Induction of labour is defined as the elective process of artificially initiating and maintaining uterine contractions with cervical effacement and dilatation resulting in the delivery of the baby.This is a therapeutic option when the benefits of expeditious delivery outweigh the potential maternal and foetal risks of continuing pregnancy

Induction

it implies stimulation of contractions before the spontaneous onset of labor, with or without ruptured membranes.

Augmentation

It refers to - intervention to correct slow progress in labor.

Correction of ineffective uterine contraction includes Amniotomy and/or Oxytocin infusion

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MATERNAL

Preeclampsia,eclampsia PROM Postterm pregnancy Abruptio placenta Chorioamnionitis Medical conditions-

DM,Heart ds, Renal ds,Chr. HT etc

Prolonged pregnancy

FETAL

IUD Fetal anomaly

incompatible with life Severe IUGR Rh isoimmunisation Macrosomia Oligohyrdamnios

Contraindications to induction of labour centre primarily on the risks of uterine hyperstimulation vis a vis uterine integrity.

Classical caesarean section Inverted T J incision Unknown Uterine Surgery Hysterotomy Myomectomy with entry into uterine

cavity/extensive dissection Previous uterine rupture

More than one previous ceasarean section HIV positive mothers Suspected cephalo pelvic disproportion Cord presentation Severly compromised foetus Multiple pregnancy(triplets and above) Active herpes genitalis Foetal malpresentation

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Establish indication clearlyInformed consentConformation of gestational ageAssessment of fetal size & presentationPelvic assessmentCervical assessment (BISHOPs score)Availability of trained personnel

Cervix favourability

- The most important determinant of successful induction of labour is the favourability of the uterine cervix.Cervical assesment is made utilising the Modified Bishop’s Score.If the score indicates that the cervix is not favourable,cervical ripening is required

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Characteristics012

1.PositionPosteriorAxialAnterior

2.Length2cm1cm0cm

3.Dilatation<1 cm1cm 2cm

4.ConsistencyFirmSoftStretchable

5.Station-2-10

A favourable cervix is defined as one with a modified Bishop Score of > 6

Until recently, the most common practice has been to induce labor by the end of the 42nd week of gestation. This practice is still very common.

Recent studies have shown an increasing risk of infant mortality for births in 41st and particularly 42nd week of gestation, as well as a higher risk of injury to the mother and child .

The recomended date for induction of labor has therefore been moved to the end of the 41 week of gestation in many countries

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Method of induction

Most methods of inducing labour before the last half century involved mechanical manipulations, including,

Galvinism, repeated pressurised douches, extra-amniotic aqua picea, tents, bougies and catheters.

Among the more common approaches are frequent walking, vaginal intercourse, participating in heavy exercise, consumption of laxatives, spicy foods or herbal tea, nipple stimulation and administration of an

enema

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NATURALBreast/nipple stimulationSexual intercourseMembrane strippingAcupuncture/acupressure

MECHANICALBalloon cathetersLamineria tentsSynthetic osmotic dilators

CHEMICAL

NONHORMONAL Herbs,evening primrose oil Homeopathic prep Enemas Castor oil

HORMONAL

Oxytocin

Prostaglandins –PGE2

Relaxin

Nitric oxide donors

mifepristone

Several effective methods of cervical ripening and induction of labour are used for initiating labour at or around term. Currently, medical expert consensus recommends the following:

◦ Sweeping the membranes

◦ Artificial rupture of membranes (ARM)

◦ Prostaglandin E2 (PGE2)

◦ Intravenous oxytocin (Pitocin)

◦ Foley’s catheter

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Use of the Foley catheter technique alone, in which catheters are passed through an undilated cervix before inflation, was shown to be as effective as use of PGE2 gel.

The successful use of extra-amniotic saline infusion with a balloon catheter has also been reported

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. The balloon portion of the Foley, used to keep the bladder empty, is inserted into the uterus feeling that the balloon is between the amniotic sac and the lower uterine segment (bottom of the uterus).

