Exploring the risks associated with induction of labour: a retrospective study using the NIMATS database

Induction of labour is a valuable obstetric procedure, providing obstetrici ans with the means to intervene should the health of the fetus be in jeopar dy. Currently the most common reason for induction of labour is prolonged p regnancy, as obstetricians and midwives are concerned about the risks of po stmaturity such as stillbirth, intrapartum asphyxia and birth trauma which are often associated with prolonged pregnancy (Lagrew & Freeman 1986). A re trospective 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 extracte d from the Northern ireland Maternity System (NIMATS) by writing new querie s 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 inst ances failed to demonstrate statistical significance between the groups the y did however, have important clinical significance. For example, those wom en 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. S tatistical significance was evident when the apgar scores of the infants we re compared; those induced had lower apgars at 1 minute (7.78 in the induce d 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]).