What is induction of labor?
Induction of labor is the use of medications or other methods to
contractions before the natural onset of labor in order to have a vaginal
Why is induction of labor done?
Induction of labor is usually considered
when continuing the pregnancy would increase the risks to the baby or mother without giving any benefit to either.
Some Medical Reasons for Induction [1-3]
Nonmedical (Elective) Reasons for Induction
The National Institute of Child Health and Human
Development, Society for Maternal-Fetal Medicine, and American College of
Obstetricians and Gynecologists recommend
- The mother is uncomfortable or anxious
- Partner soon leaving town (including
- Family in town
mother has rapid deliveries.
- Mother lives a long distance from the hospital,
Labor induction should be performed only for medical
- If done for nonmedical indications, the gestational age should be 39 weeks or more, and the
cervix should be favorable (Bishop score 8 or higher), especially in a woman
who has never given birth (nulliparous).
- Cervical ripening may be considered when there is a
medical indication for induction.
Since inductions without medical indication should not be done with an unripe
cervix, cervical ripening would not be an option
What is a Bishop Score and what is
a favorable (ripe) or an unfavorable (unripe) cervix?
The Bishop Score (also known as Pelvic Score) is the most
commonly used method to assess the readiness of the cervix for induction of
labor. The Bishop Score gives points to 5 components of the pelvic examination
dilation, effacement of the cervix, station of the fetus, consistency of the
cervix, and position of the cervix.
5 -6 cm
-1 or 0
See Bishop Score
Calculator for more on the Bishop Score
If the Bishop score is 8 or greater the chances of having a vaginal delivery are
good and the cervix is said to be favorable or "ripe" for induction.
Bishop score is 6 or less the chances of having a vaginal delivery are low and
the cervix is said to be unfavorable or "unripe" for induction.
What is cervical ripening?
Cervical ripening is the process where the cervix becomes ready for labor
by becoming softer , thinner and opening (dilating) during the last few weeks of
pregnancy. Medications or mechanical dilators are sometimes used to artificially
ripen the cervix before induction to make the cervix more favorable and a
vaginal delivery more likely.
What are some methods that are used to ripen the cervix?[1,
What are some methods that can be used to induce
Oxytocin is a hormone that is made in the brain and causes the uterus to
contract Oxytocin is released naturally into the blood
during labor, nipple stimulation, and sex.
Synthetic oxytocin (Pitocin) is used to begin or stimulate labor 
Amniotomy also known as artificial rupturing of the membranes (AROM) or
breaking your water. The procedure is sometimes done using a plastic
device that looks like a crochet needle (AmniHook® ) to open the
water bag that surrounds the baby. Amniotomy used alone for inducing
labor can be unpredictable . Amniotomy is more effective in speeding up the
progress of labor when used with oxytocin. [31,32]
What are the risks of inducing labor?
Failed induction was found to be more likely with an unfavorable cervix in a
woman who has never given birth (nulliparous) in some but not all studies
The induction may fail and you will need to be delivered by cesarean
The NICHD, SMFM, and ACOG recommend
"The diagnosis of failed induction should only be made after an adequate
attempt. Failed induction is defined as failure to generate regular (eg, every 3
minutes) contractions and cervical change after at least 24 hours of oxytocin
administration, with artificial membrane rupture if feasible."
- Abnormal contraction pattern.
Prostaglandins and oxytocin may
cause contractions that last too long are too strong or are too close
together. The abnormal contractions can cause your baby's heart
rate to drop.
Cord prolapse 
The umbilical cord is the tube-like structure attached to your
developing baby's belly that supplies nutrients and oxygen to your baby.
Sometimes after the membranes have ruptured the baby's umbilical cord may
pass through the cervix (the opening of the uterus) in front of the head or
body of your baby. This called cord prolapse. Pressure on the
umbilical cord can decrease the blood flow to the baby causing the baby's
heart rate to drop.
- Bleeding and Pain 
Bleeding and pain may be caused by mechanical methods such as the foley
catheter or dilators.
An increased risk for maternal and neonatal infections has been reported
in connection with the use mechanical devices
Uterine rupture is a tear through the entire thickness of the uterine wall.