The balloon is then inflated with saline solution and left in place

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The goal of this induction is to cause the cervix to mechanically open. Sometimes this will start labor spontaneously and sometimes it will simply make the cervix more favorable for a Pitocin, other drug induction or amniotomy

You may have to have baby's heart rate monitored before, during and just after the procedure to see if the baby tolerated this process, but this is very unlikely to cause fetal distress because it does not use drugs.

To review after 24hours or when ballon falls or when patient has contraction 3:10 moderate 18

Stripping of the membranes causes an increase in the activity of phospholipase and prostaglandin as well as causing mechanical dilation of the cervix, which releases prostaglandins.

performed by inserting the index finger as far through the internal os as possible and rotating twice through 360 degrees to separate themembranes from the lower segment

Risks of this technique include infection, bleeding, accidental rupture of the membranes, and patient discomfort.

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The reviewers concluded that stripping of the membranes alone does not seem to produce clinically important benefits,but when used as an adjunct does seem to be associated with a lower mean dose of oxytocin needed and an increased rate of normal vaginal deliveries.

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Cervical dilator is a HYDROPHILIC polymer rod used for dilation and ripening of the cervix. When inserted into the cervical canal, these sterile

rods act in two ways

-Draws fluid from the cervical tissue into the rod causingexpansion of the rod which produces an outward radial force

-Initiates endogenous prostaglandin release causing collagen degradation which softens the cervix

-Made from a synthetic polymer so there is no drug side effects extremely resistant to breakage - elastic characteristic allow for safe removal even when entrapped.

-Use of hygroscopic dilators are reported to be associated with

increased peripartum infections

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M/A :Act on the cervix to enable ripening by a number of different mechanisms.

They alter the extracellular ground substance of the cervix, and PG increases the activity of collagenase in the cervix.

They cause an increase in elastase, glycosaminoglycan, dermatan sulfate, and hyaluronic acid levels in the cervix. A relaxation of cervical smooth muscle facilitates dilation.

prostaglandins allow for an increase in intracellular calcium levels, causing contraction of myometrial muscle..

Contraindications

Known hypersensitivity to dinoprostone gel, Prostin E2 vaginal tablets or its constituents (triacetin, colloidal silica or urethane)

History of previous uterine surgery including caesarean section

Ruptured membranes

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Intravaginal mode of administration

Dinoprostone gel dosage

The initial dose for dinoprostone (PGE2) gel is 2 mg per vaginam (PV) in nulliparous women with an unfavourable cervix , 1 mg PV for multiparous women and 1 mg PV in cases of suspected fetal compromise (intra uterine growth restriction)

A second dose of 1-2 mg of dinoprostone (PGE2) gel may be administered 6 hours later

The maximum dose in a 12 hour period is 4 mg PGE2 for nulliparous women with an unfavourable cervix and 3 mg for all other women

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Patient selection: Patient is afebrile.

No active vaginal bleeding is present.

Fetal heart rate tracing is reassuring.

Patient gives informed consent.

Bishop score is < 4.

Complete 20 minutes CTG tracing that fulfils the hospital’s accepted criteria

Ensure the woman has emptied her bladder

Confirm maternal pulse, blood pressure, respiration rate and uterine activity meet accepted criteria

Abdominal palpation to confirm cephalic presentation

Vaginal examination to obtain a modified Bishop score

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Insert dinoprostone (PGE2) gel into the posterior fornix of vagina .

Advise the woman to remain recumbent in 30˚ left lateral tilt for at least thirty minutes (allows prostaglandin absorption) before sitting up or walking around

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Dosage and procedure:

CTG -before induction,1 hour after induction

Fetal heart monitoring – ¼ hourly, ½ hourly for 2hours, and hourly for 4hours

Contraction monitoring Review vaginal examination by MO in

6hrs

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One tablet (3 mg) to be inserted high into the posteriorfornix. A second tablet may be inserted after six to eight hours if labour is not established. Maximum dose 6 mg/24hrs

Not more than 2 prostin per day unless decided by specialist

If patient failed to progress after 3rd prostin,specialist to make further decision

Usually patient is allowed a day rest before 4th prostin

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After the maximum dose has been administered, if the cervix is favourable, induction can be undertaken immediately with amniotomy

