INDUCTION OF LABOUR

Induction of labour is defined as the process of artificially stimulating the uterus to start labour

General principles for induction of labour (WHO 2011)

1. Induction of labor should be performed only when there is a clear medical indication for it and the
expected benefits outweigh its potential harms.
2. When inducing labor, consideration must be given to the actual condition, wishes and preferences of
each woman, with emphasis being placed on cervical status, the specific method of induction of labor
and associated conditions such as parity and rupture of membranes.
3. Induction of labor should be performed with caution since the procedure carries the risk of uterine hyper
stimulation and rupture and fetal distress.
4. Wherever induction of labor is carried out, facilities should be available for assessing maternal and fetal
well-being.
5. Women receiving oxytocin, misoprostol or other prostaglandins should never be left unattended.
6. Failed induction of labor does not necessarily indicate caesarean section.
7. Wherever possible, induction of labor should be carried out in facilities where caesarean section can be
performed.
Indications
 When the health or well being of the mother or the foetus would be endangered if the pregnancy
continues
 Prolonged pregnancy because after 42 weeks there is danger of placental insufficiency
 Preeclampsia, where both mother and baby are in danger, with the mother in danger of eclampsia and
the baby in danger of placental insufficiency
 Signs of intrauterine growth, retardation, which can be detected by abdominal examination or serial
ultrasound scan
 Placental insufficiency more common in primigravida aged over 35 years
 Poor obstetric history, for example, history of stillbirth or intra uterine growth retardation in previous
pregnancies
 Polyhydramnious, foetal abnormalities
 Spontaneous rupture of membranes. If membranes rupture spontaneously after 36 weeks gestation and
labour does not commence within 12 hours, danger of intra uterine infection is very high
 Previous large baby, where weight was over 4kg. Induction is indicated between 38 - 40 weeks. Foetal
size tends to increase with successive pregnancies
 Diabetes mellitus, noting that intrauterine death tends to occur near term so induction is indicated
between 36 - 38 weeks
 Rhesus iso-immunisation, where rhesus antibodies are present in the maternal serum and the titre is
high, labour should be induced to save the life of the baby
  Unstable lie when placenta praevia and pelvic abnormalities have been excluded
 Previous precipitate labour which tends to recur so induction is indicated at 38 weeks
 Social reasons, which is not common in our community but occurs sometimes
 Intrauterine fetal death
Contraindications for the Induction of Labour
Absolute contraindications to induction of labour include:
 Cephalopelvic disproportion
 Oblique or transverse lie
 umbilical cord prolapse,
 active genital herpes infection,
 placenta previa,
 vasa praevia,
 Foetal compromise, that is, if the foetus could not stand the uterine contractions due to prematurity or
placenta insufficiency. In such cases caesarean section is preferred
 pelvic structural abnormality,
 Unreliable estimated date of delivery. Confirm estimated date of delivery and maturity by ultrasound
 Psychological factors, for example, if the mother is against induction, her decision should be
respected
 invasive cervical cancer and
 women who have had a previous myomectomy or more than 2 previous C/sections.
Relative contraindications to induction of labour: Abnormal foetal heart patterns, breech presentation,
maternal heart disease, polyhydramnios, and severe maternal hypertension

Favourable factors for induction include:

 38 or more weeks of gestation
 Bishop's score of six or more
 Where 3/5ths of the head or less is palpable above the pelvic brim

There are different methods of induction, which are:

 Medical, where drugs alone are used and the amniotic sac remains intact
 Surgical, where the membranes are artificially ruptured
 A combination of medical and surgical intervention

Medical induction
Prior to inducing labour, it is important to perform bishops scoring of the cervix. This will help to determine
the method of induction, whether cervical ripening is needed, as well as projecting the success of the
induction. The table for Bishops scoring is outlined below:
Bishop System of Cervical Scoring
Assessment Dilation (cm) Length of Foetal station* Consistency Position
score cervix (cm) or
Effacement (%)
0 0 >2cm -3 Firm Posterior
0 to 30
1 1 to 2 2cm -2 Medium Mid
40 to 50
2 3 to 4 1cm -1, 0 Soft Anterior
60 to 80
3 5 to 6 <0.5cm +1, +2, +3 -- --
90 to 100

*-3 = engaged; +3 = on the perineum.

Each score is awarded 0 - 3 and the range of scores is 0 - 13. A total score of six or over is favourable.
However a score of nine or more will have a safe, successful induction with an estimated length of labour of
less than four hours.