Uterine rupture usually occurs in a woman who has had an operation on her uterus such as a
cesarean section, myomectomy (removal of fibroids) , or metroplasty (repair of
uterine malformation). Although uterine rupture may occur even with
natural labor the chances of uterine rupture occurring iare greater if
prostaglandins are used to induce
Amniotic Fluid Embolism [19-21]
Amniotic fluid embolism (AFE ) is a rare unpredictable condition in which
amniotic fluid , the fluid around the baby, enters the mother's blood stream and
causes heart and lung failure with uncontrolled bleeding. AFE has been associated
with advanced maternal age, polyhydramnios, cervical laceration, uterine
rupture, placenta previa , abruption, eclampsia, fetal distress , cesarean
delivery, and in some studies induction of labor.
Can you be induced if you are having a vaginal birth after
cesarean delivery (VBAC)?[22-36]
Induction of labor
for medical reasons may be an option for women who wish to attempt a vaginal
birth after having had a cesarean delivery (VBAC) . If you are attempting a VBAC
you should know that you are more likely to have a cesarean section with
induction of labor. In addition induction of labor with oxytocin or
prostaglandins has been associated with an increased risk of uterine rupture in
women attempting VBAC in some studies. ACOG recommends "Misoprostol should
not be used for third trimester cervical ripening or labor induction in patients
who have had a cesarean delivery or major uterine surgery." The Society of
Obstetricians and Gynaecologists of Canada. (SOGC) considers cervical ripening
with a transcervical foley catheter a safer option in women planning VBAC.
However, the risk of uterine rupture is not entirely eliminated with the use of
the Foley catheter .
Reviewed by Mark Curran, M.D. FACOG
ACOG Practice Bulletin No. 107: Induction of labor.ACOG
Committee on Practice Bulletins -- Obstetrics.Obstet Gynecol. 2009 Aug;114(2 Pt
1):386-97. doi: 10.1097/AOG.0b013e3181b48ef5. PMID:
2. Medically indicated late-preterm and
early-term deliveries. Committee Opinion No. 560. American College of
Obstetricians and Gynecologists. Obstet Gynecol 2013;121:908–10.PMID
3. Definition of term pregnancy. Committee
Opinion No. 579. American College of Obstetricians and Gynecologists. Obstet
Spong CY, et. al. Preventing the first cesarean delivery: summary of a joint
Eunice Kennedy Shriver National Institute of Child Health and Human Development,
Society for Maternal-Fetal Medicine, and American College of Obstetricians and
Gynecologists Workshop. Obstet Gynecol. 2012 Nov;120(5):1181-93. doi
http://10.1097/AOG.0b013e3182704880. PMID: 23090537
5. Bishop EH Pelvic scoring for elective induction.Obstet
Gynecol. 1964 Aug;24:266-8. PMID: 14199536
6. Pitocin (oxytocin) . Package insert.
7. Cytotec (misoprostol) tablet
8. Cervidil (dinoprostone) insert, extended release
9. Prepidil (dinoprostone) gel
10. WHO recommendations for induction of labour . World Health Organization 2011
ISBN 978 92 4 150115 6
11. Alfirevic Z, Weeks A. Oral misoprostol for induction of labour. Cochrane
Database Syst Rev. 2006 Apr 19;(2):CD001338.
12. Kundodyiwa TW, et. al., Low-dose oral misoprostol for induction of labor: a
systematic review. Obstet Gynecol. 2009 Feb;113(2 Pt 1):374-83. PMID:
13. Jozwiak M, et. al., Cervical ripening with Foley catheter for induction of
labor after cesarean section: a cohort study.
Acta Obstet Gynecol Scand. 2013 Dec 16. doi: 10.1111/aogs.12320. PMID:
14.Jozwiak M, et. al., PROBAAT Study Group.Foley catheter versus vaginal
prostaglandin E2 gel for induction of labour at term (PROBAAT trial): an
open-label, randomised controlled trial.
Lancet. 2011 Dec 17;378(9809):2095-103. PMID:
15 Mozurkewich EL, et. al., Methods of induction of labour: a systematic review.
BMC Pregnancy Childbirth. 2011 Oct 27;11:84.4 PMID:
16. Cromi A, et. al., A randomized trial of preinduction cervical ripening:
dinoprostone vaginal insert versus double-balloon catheter. Am J Obstet Gynecol.
17. Lyndon-Rochelle M, et. al.,
Risk of uterine rupture during labor among women with a prior cesarean delivery.
N Engl J Med. 2001 Jul 5;345(1):3-8.
18.ACOG Practice Bulletin No. 107: Induction of labor.
