Induction of labour for post term pregnancy: An observational study

Please note that this is a searchable PDF derived via optical character recognition (OCR) from the original source document. As the OCR process is never 100% perfect, there may be some discrepancies between the document image and the underlying text.The aim of the study was to compare the 2 management protocols for postterm pregnancy; elective induction of labour at 42 weeks’ gestation and continuing the pregnancy with fetal monitoring while awaiting spontaneous labour. A retrospective observational study compared a cohort of 360 pregnancies where labour was induced with 486 controls. All pregnancies were postterm (>294 days) by an early ultrasound scan. Induction of labour was achieved with either prostaglandin vaginal pessaries or gel or forewater rupture and Syntocinon infusion. The control group consisted of women with postterm pregnancies who were not induced routinely and who usually had twice weekly fetal assessment with cardiotocography and/or ultrasound. Women who had their labour induced differed from those who awaited spontaneous labour. Nulliparas (OR 1.54; 95% CI 1.24-1.83) and married women (OR 1.76; 95% CI 1.45-2.06) were more likely to have their labour induced. There was no association between the type of caregiver and induction of labour. Induction of labour was associated with a reduction in the incidence of normal vaginal delivery (OR 0.63, 95% CI 0.43-0.92) and an increased incidence of operative vaginal delivery (OR 1.46; 95% CI 1.34-2.01). There was no difference in the overall rate of Caesarean section. There was no difference in fetal or neonatal outcomes. Parity had a major influence on delivery outcomes from a policy of induction of labour. Nulliparas in the induced group had worse outcomes with only 43% achieving a normal vaginal delivery (OR 0.78, 95% CI 0.65-0.95). In contrast for multiparas, the induced group had better outcomes with less Caesarean sections (OR 0.88, 95% CI 0.81-0.96). This retrospective observational study of current clinical practice shows that induction of labour for postterm pregnancy appears to be favoured by nulliparous married women. It suggests that induction of labour may improve delivery outcomes for multigravas but has an adverse effect for nulliparas.Unpublished1. FICO. International classification of diseases. Internat J Gynaecol Obstet 1980; 17: 634-640. 2. Baird D, Walker J, Thomson AM. The causes and prevention of stillbirths and first week deaths. J Obstet Gynaec Brit Emp 1954: 61: 433-448. 3. Keirse MJNC. Postterm pregnancy: New lessons from an unresolved debate. Birth 1993: N: 102-105. 4. Grant JM. Induction of labour confers benefits in prolonged pregnancy. Br J Obstet Gynaecol 1994: 101: 99-102. 5. Crowley P. Elective induction of labour at 41+ weeks gestation. In: Enkin MW, Keirse MJNC, Renfrew MJ, Neilson JP (eds.) Pregnancy and Childbirth Module of the Cochrane Database of Systematic Reviews, 1995 [updated 24 February 1995]. Available from BMJ Publishing Group: London. 6. Crowley R. Interventions to prevent, or improve outcome from, labour at or beyond term. In: Neilson JR, Crowther CA, Hodnett ED, Hofmeyr GJ, Keirse MJNC (eds.) Pregnancy and childbirth Module of the Cochrane Database of Systematic Reviews, [updated 04 March 1997]. Available in The Cochrane Library [database on disk and CDROM]. The Cochrane Collaboration; Issue 2. Oxford: Update Software; 1997. Updated quarterly. 7. The National Institute of Qtild Health and Human Development Network of Maternal-Fetal Medicine Units. A clinical trial of induction of labor versus expectant management in postterm pregnancy. Am J Obstet Gynecol 1994; 170: 716-723. 8. Hannah ME, Hannah WJ, Hellmann J, Hewson S, Milner R, Willan A. Induction of Labour as compared with serial antenatal monitoring in post term pregnancy. N Eng Med J 1992: 326: 1587-1592. 9. Keirse M. JNC Prostaglandin versus Oxytocin for Induction of Labour: In:Enkin MW, Keirse MJNC, Renfrew MJ, Neilson JP (eds.) Pregnancy and Childbirth Module of the Chochrane Database of Systematic Reviews. 1995 [updated 24 February 1995]. Available from BMJ Publishing Group: London. 10. Roberta LJ, Young KR. The management of prolonged pregnancy — an analysis of women’s attitudes before and after term. Br J Obstet Gynaecol 1991; 98: 1102-1106. 11. Cardozo L, Fysh J, Pearce JM. Prolonged pregnancy: the management debate. Br Med J Clin Res Ed. 1986; 293: 1059-1063