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Does intrapartum CTG monitoring save lives?

Dr Kirsten Small is a project lead with the Transforming Maternity Care Collaborative. Yesterday she delivered the closing keynote address at the GOLD Obstetric Conference, speaking about why it is so difficult to align clinical practice with the research evidence. Kirsten hosts the Birth Small Talk blog and her post today reviews the research evidence she summarised in her address. She has kindly shared it here as well. 

If you are interested in pursuing research relating to the use of fetal heart rate monitoring in labour please connect with us via our contact form

 

Today’s post examines the research evidence about CTG monitoring with regards to stillbirth and neonatal death. This is a deep dive for my fellow data geeks who like to read the fine print, not the executive summary. The short version is – no. Using a CTG to monitor a woman in labour doesn’t prevent the death of her baby. If you are keen to know the details, read on!

Intrapartum CTG monitoring in low risk populations

This is the least controversial area of evidence, and the one most maternity clinicians are familiar with. Of the eleven randomised controlled trials that have compared CTG monitoring with intermittent auscultation (IA) during labour, three were done in low risk populations, five in high risk populations and the remaining three in mixed risk populations or where risk was not specified (Alfirevic et al., 2017).

The three low risk trials were Kelso et al., 1978, Leveno et al., 1986 and Wood et al., 1981. A total of 16,049 births were included in this analysis, which showed no statistically significant difference in the perinatal mortality rate (RR 0.87, 95% CI 0.29 – 2.58).

It has been almost 40 years since the last of these trials was performed. It could be argued that CTG technology has improved, or that we are better at CTG interpretation now. Heelan-Fancher et al. (2019) examined a large population data set from two states in the United States, specifically looking at birth outcomes for low risk women. This was not a randomised controlled trial – rather it was a non-experimental analysis of what happens in practice when women are monitored by CTG or by IA, with a very large sample size (1.5 million births). They didn’t report on intrapartum stillbirth. They found no significant difference in the neonatal mortality rate when CTG monitoring was used.

On the basis of available evidence, there is nothing that suggests that use of CTG monitoring rather than IA reduces the perinatal mortality rate in women considered to be at low risk. That’s not all that controversial. Most people in maternity care know this particular bit of information.

Intrapartum CTG monitoring in mixed, unknown, and high-risk populations

There is a widespread assumption that the absence of mortality benefit derived from CTG monitoring in labour ONLY applies to women considered to be low risk. We wouldn’t be using CTGs so widely if they didn’t save lives, right? But what does the evidence actually say regarding the use of intrapartum CTG monitoring in women who are not at low risk?

The randomised controlled trial evidence regarding high risk populations consists of five studies published over 6 papers, over a thirty-year period, starting in 1976 and continuing to 2006 (Haverkamp et al., 1979; Haverkamp et al., 1976; Luthy et al., 1987; Madaan and Trivedi, 2006; Renou et al., 1976; Shy et al., 1987). In addition, there are four studies published over five papers which were conducted in populations with both women considered to be at lower and higher risk or where the risk profile of the population was not described (Grant et al., 1989; Kelso et al., 1978; MacDonald et al., 1985; Neldam et al., 1986; Vintzileos et al., 1993). With my co-authors Associate Professor Mary Sidebotham, Professor Jenny Gamble, and Professor Jennifer Fenwick, we have synthesised the findings from these populations (Small et al., 2020).

In the high-risk population (n = 1,975), perinatal mortality was not significantly different when CTG was compared with IA (RR 1.17, 95% CI 0.62 – 2.22). There was also no statistically significant difference in mortality in the mixed-risk population (n = 15,994, RR 0.67, 95% CI 0.36 – 1.23). The mortality rate was higher in the mixed risk population than it was for the low risk population, and higher again for the high-risk population, indicating that researchers have correctly identified populations of women with higher risk.

Note that the number of women in the high-risk population is small. It has been argued that with a larger sample size a difference would be detected but that it would be unethical to recruit women considered to be a high-risk to further RCTs because the non-experimental evidence supporting the use of intrapartum CTG monitoring is so compelling. We set out to examine this assertion and examined the nonexperimental evidence (Small et al., 2020).

Non-experimental research

Our searches located 27 papers published between 1972 and 2018 which provided evidence about the use of intrapartum CTG monitoring in high-risk populations. We then used a tool (ROBINS-I) to assess the degree to which the findings of the research might be affected by bias – that is that the findings were due to something other than CTG use. 22 papers were at critical risk of bias and another was a serious risk. Most of these papers compared a time period prior to the introduction of CTG monitoring with a period after it was introduced, without controlling for any of the other changes to practice which might improve outcomes over time. Given the high risk of bias, the findings from these papers should not be relied on to guide practice as a consequence. The remaining five studies were assessed to be at moderate risk of bias. According to the ROBINS-I tool, studies at moderate risk of bias can be relied upon to inform clinical practice.

Starting with the studies at critical or serious risk of bias, only five of these studies showed a statistically significant reduction in perinatal mortality out of fourteen where this could be calculated. In the studies at moderate risk of bias (which ranged in size from 235 to 1.2 million women), no significant differences in perinatal mortality rates were reported. The argument that the non-experimental evidence presents a compelling argument for intrapartum CTG monitoring can’t be sustained on the basis of the available evidence.

Where to next?

