Despite attempts to convince us that induction of labour reduces the caesarean section rate, those of us who have worked within hospitals know differently. Experience tells us that induction of labour poses a real threat to a woman’s chance of having an unassisted vaginal birth. Sometimes, the potential benefits of induction outweigh this and other risks, but I know many midwives, doctors and others who think that the current induction rate is far too high.
I’m always sweeping the literature for snippets and studies that relate to the question of how we can help more women to have the birth they want. And, with more online courses coming up, I was interested to see the publication of research from Sweden (Ekéus & Lindgren 2016) which looked specifically at the impact of induction on unplanned caesarean and vacuum extraction.
Even better, the researchers controlled for medical complications. That allows us to see whether having a complication changes the situation for women. This is retrospective research, so it has pros and cons in relation to what we are able to gather from it, but we know from some of the systematic reviews of the randomised controlled trials in this area that the data from these are subject to human interpretation and their results are not always the best way of seeing what is happening in reality.
The Swedish research includes data from over a million births. And it confirms that, for most women, having labour induced means they are two or three times more likely to have an unplanned caesarean section. The exceptions to this were women who had already had a baby whose labours were induced early because they had a problem, but this is a fairly specific group, and the majority of women who undergo induction do not fall into this group. Women having their labour induced were also more likely to have a vacuum extraction, although the chance of this happening was less than the chance of their being told they needed a caesarean section.
The data are particularly stark for women who do not have a medical complication, which includes those whose labours are induced simply because they have reached a certain point in pregnancy. For these women, having their labour induced in weeks 39, 40 or 41 of their pregnancy meant they were three times more likely to end up with a caesarean section than the women whose labour began spontaneously.
I am increasingly passionate about getting details about this kind of data out there for midwives, doctors, birth folk and women, through workshops and courses as well as through my website. We need to have good information to discuss with women and their families, we need to be confident in sharing this information and we need to pool our ideas about how we can bring about change. And yes, we also need to think about how we can help those women who truly do need interventions and consider whether there are things we can do to increase their chance of a normal birth.
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Ekéus C and Lindgren H (2016). Induced Labor in Sweden, 1999–2012: A Population-Based Cohort Study. Birth. Early online, DOI: 10.1111/birt.12220
Background: Previous studies show contradictory results about the impact of induced labor on the cesarean delivery rate and few studies have investigated the risk of vacuum extraction subsequent to induced labor. The aims of the present study were to describe the rate of induced labor in Sweden from 1999 to 2012, and to assess the risk of unplanned cesarean delivery and vacuum extraction after induced labor in relation to medical complications and length of gestation.
Methods: A register-based cohort study was conducted, including 1,078,536 women with spontaneous or induced onset of labor who gave birth by noninstrumental vaginal delivery, unplanned cesarean delivery, or vacuum extraction in gestational week 37 + 0 to 41 + 6. Logistic regression was used to study the association between induced labor and instrumental delivery.
Results: The rate of induced labor increased from 7.7 to 12.9 percent among primiparous and from 7.5 to 11.8 percent among multiparous women. Induced labor was associated with 2–3 times greater risk of unplanned cesarean delivery among all women, except multiparas in gestational week 37–38, and with a 20–50 percent higher risk of vacuum extraction after the adjustment for confounding factors. Among women without a recognized medical complication, induced labor was associated with a threefold increased risk of cesarean delivery in gestational week 39–41 and a 40 percent increase in gestational week 37–38 compared with women with spontaneous onset of labor.
Conclusions: The proportion of induced labors increased substantially during the 14-year study period and was associated with an increased risk of both cesarean delivery and vacuum extraction, even in women without a documented medical complication. The increased risk of instrumental delivery should be taken into account when counseling about the risks and benefits of induced labor.