Induction of labor

1. INDUCTION OF LABOR

2. Inductionof labor refers to the iatrogenic stimulation of uterine contractions before the
onset of spontaneous labor to accomplish vaginal delivery.
Augmentation of labor refers to increasing the frequency and improving the intensity of
existing uterine contractions in a patient who is in labor and not progressing adequately, in
order to accomplish vaginal delivery

3. INDICATIONS FOR INDUCTION OF LABOUR
• Prolonged pregnancy (usually offered after 41 completed weeks) (40 w+10d)
• PROM.
• Pre-eclampsia and other maternal hypertensive disorders
• FGR
• Diabetes mellitus
• Impending Fetal macrosomia
• Deteriorating maternal illness.
• Unexplained antepartum haemorrhage at term
• Twin pregnancy continuing beyond 38 weeks.
• Intrahepatic cholestasis of pregnancy.
• Maternal isoimmunization against red cell antigens.
• ‘Social’ reasons.

4. • In PPROM : between 34-37 if maternal and fetal status are stable and no chorioamnionitis
• In PROM : induction after 24 hours if spontaneous labor doesn’t start spontaneously
• In Hypertensive disorders of pregnancy (stable : not before 37 weeks )
• Preeclampsia : after 34 weeks if stable enough to be induced
• DM : 38 weeks
• GDM : 41 weeks if controlled and uncomplicated
• IUGR or SGA with normal doppler : 37
• Twins : Dichorionic diamniotic at 38

5. CONTRAINDICATIONS

6. • It is most successful when the cervix is ‘ ripe ’ at the time of labor induction
(favorable )
• Bishop score of 5 or more is inducible

8. OXYTOCIN
• This physiologic mechanism makes oxytocin more effective in augmenting labor than in inducing labor,
and even less successful as a cervical ripening agent
• Oxytocin is most often given intravenously
• The plasma half-life is short, estimated at 3 to 6 minutes, and steadystate concentrations are reached
within 30 to 40 minutes of initiation or dose change.
• Synthetic oxytocin is generally diluted by placing 10 units in 1000 mL of an isotonic solution
 Oxytocin should be increased at intervals not less than every 30 min
 Regardless of the regimen used, the target frequency of uterine contractions is three to five every 10
min

9. PROSTAGLANDINS
• PGE2 is used for induction of labor and cervical ripening (Dinoprostone)
• Side effects of all PG formulations and routes may include fever, chills, vomiting, and
diarrhea
• The various administration vehicles (tablet, gel, and timed-release pessary) appear to
be equally efficacious
• PG formulations of any kind should be avoided in women with a prior uterine scar
• Continuous fetal monitoring when contraction start
• Misoprostol (Cytotec) is a synthetic prostaglandin E1 analog available as
100 mcg and 200 mcg tablets and not recommended by the NICE guidline to be used
unless in case of IUFD

10. MECHANICAL METHODS
• The most common mechanical methods :
Stripping (or sweeping) of the fetal membranes
Amniotomy
Hygroscopic dilators within the endocervical canal
Balloon catheter placement above the internal cervical os (with or without infusion of extra-
amniotic saline).
 All of these methods likely work, at least in part, by causing the release of prostaglandin F2-
alpha from the decidua and adjacent membranes or prostaglandin E2 from the cervix
 Less cs, less side effects , low cost but Increase in the risk of maternal and neonatal infection

11. COMPLICATIONS OF INDUCTION OF LABOR
• Failure (most common complication )
• Rupture uterus
• Uterine overstimulation (more than 5 contractions per 10 mins )
• Abnormal fetal heart
• Water intoxication with oxytocin

12. • Induction of labor decreases the risk of CS in post date pregnancies
• In PROM at term, Induction within 24 hours reduces the risk of
chorioamnionitis, endometritis and NICU without increasing rates of
Caesarean section
• Induction of labor should be started in PROM after 24 hours if no
contraindication to waiting spontaneous labor