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]).
Bibliographical noteReference text: 1Anderson H.F., Johnson T.R.B., Flora J.D., Barclay M.L. (1981) Gestational age assessment. II. Prediction from combined clinical observations. American Journal of Obstetrics and Gynecology 140, 770770.
2Bakketeig L. & Bergsjo P. (1989) Post-term pregnancy: magnitude of the problem. In Effective Care in Pregnancy and Childbirth. (Chalmers I., Enkin M. & Keirse M.J.N.C., eds). Oxford University Press, Oxford, pp. 765–775.
3Battaglia C., Larocca E., Lanzani A., Coukos G., Genazzani A.R. (1991) Doppler velocimetry in prolonged pregnancy. Obstetrics and Gynaecology 77, 213 216.
4Bergsjo P., Gui-dan H., Su-qin Y., Zhi-zeng G., Bakkateig L.S. (1989) Comparison of induced versus non-induced labour in post term pregnancy. Alta Obstst Gynecol Scand 68, 683 687.
5Cardozo L., Fysh J., Pearce J.M. (1986) Prolonged pregnancy: the management debate. British Medical Journal 293, 1059 1062.
6Cooke P. (1997) Induction of Labour and Post-term Pregnancy. In Mayes' Midwifery: a Textbook for Midwives 12th edn. (Sweet B.R. & Tiran D., eds). Bailliere Tindall, London.
7Crowley P., O'Herlihy C., Boylan P. (1984) The value of ultrasound measurement of amniotic fluid Volume in the measurement of prolonged pregnancies. British Journal of Obstetrics and Gynaecology 91, 444 448.
8Data Protection Registrar (1997) Guidelines: the data protection act 1984. DPR, London.
9Department of Health (1993) Changing Childbirth. Report of the Expert Maternity Group. HMSO, London.
10El-Torkey M. & Grant J.M. (1992) Sweeping of the membranes is an effective method of induction of labour in prolonged pregnancy: a report of a randomised trial. British Journal of Obstetrics and Gynaecology 99, 455 458.
11Grant J.M. (1994) Induction of labour confers benefits in prolonged pregnancy. British Journal of Obstetrics and Gynaecology 101, 99 102.
12Hannah M.E., Hannah W.J., Hellman J., Hewson S., Milner R., Willan A. (1992) Induction of labour as compared with serial antenatal monitoring in post-term pregnancy. New England Journal of Medicine 326, 1587 1592.
13Huntingford P. (1985) Birth Right — The Parent's Choice. BBC, London.
14Johnston J.M., Harman C.R., Lange I.R., Manning M.D. (1986) Biophysical profile scoring in the management of the post term pregnancy: an analysis of 307 patients. American Journal of Obstetrics and Gynecology 154, 269 272.
15Jowitt M. (1993) Childbirth Unmasked. Wooller, Shropshire.
16Keirse M.J.N.C. & Chalmers I. (1989) Methods for inducing labour. In Effective Care in Pregnancy and Childbirth (Chalmers I., Enkin M. & Keirse M.J.N.C., eds). Oxford University Press, Oxford.
17Lagrew D.C. & Freeman R.K. (1986) Management of postdate pregnancy. American Journal of Obstetrics and Gynecology 154, 8 13.
18Levy V. (1990) The midwife's approach to management of the third stage of labour. In Intrapertum Care: a Research Based Approach. (Alexander J., Levy V. & Roch S., eds). Macmillan, London.
19Macer J.A., Macer C.L., Chan L.S. (1992) Elective induction versus spontaneous labour: a retrospective study of complications and outcome. American Journal of Obstetrics and Gynecology 166, 1690 1697.
20National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units (1994) Randomized trial of induction of labour versus expectant management in postterm pregnancy. American Journal of Obstetrics and Gynecology 170, 716 723.
21Newell R. (1997) Towards Clinical Effectiveness in Nursing. Clinical Effectiveness in Nursing 1, 1 2.
22NHS Executive (1996) Promoting Clinical Effectiveness: a Framework for Action in and Through the NHS. NHS Executive, London.
23Northern Ireland Maternity Unit Study Group (1994) Delivering Choice. DHSS, Northern Ireland.
24O'Connor R.A. (1994) Induction of labour — not how but why? British Journal of Hospital Medicine 52, 559 563.
25O'Driscoll K., Meagher D, Boylan P (1993) Active Management of Labour 3rd edn. Moseby, London.
26Pearce J.M. & McParland P.J. (1991) A comparison of doppler flow velocity waveforms, amniotic fluid columns and the nonstress test as a means of monitoring postdates pregnancies. Obstetrics and Gynaecology 77, 204 208.
27Phillips R. (1994) A need for research-based midwifery practice. British Journal of Midwifery 2, 335 338.
28Polgar S. & Thomas S.A. (1988) Introduction to Research in the Health Sciences. Churchill Livingstone, London.
29Roberts L.J. & Young K.R. (1991) The management of prolonged pregnancy — an analysis of womens attitudes before and after term. British Journal of Obstetrics and Gynaecology 98, 1102 1106.
30Smith L.P., Nagourney B.A., McLean F.H., Usher R.H. (1984) Hazards and benefits of elective induction of labour. American Journal of Obstetrics and Gynecology 148, 579 585.
31Tew M. (1995) Safer Childbirth. Chapman & Hall, London.
32Thomas P. (1996) Every Woman's Birthrights. Thorsons, London.
33Thomson A. (1989) Editorial. Research gives concrete reasons for our practice. Midwifery 5, 153 154.
34Wigton T.R. & Wolk B.M. (1994) Elective and routine induction of labour. The Journal of Reproductive Medicine 39, 21 26.
- induction of labour • risk management • Maternity System Data Sets • retrospective analysis • post-term pregnancy