Invisible harms of CTG use

Bleeding after birth continues to be a significant cause of poor health and death for women. This is particularly the case in low-income countries where anaemia is more common due to nutritional challenges and parasitic infections. The WOMAN-2 trial has been investigating whether tranexamic acid (a medicine that supports rapid blood clotting) can improve outcomes. The study team recently published a paper where they looked at the impact that episiotomy has on blood loss at birth (WOMAN-2, 2026).

I’m going to summarise their findings first – and then link this to one of the holes we have in research about CTG use.

What did they do?

Women from hospitals in Nigeria, Pakistan, Tanzania, and Zambia were asked to take part in the study if they were anaemic (haemoglobin of under 99 g/L). In this side part of the larger study, they measured the number of women who had a postpartum haemorrhage (more than 500 mL blood loss was estimated, or there were other physiological signs of heavy bleeding like low blood pressure). They looked to see if there was a difference between women who had and did not have an episiotomy performed. All the women in this study had vaginal births, and 3% had assistance with forceps or vacuum devices. Induction of labour was used for 12% of the women.

What did they find?

In this study, 4,355 women had an episiotomy and 10,713 did not (29%). The average haemoglobin level before birth was 83 g/dL (moderately severe anaemia).

Clinically diagnosed postpartum haemorrhage was 8.3% in women who had an episiotomy and 6.3% in women who did not. After mathematical adjustment for other factors that might have impacted on the rate of bleeding, episiotomy was found to be associated with a higher rate of postpartum haemorrhage (OR 1.88 95% CI 1.33 – 2.66). Women who were more anaemic to start with were more likely to have a postpartum haemorrhage with an episiotomy than those with milder anaemia. The relationship between episiotomy and bleeding was the same whether it was the woman’s first birth or not.

The authors of this study estimated that shifting to a policy of restricted use of episiotomy would have prevented as many as 22% of the postpartum haemorrhage cases.

What does this have to do with CTG use?

There’s no information in this paper about the type of fetal heart rate monitoring used. I’m going to assume that continuous CTG was probably unlikely. What I do know for certain is that evidence from randomised controlled trials show that CTG use is associated with higher rates of forceps and vacuum assisted births than intermittent auscultation (Alfirevic et al., 2017). Here in Australia the WHA Perineal Protection Bundle recommends routine episiotomy for all first-time mothers having an instrument assisted birth, with this practice supported by RANZCOG (2020). The RCOG (2020) in the UK leans towards this direction as well, without actually making a strong recommendation.

In addition, abnormal fetal heart rate patterns in the late pushing stage are considered as a “medical indication” for episiotomy (Nassar et al., 2019). There is, by the way, absolutely no evidence to support this practice, and it doesn’t make a lot of sense physiologically either. While intermittent auscultation can also detect abnormal patterns, they are more likely to be recognised when CTG monitoring is in use, so you could reasonably expect a higher episiotomy rate.

So there are at least two good reasons to suspect that postpartum haemorrhage rates might be higher when continuous CTG monitoring is in use during the pushing stage of labour. Here’s the thing though – we don’t actually know. No one has looked at this question in research during the sixty years CTG monitoring has existed.

Researchers have had plenty of time to get to it. So why hasn’t it been done? First, because this is FETAL monitoring technology used in an obstetric culture that focusses on the fetus as the primary patient, outcomes affecting women were just not on researcher’s minds as they were designing studies.

Second, when you strongly believe that CTG monitoring is fantastic, why would you go out of your way to find out whether it might be harmful? It remains possible to apply the argument that “well, it can’t hurt, so let’s use the CTG”, simply because no one has made the effort to prove or disprove this position.

If there is then a rush for countries who previously did not have access to CTG use to introduce it as a “quality improvement” effort, my prediction is that more women will be needlessly harmed.

Decisions about fetal monitoring are for YOU to make. This is true whether you are considered “high risk” or not. It remains true even when someone tells you that you don’t have a choice and that CTG monitoring is mandatory. My recently published book Monitoring Your Baby In Labour: An Evidence-based Guide To Help You Plan Your Birth supports you to make these decisions.

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Details about where to buy it are here!

References

Alfirevic, Z., Devane, D., Gyte, G. M., & 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(2), CD006066. https://doi.org/10.1002/14651858.CD006066.pub3

Murphy DJ, Strachan BK, Bahl R, on behalf of the Royal College of Obstetricians Gynaecologists. (2020)
Assisted Vaginal Birth. British Journal of Obstetrics & Gynaecology, 127, e70–e112.

Nassar, A.H., Visser, G.H.A., Ayres-de-Campos, D., Rane, A., Gupta, S. and the FIGO Safe Motherhood and Newborn Health Committee. (2019). FIGO Statement: Restrictive use rather than routine use of episiotomy. International Journal of Gynecology & Obstetrics, 146: 17-19. DOI: 10.1002/ijgo.12843

RANZCOG. (2020). Instrumental vaginal birth. https://ranzcog.edu.au/wp-content/uploads/Instrumental-Vaginal-Birth.pdf

WOMAN-2 Trial Collaborators. (2026). Episiotomy and postpartum haemorrhage in women with moderate or severe anaemia: a cohort analysis of data from the WOMAN-2 trial. Lancet Global Health, 14(2), e224-e232. https://doi.org/10.1016/S2214-109X(25)00449-8