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).
Risks of instrumental birth
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.
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…
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!
References
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
Australian Institute of Health and Welfare. (2019). Australia’s mothers and babies 2017 in brief. https://www.aihw.gov.au/reports/mothers-babies/australias-mothers-and-babies-2017-in-brief/contents/table-of-contents
Bodner, K., Wierrani, F., Grünberger, W., & Bodner-Adler, B. (2010). Influence of the mode of delivery on maternal and neonatal outcomes: a comparison between elective cesarean section and planned vaginal delivery in a low-risk obstetric population. Archives of Gynecology and Obstetrics, 283(6), 1193-1198. https://doi.org/10.1007/s00404-010-1525-y
Cheng, H. C., Pelecanos, A., & Sekar, R. (2016). Review of peripartum hysterectomy rates at a tertiary Australian hospital. Australian and New Zealand Journal of Obstetrics and Gynaecology, 56(6), 614-618. https://doi.org/10.1111/ajo.12519
Declercq, E. R., Barger, M., Cabral, H. J., Evans, S. R., Kotelchuck, M., Simon, C., Weiss, J., & Heffner, L. J. (2007). Maternal outcomes associated with planned primary cesarean births compared with planned vaginal births. Obstetrics & Gynecology, 109(3), 669-677. https://doi.org/10.1097/01.AOG.0000255668.20639.40
Dekker, G. A., Chan, A., Luke, C. G., Priest, K., Riley, M., Halliday, J., King, J. F., Gee, V., O’Neill, M. J., Snell, M., Cull, V., & Cornes, S. (2010). Risk of uterine rupture in Australian women attempting vaginal birth after one prior caesarean section: a retrospective population-based cohort study. 117(11), 1358-1365. https://doi.org/10.1111/j.1471-0528.2010.02688.x
Devane, D., Lalor, J. G., Daly, S., McGuire, W., Cuthbert, A., & Smith, V. (Eds.). (2017). Cardiotocography versus intermittent auscultation of fetal heart on admission to labour ward for assessment of fetal wellbeing. Cochrane Database of Systematic Reviews, 1(CD005122), 1-46. https://doi.org/10.1002/14651858.CD005122.pub5.
Esteves-Pereira, A. P., Deneux-Tharaux, C., Nakamura-Pereira, M., Saucedo, M., Bouvier-Colle, M.-H., & Leal, M. (2016). Caesarean delivery and postpartum maternal mortality: A population-based case control study in Brazil. PLoS ONE, 11(4), e0153396. https://doi.org/10.1371/journal.pone.0153396
Fahmy, W. M., Crispim, C. A., & Cliffe, S. (2018). Association between maternal death and cesarean section in Latin America: A systematic literature review. Midwifery, 59, 88-93. https://doi.org/10.1016/j.midw.2018.01.009
Garcia-Mejido, J. A., Gutierrez, L., Fernandez-Palacín, A., Aquise, A., & Sainz, J. A. (2017). Levator ani muscle injuries associated with vaginal vacuum assisted delivery determined by 3/4D transperineal ultrasound. Journal of Maternal-Fetal and Neonatal Medicine, 30(16), 1891-1896. https://doi.org/10.1080/14767058.2016.1228104
Hammad, I. A., Chauhan, S. P., Magann, E. F., & Abuhamad, A. Z. (2013). Peripartum complications with cesarean delivery: a review of Maternal-Fetal Medicine Units Network publications. The Journal of Maternal-Fetal & Neonatal Medicine, 27(5), 463-474. https://doi.org/10.3109/14767058.2013.818970
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
Keag, O. E., Norman, J. E., & Stock, S. J. (2018). Long-term risks and benefits associated with cesarean delivery for mother, baby, and subsequent pregnancies: Systematic review and meta-analysis. PLoS Medicine, 15(1), e1002494-1002422. https://doi.org/10.1371/journal.pmed.1002494
Kearney, R., Fitzpatrick, M., Brennan, S., Behan, M., Miller, J., Keane, D., O’Herlihy, C., & DeLancey, J. O. L. (2010). Levator ani injury in primiparous women with forceps delivery for fetal distress, forceps for second stage arrest, and spontaneous delivery. International Journal of Gynecology and Obstetrics, 111(1), 19-22. https://doi.org/10.1016/j.ijgo.2010.05.019
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
Mascarello, K. C., Horta, B. L., & Silveira, M. F. (2017). Maternal complications and cesarean section without indication: systematic review and meta-analysis. Revista de saude publica, 51, 105. https://doi.org/10.11606/S1518-8787.2017051000389
McDonald, E., Gartland, D., Small, R., Brown, S. (2015). Dyspareunia and childbirth: a prospective cohort study. BJOG: An International Journal of Obstetrics and Gynaecology 122(5), 672 – 679. https://dx.doi.org/10.1111/1471-0528.13264
Nilsson, I., Åkervall, S., Milsom, I., & Gyhagen, M. (2016). Long-term effects of vacuum extraction on pelvic floor function: a cohort study in primipara. International Urogynecology Journal, 27(7), 1051-1056. https://doi.org/10.1007/s00192-015-2928-x
O’Neill, S., Kearney, P., Kenny, L., Khashan, A., Henriksen, T., Lutomski, J., Greene, R. (2013). Caesarean delivery and subsequent stillbirth or miscarriage: Systematic review and meta-analysis. PLoS ONE 8(1), e54588 – 14. https://dx.doi.org/10.1371/journal.pone.0054588
Shek, K. L., & Dietz, H. P. (2010). Intrapartum risk factors for levator trauma. BJOG: An International Journal of Obstetrics and Gynaecology, 117(12), 1485-1492. https://doi.org/10.1111/j.1471-0528.2010.02704.x
Volløyhaug, I., Mørkved, S., Salvesen, Ø., Salvesen, K. (2015). Forceps delivery is associated with increased risk of pelvic organ prolapse and muscle trauma: a cross-sectional study 16-24 years after first delivery. Ultrasound in obstetrics & gynecology, 46(4), 487 – 495. https://dx.doi.org/10.1002/uog.14891
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
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Tags: caesarean section, harm, infertility, instrumental birth, maternal mortality, miscarriage, pelvic floor trauma, placenta praevia, prolapse, risk, Stillbirth, uterine rupture
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Birth Small Talk 
Thanks Kirsten- the increased use of CTG’s is a real bug bear of mine at the moment but add in the fact that we now have central CTG monitoring at SCUH as well has made it even worse. Is there much research out there on the impact of central monitoring on both midwives and women?
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Only mine (working on getting publications out…) and this one – Brown, J., McIntyre, A., Gasparotto, R., & McGee, T. M. (2016, May 31). Birth outcomes, intervention frequency, and the disappearing midwife-potential hazards of central fetal monitoring: a single center review. Birth, 43(2), 100-107. https://doi.org/10.1111/birt.12222
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Kirsten, thank you so much for sharing such important information, very much appreciated.
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Very useful thanks. You discuss risks of instrumental birth, but I can’t see here reference to an increased chance of instrumental birth with use of CTG.
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Thanks Kathryn, I’m glad you found it useful. The Alfirevic et al 2017 Cochrane review found higher rates of instrumental birth with CTG use. This was also seen in the large population study of low risk women done by Heelan-Fancher in 2019, and in the meta-analysis by Al Wattar in 2021.
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