 Pitocin augmentation may be commenced 6 hours after the last dose of PGE2 gels has elapsed to avoid uterine hyperstimulation

Admission to the labour / delivery suite should occur before amniotomy or Pitocin augmentation is commenced

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Inform the woman to notify the midwife should uterine contractions become regular and / or painful, or if the woman has any vaginal loss

Ensure there is a documented plan for ongoing management in the woman’s case notes

If not in labour within 12 hours of the first dose of dinoprostone (PGE2) gel or Prostaglandin E2 vaginal tablet, review IOL management

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The risk of hyperstimulation was reduced when compared with prostaglandins (intracervical, intravaginal ). Compared to oxytocin in women with unfavourable cervix, mechanical methods reduce the risk of caesarean section

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ARM is a surgical procedure to induce or augment labour

Amniotomy for induction :used to induce labor but, it implies a

firm commitment to delivery :disadvantage -the unpredictable and occasionally

long interval to delivery

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Cord prolapseTo reduce the likelihood of cord prolapse, which may occur at the time of amniotomy, the following precautions should be taken:

• Before induction, engagement of the presenting part should be assessed.

• We should palpate for umbilical cord presentation during the preliminary vaginal examination and avoid dislodging the baby’s head.

• Amniotomy should be avoided if the baby’s head is high.We should always check that there are no signs of a low-lying placental site before membrane sweeping and before induction of labour.

Indications Pitocin is a synthetic oxytocin and the most common

induction agent in use It may be used:

◦ Alone ◦ In combination with amniotomy ◦ After cervical ripening with other pharmacological or

non pharmacological methods Induction of labour using a combination of amniotomy

and intravenous Pitocin is the preferred method of induction for women who have a favourable cervix

When compared to dinoprostone (PGE2) gel, induction with Pitocin® results in a lower rate of some infective sequelae e.g. chorioamnionitis in women who have ruptured membranes 

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Primigravida

-2 unit of pitocin in 500mls Dextrose saline and start at 15dpm,increase every 30,45 and 60dpm.

-May increase to 4unit and 8unit if good contraction failed to achieve.

-Good contraction is 4-5 contraction in 10minutes lasting 45 seconds

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Para 2-4

1,2,4 units of Pitocin in 100mls normal saline

Start at 9mls/H then increase to 18mls/H, 27mls/H to maximum of 36mls/H

Para 5 & above

, ½1 ,2 units in 100mls Normal saline

Start at 9mls/H then increase to 18mls/H, 27mls/H to maximum of 36mls/H

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InterventionsRational

1-Explain procedure.1-to reduce anxiety

2-Apply fetal monitor and monitor FHR.

2-To establish baseline and ensure fetal activity.

3-Start an

electrolytes

solution I.V infusion (primary line)

3-To minimizes the risk of water intoxication.

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InterventionsRational

4.Add the prescribed amount of oxytocin

4-Oxytocin must be administered with an infusion pump to ensure accurate dose administration.

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InterventionsRational

5-Monitor FHR, uterine contraction (frequency, duration, and intensity), BP,and Pulse and record at intervals comparable to the dosage regimen. All observation and increases or decreases in oxytocin are documented on the fetal heart tracing and mother chart.

6-If uterus become hyperstimulated, blood flow to uteroplacental site will be decreased and fetus will suffer from hypoxia.

6 -Once the desired frequency of contractions has been reached (every 2 to 3 minutes and 45 to 60 second's duration. oxytocin may be stop or reduced the increases of the rate.

7-Sensitivity to oxytocin increases as labor progresses.

These results indicate that the pattern of normal labor has been established.

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Contraction occur more frequently than every 2 minutes.

Duration of contraction is longer than 90 seconds.

Elevation of resting tone of uterus is greater than 15 to 20 mmHg over her baseline of intrauterine pressure.

Blood pressure increases when contractions increase in frequency, duration, and intensity because of decrease in uteroplacental circulation.

Client experience increasing pain because of increased frequency, duration, and intensity of contractions.

Sustained tetanic contractions occur.