Low doses of vaginal prostaglandins are recommended for induction of labour. Intravaginal prostaglandin
E2 are used in the form of pessaries, vaginal tablets or gel. Vaginal low-dose misoprostol (25 μg, 6-hourly to
a maximum of 4 doses) is recommended for induction of labour. Oral misoprostol (25 μg, 2-hourly to a
maximum of 10 doses) is also recommended for induction of labour where the membranes have ruptured.
Misoprostol use is not recommended for women with previous caesarean section. Misoprostol is a synthetic
analogue of PGE1. When given orally, it is rapidly absorbed by the gastrointestinal tract. It can also be
administered vaginally. The total systemic bioavailability of vaginally administered misoprostol is three
times greater than that of orally administered misoprostol. It may be used both for cervical ripening and
induction of labour.

PROTOCOL FOR INDUCTION OF LABOUR USING 25μg VAGINAL MISOPROSTOL TABLET:

For induction of labour using vaginal misoprostol, use a 25μg tablet/pessary inserted into the posterior
fornix every six (6) hours
1. Confirm that there is an appropriate indication for induction of labour.
2. Confirm that there is no contraindication to induction of labour e.g. previous Caesarean section,
myomectomy, malpresentation, foetus currently in breech presentation or transverse lie etc.
3. Admit the client.
4. Administration: insert 1 tablet of 25 μg of misoprostol in the posterior fornix stat. Repeat this dose
every six (6) hours for a maximum of four (4) doses.
5. Once contractions start, perform vaginal examination to confirm labour
6. Monitor labour with partograph
 7. If the mother has not gone into labour 6 hours after the 4th dose, critically reappraise and check the
Bishop’s score.
a. If the Bishop’s score is favourable (≥ 6) perform ARM, augment with oxytocin and continue
charting the partograph observations.
b. If the Bishop’s score is poor, consider allowing the patient to rest for 24 hours, then restart the
regimen or deliver by Caesarean section depending on the indication for induction and urgency of
delivery.
c. If the second cycle of oral misoprostol fails, deliver by Caesarean section.
Note:
 Low-dose vaginal misoprostol (25 μg, 6-hourly) is recommended for induction of labour.
 When prostaglandins are used, close monitoring of the woman and foetus should begin immediately
after administration of the drug.
 Remove any remaining tablet from the vagina
 In case of uterine hyperstimulation stop further misoprostol and assess need for tocolysis e.g. using
salbutamol, terbutaline, magnesium sulphate etc.

PROTOCOL FOR INDUCTION OF LABOUR WITH ORAL MISOPROSTOL SOLUTION

Confirm that there is an appropriate indication for induction of labour.
1. Confirm that there is no contraindication to induction of labour e.g. previous Caesarean Section,
myomectomy, hysterotomy, foetus currently in breech presentation or transverse lie).
2. Induction of labour should be commenced in the ward i.e. admit the client
3. Preparation of solution should be done in the ward
4. Preparation: Dissolve one tablet of misoprostol 200mcg in 200mls of drinking water
5. Administration: Give 25mls of the prepared solution stat, then give 25mls every two hours to a
maximum of ten (10) doses
6. Once contractions start, vaginal examination should be done to confirm labour
7. Monitor labour with partograph
8. If the mother has not gone into labour two hours after the 10th dose, critically reappraise and check the
Bishop’s score. If the Bishop’s score is favourable (≥ 6) do ARM, augment with oxytocin and continue
observations. If the Bishop’s score is poor consider allowing the patient to rest for 24 hrs, then start
again, or caesarean section depending on the indication for induction and urgency of delivery.
Note:
 When prostaglandins are used, close monitoring of the woman and fetus should begin immediately
after administration of the drug.
 In case of uterine hyper stimulation stop further misoprostol and assess need for tocolysis with
salbutamol, terbutaline, ritodrine, magnesium sulphate etc.
 The prepared oral solution must be used within 24 hours
Oxytocin
If prostaglandins are not available, intravenous oxytocin alone should be used for induction of labour. It
should however be used with caution and careful observation due to risk of hyper stimulation and foetal
distress and rarely uterine rupture. When oxytocin infusion results in good labour pattern, maintain the same
rate until delivery.
Oxytocin is the most commonly used drug for induction of labour. Oxytocin may be used after ripening of
the cervix using prostaglandins or other mechanical methods. If the bishop’s score is favourable (≥ 6) labour
is usually successfully induced with oxytocin alone. A lower score necessitates ripening.
Prior to administering oxytocin one needs to review for indications and rule out any contraindications to
induction. Women receiving oxytocin must be carefully monitored throughout labour with special focus on
maternal pulse, blood pressure, contractions and foetal heart rate.