Where does that leave us as clinicians and what recommendations can we make on the basis of these findings? We have an ethical obligation to include information regarding the lack of effectiveness of CTG monitoring in our discussions about intrapartum fetal monitoring with birthing women, regardless of their risk profile (Sartwelle et al., 2020) and to support their informed decision making. However, doing currently places clinicians at odds with professional guidelines. Professional guidelines are meant to be evidence informed, yet this is clearly not the case for intrapartum fetal monitoring. In order to support clinicians to provide evidence-informed care, there needs to be stronger recognition in professional guidelines that the evidence in favour of intrapartum CTG monitoring is far from compelling and that using IA instead is not proof of unprofessional practice.

The full reference list is available on the post on Birth Small Talk. 

 

Overcoming barriers to obstetric support for midwifery continuity of care models

by Midwives Siubhan McCaffery and Professor Jenny Gamble, with Obstetrician Kirsten Small

One of the frequently mentioned barriers to the expansion of midwifery continuity of care models is a lack of support from obstetricians. There is a small body of research that sheds some light on this lack of support. These studies have shown that the issues include differing birth-related philosophies between maternity care providers, medical dominance of the maternity-care landscape, medical officers’ misunderstanding of what midwifery is, and the impact of maternity reform on medical maternity care providers.

One study reported on a cohesive and accepting culture across midwifery and obstetrics which was created through strong knowledge of the model and acceptance of the associated evidence relating to midwifery continuity of care (Styles, et al., 2020). While this was the exception, rather than the norm, it does show that it is possible to overcome the challenges and generate multi-professional teams that support midwifery continuity of carer models.

We have both worked in a variety of maternity care settings and have our own first-hand experience of setting up and working in midwifery continuity of care models. It is our belief that many of the concerns of obstetricians can be addressed through education or through exposure to well-functioning models of care. Here we explore and address three common concerns.

Concern #1 Uncertainty about professional roles

Historically, obstetricians have by default been considered as the leader of any maternity care team. When midwives move into the role of primary care provider, this necessitates a shift in role for the obstetrician as well. This can cause discomfort simply because it is unfamiliar but provides a valuable opportunity for obstetricians to reflect on what they want to contribute to maternity care and how they would like to structure their role.

The obstetricians’ role shifts from being primarily about supporting the birthing woman, and the midwife supporting the obstetrician to do that; to the obstetrician supporting the midwife as they support the birthing woman. The primary relationship the obstetrician has in a midwifery continuity of care model is with the midwives, rather than birthing women. The concept of measuring good obstetric practice changes from being chiefly about whether the woman was happy with the obstetrician’s care (though that remains important), to being about whether the midwife was happy with the support provided by the obstetrician.

As obstetricians shift into this new role, there is also an opportunity to negotiate with midwives who will make up the team about how members of each profession work with one another. We take for granted that we understand our own and each other’s roles, yet this is often not accurate. Rather than representing a threat to obstetric practice, role clarity for both professions can reduce workload and anxiety, and improve the safety of practice.

Concern #2 Uncertainty about professional responsibility

Tied to the concept of the obstetrician as the leader, is the sense that obstetricians are ultimately responsible for the actions of every member of the healthcare team in producing good outcomes. There is no basis for this assumption in law, which is clear that clinicians are responsible for their own actions and not that of others. Along with providing an opportunity to renegotiate roles, shifting to midwifery continuity models of care provides a chance to be clear about lines of responsibility.

The most effective way for obstetricians to be clear about their risk exposure is to not take on care responsibilities for women until a midwife escalates care to them. This is easy to achieve in a midwifery continuity of care model where the only time an obstetrician becomes involved in woman’s care is when they are asked to do so by a midwife who has the woman’s agreement. Hybrid models, where obstetricians review healthy women at some point, make the lines of responsibility fuzzy and don’t improve outcomes. They should therefore not be used.

Concern #3 Lack of forewarning

While the suggestion that obstetricians don’t take on care for women until requested reduces workload and medicolegal risk, this can generate concern that they will need to step into a care role without forewarning. Many obstetricians feel more comfortable when they have had the opportunity to meet and assess women during the antenatal period, on the assumption that they might be able to prevent complications from arising during or after birth.

Evidence shows that the outcomes of midwifery continuity of care are at least as good as they are for obstetric led care (Sandall et al., 2016). This is only possible because midwives are at least as good as obstetricians at risk assessment and management. The circumstances under which midwives request the input of obstetricians are clearly set out, ensuring that obstetric involvement is achieved before a clinical situation has evolved into a major complication, when this is possible to do so.

It is important to acknowledge, that even with significant levels of obstetric input in an obstetric led model of care that unexpected emergencies still arise. It is therefore a myth that having a check-up with an obstetrician can avoid these. Being able to respond to an emergency situation without being forewarned will always be a feature of the work required of obstetricians, regardless of the model of care. This should not be used as a reason to limit access to midwifery continuity of care models.

In closing

As a midwife and an obstetrician, we have both experienced the benefits of working in midwifery continuity of care models. Not only are the clinical outcomes excellent, but the restructuring of working relationships between midwives and obstetricians that occur with the shift in model enhance professional relationships and help to make our professional lives more meaningful. There is joy and reward to be found in working in multi-professional teams with clear understanding and respect for each other’s roles and responsibilities.

 

Sandall, J., Soltani, H., Gates, S., Shennan, A., & Devane, D. (2016.) Midwife-led continuity models versus other models of care for childbearing women. Cochrane Database of Systematic Reviews, 4(11), CD004667.

Styles, C., Kearney,L., & George, K. (2020). Implementation and upscaling of midwifery continuity of care: The experience of midwives and obstetricians. Women and Birth, in press.