarean section.

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.

CONTRAINDICATIONS TO INDUCTION OF LABOUR Prematurity Previous Caesarean scar Myomectomy Scar Hysterotomy Scar Contracted Pelvis Uncorrectable Transverse Lie Brow Presentation

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.

PRE-INDUCTION EVALUATION

1.Indcation-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 indication is planned ,Corticosteroid therapy will reduce the risk of fetal RDS.

3.BISHOP SCORE

Score O 1 2 3

Cervical Dilatation

Effacement

Cervical length

Consistency

Station

Cervical Position

0-<1cm

0—30%

>2cm

Firm

More than3 cm above Ischial spine

Posterior

1-2cm

40-50%

2-1 cm

Medium

>2cm above I.S.

Mid POsition

2-3cm

60-80%

1-0.5 cm Soft

-1. o<2 cm above I .S.

Anterior

>4cm

>80%

<0.5 cm

--

1+,2 + Below I.S.

--

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. 6-9Score----70-80% success ,Score<6 is associated with > 20% failure rates.

METHODS OF INDUCTION OF LABOUR

1.Mchanical Laminaria Tent Nipple Stimulation Sweeping membranes Extra Amniotic insertion of

catheter/balloon2.Surgical ARM

3.medical Oestrogen pessary, Prostglandin Relaxin gel, Oxytocin, Mifepristone

4.Combined Surgical and Medical

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 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 occur Mechanical methods are not useful in cases of PROM and IUFD .

3.MEDICAL METHODS Locally acting- 1. Oestradiol 150mg Vaginal pessary OD/BD –PV insertion help in

ripening the cervixin90% 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. PGE2----500ug viscous gel or 50ug in 0.5ml injection repeated every ½ hrly

(Maximum 3 ml ) through extra amniotic trans cervical folley’ 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 (cerviprim/cerviprost)is instilled in cervical canal. Cervical ripening occurs in40% cases with in 4-6 hrs.15% may not have any response.

PGE2 tabs---3mg and 1mg gel /pv gel is rapidly absorbed and more effective than tabs. Dose may be repeated 3hrlyaccording to status of FHS and uterine action.

Hypertonicity is reported 7.3% and 0.5% with tablets and gel repictvely.

MEDICAL METHODS Mesoprostol(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.

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 conractions are there in each 10 minutes /maximum 3 tablets are administered.

Contraindications for PGS --Bronchial Asthma, Cardiac diseasePGE2 caseshypotension,PGF2a –hypertension and tachycardia .Glauma,Epilepsy,Renal disorders,fetal distress,previous LSCS/SCAR. sideeffects- --Nausea, vomittings, diarrhoea., Burning in vagina, Cervical tear, uterine rupturein1% cases mostly multiparas. Fetal distress,hyperstimulation syndrom,amniotic fluid embolism, Failure----10-20 % require LSCS.

MEDICAL METHODS ------ Syntocinon Synthetic version of Oxitocin a

hormone secreted by posterior pituitary gland. It is a Neuropeptide synthetized in supraoptic and paraventricular nucleus of the Hypothalamus and released in to post pituitary gland. 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—neutralized by Oxytocinase enzyme.

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 uterne action effectively.

SYNTOCINON------ Indication1. Induction, Augmentation,

acceleration of labur.2. Control of atomic PPH in higher dose (20-40units in running drip).

3 .In abortion ,MTP, Vasicuarmole---evacuation. 4. Prophylactic use in 3rd stage of labour. 5.Letting down reflex for milk secretion, breast

engorgement. 6.Secodary uterine inertia in prolong labour case

if there is no fetal distress/ inco-ordinated uterine action .

SYNTOCINON------

Contraindication 1. Grandmultiparas—risk of rupture of uterus. 2.Contracted Pelvis, Pelvic tumour,

stenosed/scarred/cervical dystosia. 3.Malpresntations---persistent ROP, Tr. Lie.,

Brow ,posterior Mantum, multiple pregnancy. 4.previous hystertomy, myomectomy, LSCS scar. 5. obstructed labour.

SYNTOCINON------ Complications 1. Hypertonic uetrine action---rupture uterus. 2.Fetal distress ad 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.

.

SURGICAL METHODS----- ARM---to be done n morning hrs when pt is empty

stomach---risk of cord prolapse---immediate LSCS may be taken.

Precausions------- Timing---- when Cx is dilated >3cm. 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.

ARM------ Risks of ARM---- 1.Cord prolapse when presenting part is not

engaged, Sepsis if time interval is prolonged/ multiple PV examinations are done. Failure of induction. when Bishops Score is <6-7.

Contraindications of ARM---- -Abnormal fetal presentation—Tr. Lie. Breech,

Brow,ROP,Face,multiple prehnancy. -Unengaged head -Dead fetus---- sepsis.

COMBINED METHODS-

Combined method ( medical & surgical) is often required in induction of labour ., it yields 80% of success rate ,

SPECIAL0NDITIONS------1.Dead fetal---Cervical ripening by PGs, augmentation by syntocinon

and ARM Under antibiotics.

2.Previous Caesarian Section---The choice depends upon Bishops score ,integrity of scar.

3.Twin Pregnancy—only indicated when1st fetus is LOP.

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.

CHOICE OF METHOD-----

It depends upon parity,station of presentng part,State of membranes,Bishpos score,Period of gestation.

Low parity ,low Bishops score predisposes prolong 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 uerine action.

Syntocinon drip is used when PGS fail or added to augment.

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 urgency, Caesarean delivery is performed.