2. Induction of labour
An intervention designed to artificially initiate
uterine contractions leading to progressive
dilatation and effacement of the cervix and
birth of the baby.
3. Augmentation: stimulation of spontaneous
contractions that are considered inadequate
because of failure of progressive dilatation
and descent
4. Indications
1-Severe hypertensive disorders of pregnancy
2-Postterm pregnancy and macrosomia
3-Intra-uterine growth retardation
4-Oligohydramnios
5-Premature rupture of membranes
6-Chorioamnionitis
7-Some cases of antepartum hemorrhage
8-Diabetes mellitus with vasculopathy
6. Contraindications
1. Placenta previa and vasa previa
2-Abnormal fetal lie / presentation. e.g. transverse lie and breech presentation
3-Umbilical cord prolapse and fetal distress
4-Previous classical Cesarean section or other transfundal uterine surgery
5-Active herpes infection
6-Pelvic Structural abnormality
7-Invasive cervical cancer
8-Contraindicaton specific to the inducing drug used.
7. RISKS OF INDUCTION
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
9. Bishop Score
What’s most important in score?
Dilatation >effacement>station
– Unfavorable: score <6
Ripening agent indicated
– Favorable: score >8
Can induce
Probability of vaginal delivery with spontaneous labor
equals probability of vaginal delivery with IOL
11. II-Mechanical methods
2- Placement of Balloon Dilators after 42 weeks gestation:
A fluid filled balloon is inserted inside the cervix. The Balloon provide mechanical
pressure directly on the cervix which respond by ripening and dilation. A Foley catheter
(26 Fr) or specifically designed balloon devices can be used.
Technique of balloon placement:
1- After sterilization and draping, the catheter is introduced into the endocervix either by
direct visualization or blindly by sliding it over fingers through the endocervix into the
potential space between the amniotic membrane & the lower uterine segment.
12. 2- The balloon is inflated with 30 to 50 mL of normal saline and is retracted so
that it rests on the internal os.
3- Constant pressure may be applied over the catheter. e.g. a bag filled with 1 L of
fluid may be attached to the catheter end. An intermittent pressure may also
be exerted on the catheter end 2 -4 times per hour.
4-Catheter is removed at the time of rupture of membranes or may be expelled
spontaneously which indicate a cervical dilataion of 3-4 Centimeter.
13. -Stripping the membranes:
- Stripping the membranes mechanically dilates the cervix which releases prostaglandins. The
membranes are stripped by inserting the examining finger through the internal os & moving it in a
circular direction to detach the inferior pole of the membranes from the lower uterine segment.
- Risks include patient’s discomfort, infection, bleeding from undiagnosed placenta previa or low
lying placenta,and accidental ROM.
- The Cochrane reviewers concluded that stripping the membranes, when used as an adjunct,
decreases the mean dose of oxytocin needed and increases the rate of normal vaginal deliveries.
14. 2-Amniotomy - Technique:
-The FHR is recorded before the procedure.
-A pelvic examination is performed to evaluate the cervix & station of the
presenting part. The presenting part should be well fitted to the cervix.
-The membranes are identified and a kocher is inserted through the cervical os by
sliding it along the hand & fingers & membranes are ruptured.
-The nature of the amniotic fluid is recorded (clear, bloody, thick or thin,
meconium).
-The FHR is recorded after the procedure.
15. Risks of amniotomy:
1- Prolapse of the umbilical cord (0.5%)
2- Chorioamnionitis: Risk increases with prolonged induction delivery
interval
3- Postpartum hemorrhage: Risk is doubled compared with women with
spontaneous onset of labor
4- Rupture of vasa previa
5- Neonatal hyperbilirubinemia
16. IV-Pharmacologic Induction of Labor
1-Prostaglandin E2: (dinoprostone): It is inserted vaginally . It acts on
the cervical connective tissue and relaxes muscle fibres of the cervix.
it should only be administered at hospital and the patient is expected
to stay recumbent and monitored, at least, for the first 30 minutes after
insertion. Contractions usually start within 60 minutes of commencing
induction and peak within 4 hours. If optimal response is not achieved
by 6 hours, another dose can be administered. The maximum allowed
dose is 3 doses be administered per 24 hours.
17. 2-(Cytotec)
Route of administration: Oral, vaginal and
sublingual route for induction. Rectal route is
used to prevent and treat postpartum hemorrhage.
18. (Cytotec) is a synthetic PGE1 analog that has been found to be a safe and
inexpensive agent for cervical ripening.
-Clinical trials indicate that the safe optimal dose and dosing interval is
25 mcg intravaginally every 4-6 hours. A maximum of 6 doses was
suggested. Higher doses or shorter dosing intervals are associated
with a higher incidence of side effects, especially hyperstimulation
syndrome.
-Misoprostol should not be used in women with previous CS because of
increased rates of uterine rupture
19. 3-Oxytocin
It is given by IV infusion using an automated
pump. Oxytocin has many advantages: it is potent
and easy to titrate, has a short half-life (one to
five minutes) and is well tolerated.
20. Oxytocin dosage
:high-dose(4~6mU/min) vs low-dose (0.5~1.5
mU/min)
- low-dose → 1mU/min, interval 20 mins
high-dose → 6mU/min, interval 20 mins
Max 42mU/min
if hyperstimulation, reduce 3mU/min
21.
22. Side effects of oxytocin use:
1-Uterine hyperstimulation and subsequent FHR abnormalities.
2-Abruptio placentae and uterine rupture.
3-Water intoxication may occur with high concentrations of oxytocin
infused with large quantities of hypotonic solutions. Therefore;
prolonged administration with doses higher than 40 mu of oxytocin
per minute and infusion of fluids in any 10 hours should not excced
1500 ml. A rapid intravenous injection of oxytocin may cause
hypotension.
23. References
1-Smith CA, Crowther CA. Acupuncture for induction of labour. Cochrane Database Syst
Rev 2002;2:CD002962
2-Lin A, Kupferminc M, Dooley SL. A randomized trial of extra-amniotic saline infusion
versus laminaria for cervical ripening. Obstet Gynecol 1995; 86(4 part 1):545-9.
3-Rouben D, Arias F. A randomized trial of extra-amniotic saline infusion plus intracervical
Foley catheter balloon versus prostaglandin E2 vaginal gel for ripening the cervix and
inducing labor in patients with unfavorable cervices. Obstet Gynecol 1993;82:290-4
4-Sherman DJ, Frenkel E, Pansky M, Caspi E, Bukovsky I, Langer R. Balloon cervical
ripening with extra-amniotic infusion of saline or prostaglandin E2: a double-blind,
randomized controlled study. Obstet Gynecol 2001;97:375-80. .
24. -Goldman JB, Wigton TR. A randomized comparison of extra-amniotic saline infusion and
intracervical dinoprostone gel for cervical ripening. Obstet Gynecol 1999;93:271-4.
6-Guinn DA, Goepfert AR, Christine M, Owen J, Hauth JC. Extra-amniotic saline,
laminaria, or prostaglandin E(2) gel for labor induction with unfavorable cervix: a
randomized controlled trial. Obstet Gynecol 2000;96:106-12.
7-Foong LC, Vanaja K, Tan G, Chua S. Membrane sweeping in conjunction with labor
induction. Obstet Gynecol 2000;96:539-42.
8-Lydon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during
labor among women with a prior cesarean delivery. N Engl J Med 2001;345:3-8.
9-Hofmeyr GJ, Gulmezoglu AM. Vaginal misoprostol for cervical ripening and induction of
labour. Cochrane Database Syst Rev 2002;2:CD000941.
