When a technology is used as often as CTG monitoring is, it can be difficult to see the harms that arise as a consequence. These downstream effects become simply part of the normal conduct of maternity care. Yet the idea that “it’s just a CTG” and there are no harmful consequences is patently false. Today’s post explores some of the harmful consequences of CTG use – in particular the physical harms experienced by birthing women as a consequence of higher rates of surgical birth.
More caesarean sections
The first set of harms, and the one most visible within research, relate to the overuse of caesarean section that occurs when CTG monitoring is in use. When used during labour women considered to be at low risk are twice as likely to have a caesarean section, and women considered to be at high risk are 1.9 times more likely to have a caesarean section (Alfirevic et al., 2017). Women who have an admission CTG are also 1.2 times more likely to have a caesarean section (Devane, 2017). (Remember that for each of these groups of women, research shows no reduction in the risk of death or serious injury to the baby.)
It can be easy to dismiss caesarean section as simply an alternate way to give birth, and in doing so, overlook the harms that have been associated with caesarean section, both for the woman and for her baby (Wendland, 2007). While the rate at which complications occurs is generally low for any individual woman, when it is scaled up to population level it becomes more visible. For instance, in 2017 just over 100,000 Australian women had a caesarean section (Australian Institute of Health and Welfare, 2019). A complication impacting on just 1% of 100,000 women is an issue for 1,000 women.
Risks of caesarean section
Women who gave birth by caesarean section have increased rates of infection, haemorrhage, transfusion, and hysterectomy (Bodner et al., 2010; Declercq et al., 2007; Mascarello et al., 2017). They are more likely to be admitted to an intensive care unit, experience a longer duration of hospital stay, and be readmitted to hospital after discharge (Bodner et al., 2010; Declercq et al., 2007; Mascarello et al., 2017). Women are more likely to die following caesarean section than after vaginal birth (Esteves-Pereira et al., 2016; Fahmy et al., 2018; Mascarello et al., 2017).
In addition, women who have had a caesarean section are more likely to experience difficulty conceiving a future pregnancy (Keag et al., 2018), and when they conceive, face increased risks of complications in the subsequent pregnancy. These risks included miscarriage, stillbirth, placenta praevia, placenta accreta, uterine rupture, abruption, hysterectomy, and death (Cheng et al., 2016; Dekker et al., 2010; Hammad et al., 2013; Keag et al., 2018; O’Neill et al., 2013). Women who had a caesarean section and then had a hysterectomy later in life were more likely to experience surgical complications (Lindquist et al., 2017).
It is clear that caesarean section is not without consequence for birthing women. CTG use is also associated with increased rates of instrumental birth (forceps and vacuum extraction). There is also a 15% increase in the use of instrumental birth (vacuum extraction or forceps) (Alfirevic et al., 2017). Given that caesarean section is associated with the risk of additional complications for the mother, it is important to ask whether this holds true for instrumental birth as well.
Risks of instrumental birth
Instrumental birth has been associated with damage to women’s pelvic floor soft tissues. Higher rates of severe perineal trauma (involving disruption of the anal sphincter) have been reported both for vacuum assisted and forceps assisted births (Ampt et al., 2015; Hehir et al., 2013; Nilsson et al., 2016). Trauma to the levator ani muscle at its insertion on the pubic bone was also more frequent among women following instrumental birth (Garcia-Mejido et al., 2017; Kearney et al., 2010; Shek & Dietz, 2010).
Injuries to the perineum and pelvic floor have been linked to long term symptoms for women. Pain during sex 18 months postpartum was more common for women who gave birth with vacuum assistance than for women with non-instrumental vaginal birth (McDonald et al., 2015). Pelvic organ prolapse was more likely 16 to 24 years after forceps birth than non-instrumental vaginal birth (Volloyhaug et al., 2015).
In summary: there are clear short and long term physical harms to birthing women from the use of intrapartum CTG monitoring. This post is the first in a series exploring the risks related to CTG use. Stay tuned for more evidence- based information!
Alfirevic, Z., Devane, D., Gyte, G. M. L., & Cuthbert, A. (2017). Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews, 2(CD006066), 1-137. https://doi.org/10.1002/14651858.CD006066.pub3
Ampt, A. J., Patterson, J. A., Roberts, C. L., & Ford, J. B. (2015). Obstetric anal sphincter injury rates among primiparous women with different modes of vaginal delivery. International Journal of Gynecology and Obstetrics, 131(3), 260-264. https://doi.org/10.1016/j.ijgo.2015.06.025
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Hehir, M. P., O’Connor, H. D., Higgins, S., Robson, M. S., McAuliffe, F. M., Boylan, P. C., Malone, F. D., & Mahony, R. (2013). Obstetric anal sphincter injury, risk factors and method of delivery – an 8-year analysis across two tertiary referral centers. Journal of Maternal-Fetal and Neonatal Medicine, 26(15), 1514-1516. https://doi.org/10.3109/14767058.2013.791268
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Lindquist, S. A. I., Shah, N., Overgaard, C., Torp-Pedersen, C., Glavind, K., Larsen, T., Plough, A., Galvin, G., & Knudsen, A. (2017). Association of previous cesarean delivery with surgical complications after a hysterectomy later in life. JAMA Surgery, 152(12), 1148-1155. https://doi.org/10.1001/jamasurg.2017.2825
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Wendland, C. L. (2007). The vanishing mother: Cesarean section and & “evidence-based obstetrics”. Medical Anthropology Quarterly, 21(2), 218-233. http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=17601085&retmode=ref&cmd=prlinks