In areas without an infusion pump, oxytocin is delivered as follows:

1. Infuse oxytocin 2.5 units in 500mls of dextrose or normal saline at 10 drops per minute. (this is
approximately 2.5mIU /min).
2. Increase the infusion rate by 10 drops per minute (dpm) every 30 minutes until the patient has a good
contraction pattern of 3 contractions in 10 minutes each lasting 40 seconds. Maintain this rate until
delivery
3. If a good contraction pattern is not established with an infusion rate of 60dpm, increase the oxytocin
concentration to 5units in 500 mls of dextrose or normal saline and adjust the rate to 30 dpm
4. Increase the infusion rate by10 dpm every 30 minutes until a good contraction pattern is established or
the maximum of 60dpm is reached.
5. If a good contraction pattern is still not reached: in multigravida and in women with a previous scar, the
induction has failed and delivery should be by Caesarean section. In primigravida, one can increase the
concentration of oxytocin to 10 units in 500 mls of dextrose or saline. If good contractions are not
established with the maximum dose, deliver by caesarean section

In areas where there is an infusion pump:

Oxytocin is prepared for use by placing 10 U in 1 L of isotonic intravenous solution to achieve a
concentration of 10 mU per mL. Because severe hypotension can occur, a controlled infusion device must be
used to determine its rate. It can be administered as a continuous infusion or in "pulsed" doses. Continuous
infusions usually start with a dosage of 0.5 to 2.5 mU per minute, which is increased at the same increment
every 15 to 60 minutes. The effect is noted within three to five minutes, and a steady state is achieved within
15 to 30 minutes.

The advantages of Oxytocin are:

i) it doesn’t cross the placental barrier;
ii) it is potent and easy to titrate,
iii) it has a short half-life (one to five minutes) and
iv) it is generally well tolerated.

However, because oxytocin is close to vasopressin in structure, it has an antidiuretic effect when given in
high dosages (40 mU per minute); thus, water intoxication is a possibility in prolonged inductions. Uterine
hyper stimulation and uterine rupture can also occur. When the resting uterine tone remains above 20 mm
Hg, uteroplacental insufficiency and fetal hypoxia can result.

If a worrisome FHR occurs during induction, the oxytocin dosage can usually be lowered rather than
stopped completely. This allows the fetus to recover without unnecessarily slowing the entire labor. In
emergency situations, the infusion can be stopped. Minor FHR abnormalities such as variable decelerations
or lack of accelerations can be corrected by changing the mother's position, administering oxygen and
increasing intravenous fluid administration.
Possible Complications of Oxytocin Use
 Hypertonic uterine contraction causing foetal distress
 Tetanic and tumultuous contractions, which can result in abruptio placenta
 Birth injury due to rapid expulsion of the baby
 Mother may develop hypertension with frontal headache
 Uterine rupture
Surgical Induction (Amniotomy)
Amniotomy alone is not recommended for induction of labour.
In the case of an uncomplicated pregnancy, a sweep of the membranes is an effective method of inducing
labour. After a vaginal examination, the index finger is swept through the cervical os to detach foetal
membranes from the deciduas. The action produces prostaglandin.
Sweeping membranes is recommended for reducing formal induction of labour. However, maternal
discomfort and bleeding associated with the procedure should be balanced with the anticipated benefits.
Since the interval between intervention and result (i.e. sweeping membranes and initiation of labour) can be
longer than with formal methods of induction of labour, this intervention would be suitable for non-urgent
indications for pregnancy termination.
Amniotomy is an Artificial Rupture of the Membranes (ARM), which is carried out to induce labour when
the cervix is favourable. A well fitting presenting part is essential to avoid prolapse of the cord or rupture of
the membranes. Allow the descent of the presenting part to the cervical os. This raises the level of
prostaglandin which stimulates strong contractions to hasten labour. This method of induction may be
combined with oxytocin drip and this is referred to as combined method. This method has likelihood of
delivery within 12 hours, requires less analgesia and reduces the risk of Post PartumHaemorrhage (PPH).
Hazards Associated with Artificial Rupture of Membranes (ARM)
 Intrauterine infection due to contaminated instruments
 Cord prolapse
 Early foetal heart deceleration
 Bleeding due to vasa or placenta previa
Risks associated with induction of labour
1. Premature delivery
2. Sepsis
3. Foetal distress
4. Failed induction and Caesarean section
5. Hyper stimulation
6. Umbilical cord accidents
7. Uterine rupture