There are a number of serious health complications associated with post-term or prolonged pregnancy, for both women and their unborn babies. This article discusses methods of inducing labour in women who experience prolonged pregnancy.
The most significant implication of a prolonged pregnancy is the increased risk of intra-uterine fetal death (Humphrey & Tucker, 2009). Prolonged pregnancy also increases the risk of oligohydramnios, lowered placental perfusion and the need for neonatal intensive care (Raatikainen, Harju, Hippelainen & Heinonen, 2010). While induced labour is considered to be more painful than labour which occurs spontaneously, research has concluded that induction of labour “completed at 41 weeks or beyond [is]associated with fewer perinatal deaths” (Gulmezoglu, Crowther & Middleton, 2009; Joanna Briggs Institute, 2010). Induction is therefore routinely recommended to post-term women.
An amniotomy or ‘membrane sweeping’ is the primary non-pharmacological method of labour induction offered to post-term women (Joanna Briggs Institute, 2010). An amniotomy involves the mechanical rupturing of the fetal membranes to allow the baby’s head to descend firmly onto the cervix, thereby increasing the natural production of prostaglandins and, often, causing the commencement of active contractions (Boulvain, Stan & Irion, 2010). Research suggests that amniotomy results in lower rates of caesarian births and meconium production (a foetal stress indicator) in post-term pregnancies than many other methods of induction (Joanna Briggs Institute, 2010).
However, amniotomy is an uncomfortable procedure, may lead to an increased risk of infection and is not always successful in promoting labour in post-term women (National Institute for Clinical Excellence, 2010/2). There are a range of pharmacological methods of induction that may also be suggested to post-term women. Synthetic prostaglandins, in the form of a vaginal pessary or cervical gel, have been shown to effectively induce labour in some women (Joanna Briggs Institute, 2010). The onset of labour may be further promoted through the intravenous administration of the hormone oxytocin (Howarth & Botha, 2010).
The midwife should support a post-term woman in making an informed decision regarding the induction of her labour by thoroughly discussing each of these different options and seeking collaborative referral where necessary (National Institute for Clinical Excellence, 2010/2).
Boulvain, M., Stan, C.M. & Irion, O. (2010). Membrane sweeping for induction of labour. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD000451.pub2; Gulmezoglu, M., Crowther, C.A. & Middleton, P. (2009). Induction of labour for improving birth outcomes for women at or beyond term. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD004945.pub2; Howarth, G. & Botha, D. J. (2010). Amniotomy plus intravenous oxytocin for induction of labour. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD003250; Humphrey, T. & Tucker, J.S. (2009). Rising rates of obstetric interventions: exploring the determinants of induction of labour. Journal of Public Health, 31(1), 88-94. Retrieved from http://search.ebscohost.com.ezp01.library.qut.edu.au/login.aspx?direct=true&site=dynamed&id=AN+411304; Joanna Briggs Institute. (2010). Labour: induction [Evidence based recommended practice]. Retrieved from http://www.joannabriggs.edu.au; National Institute for Clinical Excellence. (2010/2). Induction of labour [Evidence based recommended practice]. Retrieved from http://www.nice.org.uk/nicemedia/live/12012/41255/41255.pdf; Raatikainen, K., Harju, M., Hippelainen, M. & Heinonen, S. (2010). Prolonged pregnancy is associated with a greater risk of adverse outcomes. Fertility and Sterility, 94(3), 1148-1151. doi: 10.1016/j.fertnstert.2009.10.058.