ACOG Committee on Practice Bulletins -- Obstetrics.Obstet Gynecol. 2009
Aug;114(2 Pt 1):386-97. .PMID:
Abenhaim HA, et. al.,Incidence and risk factors of amniotic fluid embolisms: a population-based study
on 3 million births in the United States.Am J Obstet Gynecol. 2008 Jul;199(1):49.e1-8. doi: 10.1016/j.ajog.2007.11.061.
Knight M, et. al. UK Obstetric
Surveillance System.Incidence and risk factors for amniotic-fluid embolism.Obstet Gynecol. 2010 May;115(5):910-7.
Kramer MS, et. al., Maternal Health Study Group of the
Canadian Perinatal Surveillance System.Amniotic-fluid embolism and medical induction of labour: a retrospective,
population-based cohort study.
Lancet. 2006 Oct 21;368(9545):1444-8.PMID: .
22. ACOG Practice bulletin no. 115: Vaginal birth after previous cesarean delivery.
American College of Obstetricians and Gynecologists. Obstet Gynecol. 2010
Aug;116(2 Pt 1):450-63. PMID:
Guidelines for Vaginal Birth After Previous Caesarean Birth. No 155 (Replaces
guideline No 147), Society of Obstetricians and Gynaecologists of Canada J
Obstet Gynaecol Can 2005;27(2):164–174
Landon MB, Let. al., The MFMU Cesarean Registry: factors affecting the success
of trial of labor after previous cesarean delivery.National Institute of Child
Health and Human Development Maternal-Fetal Medicine Units Network.
Am J Obstet Gynecol. 2005 Sep;193(3 Pt 2):1016-23.PMID: 16157104
Hochler H, et. al., Safety of trial of labor after cesarean delivery in
Obstet Gynecol. 2014 Feb;123(2 Pt 1):304-8. PMID: 24402589
Grobman WA, et. a.l, Outcomes of induction of labor after one prior cesarean.
Obstet Gynecol. 2007 Feb;109(2 Pt 1):262-9.
27. Jozwiak M, vet .al., Cervical ripening with Foley catheter for induction of
labor after cesarean section: a cohort study.Acta Obstet Gynecol Scand. 2013 Dec 16. doi: 10.1111/aogs.12320.
Bujold E, et . al., Cervical ripening with transcervical foley catheter and the
risk of uterine rupture.Obstet Gynecol. 2004 Jan;103(1):18-23.PMID: 14704239
29. Wing S. Induction of Labor In: Queenan JT, Hobbins JC, Spong eds CY
Protocols for High-Risk Pregnancies. 5th ed Blackwell Publishing Ltd. 2010 : 142
30. Bokström H, Wiqvist N. Prostaglandin release from human cervical tissue in
the first trimester of pregnancy after preoperative dilatation with hygroscopic
tents. Prostaglandins. 1995 Oct;50(4):179-88. PMID: 8848542
31. Smyth RM, et. al., Amniotomy for shortening spontaneous labour.Cochrane
Database Syst Rev. 2013 Jun 18;6:CD006167. doi: 10.1002/14651858.CD006167.pub4.
32. Wei S, et. al., Early amniotomy and early oxytocin for prevention of, or
therapy for, delay in first stage spontaneous labour compared with routine care.
Cochrane Database Syst Rev. 2013 Aug 7;8:CD006794. doi:
10.1002/14651858.CD006794.pub4. PMID: 23926074
33. National Collaborating Centre for Women's and Children's Health (UK).
Induction of Labour. London: RCOG Press; 2008 Jul. (NICE Clinical Guidelines,
No. 70.) 8, Complications of induction of labour. Available from:
Maslovitz S, et al. Complications of trans-cervical Foley catheter for labor
induction among 1,083 women.Arch Gynecol Obstet. 2010 Mar;281(3):473-7. PMID:
35. Ouzounian JG, et al. Vaginal birth after cesarean section: risk of uterine
rupture with labor induction. Am J Perinatol. 2011 Sep;28(8):593-6. doi:
10.1055/s-0031-1275386. Epub 2011 Mar 18.PMID: 21424988
36. Dekker GA, Risk of uterine rupture in Australian women attempting vaginal
birth after one prior caesarean section: a retrospective population-based cohort
BJOG. 2010 Oct;117(11):1358-65. doi: 10.1111/j.1471-0528.2010.02688.x. Epub 2010
Aug 17. Erratum in: BJOG. 2010 Dec;117(13):1672. PMID: 20716251
37. Darney BG, et. al., Elective induction of labor at term compared with
expectant management: maternal and neonatal outcomes. Obstet Gynecol. 2013
Oct;122(4):761-9. PMID: 24084532