Induction: An Annotated Bibliography

J. Christopher Glantz MD MPH (2003) Labor Induction Rate Variation in Upstate New York: What Is the Difference? Birth 30 (3), 168–174.
Research Conclusions: Labor induction rates are highly variable among and within hospitals. Delivery volume, population risk status, and differences in cesarean section rates did not explain this variation.

Irion O, Boulvain M. Induction of labour for suspected fetal macrosomia (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd.
Reviewers’ conclusions: Induction of labour for suspected fetal macrosomia in non-diabetic women did not appear to alter the risk of maternal or neonatal morbidity.

Boulvain M, Stan C, Irion O. Membrane sweeping for induction of labour (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd.
Reviewers’ conclusions: Routine use of sweeping of membranes from 38 weeks of pregnancy onwards does not seem to produce clinically important benefits. When used as a means for induction of labour, the reduction in the use of more formal methods of induction needs to be balanced against women’s discomfort and other adverse effects.

Alfirevic Z. Oral misoprostol for induction of labour (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd.
Reviewers’ conclusions: Oral misoprostol is an effective method for labour induction in the third trimester. However, the data on optimal regimens and safety are lacking. It is possible that effective oral regimens may have an unacceptably high incidence of complications such as uterine hyperstimulation and possibly uterine rupture.

Howarth GR, Botha DJ. Amniotomy plus intravenous oxytocin for induction of labour (Cochrane Review)
The reviewers found that using amniotomy plus oxytocin did result in fewer women having not given birth, and resulted in fewer instrumental deliveries. However, they caution that “Data on the effectiveness and safety of amniotomy and intravenous oxytocin are lacking.” For this reason they give no recommendations for this clinical practice.

Kavanagh J, Kelly AJ, Thomas J Breast stimulation for cervical ripening and induction of labour (Cochrane Review)
Although concerns about the quality of the studies reviewed prevent the researchers from drawing conclusions about the safety of breast stimulation for induction, they noted that breast stimulation “would appear beneficial in terms of a reduction in the number of women not in labour after 72 hours, and a reduction in postpartum haemorrhage.” They caution use of breast stimulation in high risk populations until more safety research is done.

Duff C, Sinclair M. Exploring the risks associated with induction of labour: a retrospective study using the NIMATS database. Northern Ireland Maternity System. Clin Exp Obstet Gynecol. 1996;23(1):41-7.
Induction of labour is a valuable obstetric procedure, providing obstetricians with the means to intervene should the health of the fetus be in jeopardy. Currently the most common reason for induction of labour is prolonged pregnancy, as obstetricians and midwives are concerned about the risks of postmaturity such as stillbirth, intrapartum asphyxia and birth trauma which are often associated with prolonged pregnancy (Lagrew & Freeman 1986). A retrospective comparative study was carried out in a large maternity unit to identify whether or not there was clinical evidence to support a policy of elective induction for post-term pregnancy. Three years’ data were extracted from the Northern Ireland Maternity System (NIMATS) by writing new queries to the system. These data on 3262 women who delivered during 1994-96 were analysed to compare the outcomes for women who were induced with women who delivered spontaneously. Although the findings from the study in many instances failed to demonstrate statistical significance between the groups they did however, have important clinical significance. For example, those women who were induced had a 5% higher rate of caesarean section, 17% higher rate of epidural analgesia and on average a greater estimated blood loss. Statistical significance was evident when the apgar scores of the infants were compared; those induced had lower Apgars at 1 minute (7. 78 in the induced group compared to 7.9 in the spontaneous group [P < 0.01]) and at 5 min (8.99 in the induced group compared to 9.05 in the spontaneous group [P < 0.02]).