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Tachycardia or bradycardia. Late decelerations, variable

decelerations, or prolonged deceleration.

Loss of variability. Increased fetal activity. Excessive molding or caput-

succedaneum formation. Meconium stained amniotic fluid in

cephalic presentation.

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InterventionsRational

1-Turn off immediately oxytocin infusion

1-To prevent fetal anoxia and uterine rupture.

2-Turn woman on her left side.

2-To improve fetal-placental blood flow.

3-Increase primary I.V rate up to 200 ml/hr unless contraindicated.

3-To provide adequate intravascular volume, support maternal BP, and I.V route for emergency medications.

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InterventionsRational

4-Give oxygen 6 to 10 l/min ( per protocol) by face mask.

4-To saturate the blood with oxygen as much as possible to prevent fetal anoxia.

5-Notify experience doctor5-This indicate induction failed. If membrane intact discontinue induction and try again later. If membrane ruptured cesarean birth may be necessary.

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In addition to hyper-stimulation of uterus and fetal distress those complications may occur:

Ruptured uterus as a result of over-stimulation if any cephalopelvic disproportion present.

Amniotic fluid embolism is rare which may caused by strong, tumultuous contractions. (usually occur in 3rd stage after placenta separation and with tetanic condition of uterus)

Antiprogestins

Epostane, the 3ß-hydroxy dehydrogenase inhibitor, and subsequently mifepristone, the progesterone receptor blocker, were shown to have a dramatic effect upon reducing induction to abortion intervals during second trimester therapeutic abortion.A more recent large study involving mifepristone 200 mg produced very similar conclusions but unfortunately women of mixed parity were studied and conclusions must be guarded

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Dehydroepiandrosterone sulphate

Intravenous dehydroepiandrosterone sulphate (DHEAS), which is transformed into oestrogens in the fetoplacental unit, has been explored as a possible cervical ripening agent, achieving effacement without inducing uterine contractions.

Relaxin

This polypeptide has been studied in humans, using purified porcine relaxin 1–4 mg in viscous gel vaginally or endocervically. It was hoped that it would have the same properties as exhibited in certain animal species. To date, there have been no well-conducted trials to determine its value for ripening the unfavourable cervix

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Nitric oxideThere have been a number of studies suggesting that nitric oxide is involved in the process of cervical ripening during the latter stages of pregnancy

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Breast stimulation It has been suggested as an effective inexpensive non-

medical means of inducing labour. A Cochrane Database review of six randomised controlled trials involving 719 women reported a significant reduction in the number of women with a favourable cervix not in labour 72 h following the start of nipple stimulation compared with no intervention. There was, however, no reduction in the need for delivery by caesarean section

Sexual intercourse during the latter weeks of pregnancy has been

suggested as a logical strategy to encourage labour since semen is presumed to contain the highest prostaglandin concentration of any body fluid.

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Failure leading to CS

Uterine hyperstimulation

Fetal distress,death

Rupture uterus

Intrauterine infection,sepsis

Iatrogenic delivery of preterm infant

Precipitate/dysfunctional labour

Inc. risk of operative vaginal delivery

Inc. risk of birth trauma

Inc. risk of PPH

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Failed induction

Failed induction is defined as labour not starting after one cycle of treatment

If induction fails, healthcare professionals should discuss this with the woman and provide support.

The woman’s condition and the pregnancy in general should be fully reassessed, and fetalwellbeing should be assessed using electronic fetal monitoring.

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If induction fails,the subsequent management options include:

•a further attempt to induce labour (the timing should depend on the clinical situation and the woman’s wishes)

•caesarean section

Induced labour tends to be more intense and painful for the woman, often leading to the increased use of analgesics and other pain-relieving pharmaceuticals (Vernon, 2005).

This cascade of intervention has been said to lead to an increased likelihood of caesarean section delivery for the baby. (Roberts 2000).

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Guidelines on management of induction of labour-Kementerian Kesihatan Malaysia

Obst & Gynecology Guidelines and protocols-HOS SHAS

Obst by Ten Teachers- Philip N Baker Mayo clinic ref. Various internet web sites

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