A few reasons to be cautious about the idea of routinely scanning for breech presentation near term

This week saw the publication of a study claiming that “universal late pregnancy ultrasound in nulliparous women (1) would virtually eliminate undiagnosed breech presentation, (2) would be expected to reduce foetal mortality in breech presentation, and (3) would be cost effective if foetal presentation could be assessed for less than £19.80 per woman.” (Wastlund et al 2019).

In, ‘Screening for breech presentation using universal late-pregnancy ultrasonography: A prospective cohort study and cost effectiveness analysis’, Wastlund et al (2019) “sought to determine the cost effectiveness of universal ultrasound scanning for breech presentation near term (36 weeks of gestational age [wkGA]) in nulliparous women.”

Some people have begun to express concern about the implications of this paper and the fact that it hasn’t considered the fact that breech birth is seen by many as a variation of normal. Neither has it explored the wider picture of women’s decision making. Here are a few of the issues that have not been taken into account within the study and/or in some of the media reporting of the research.


Further increasing the caesarean rate

The claim that routine scanning would ‘prevent 4000 emergency caesareans per year’ has been seen by some as misleading, because if the ‘answer’ to finding a baby in a breech presentation is to offer a caesarean section as one of the options, then the overall number of caesareans may well increase.

It may be true that an elective (planned) caesarean is preferable to an emergency caesarean but women also need to know that, if late-pregnancy scanning is offered and they decide to have it, their chance of being offered a caesarean may go up. This is of particular concern given the already rising caesarean section rate, which sits amidst the rise in other interventions but without good evidence of improvements in outcomes. Other interventions that would be offered to women found to have breech-presenting babies, such as external cephalic version, also have potential downsides as well as potential benefits.


It’s not a guarantee

We need to understand that scanning every woman at 36 weeks of pregnancy isn’t a guarantee that all breech births will be prevented. Even though most babies don’t turn after this time, some will, and some babies who are breech at 36 weeks of pregnancy will turn the other way up spontaneously.

Just yesterday, a friend of a friend had a caesarean for a baby who had been breech on a scan and who was head-down when the caesarean was done. This isn’t a rare event; it happens more often than you might think. We need to understand that there is no such thing as a guarantee, or a risk-free option.


Is it safe?

Ultrasound remains a relatively unevaluated technology, and campaigners are still calling for research into the safety of ultrasound, especially in response to data that has emerged from Chinese research on this intervention.

Scanning is currently in use where a problem is suspected, and will often be offered on an individual basis if there is uncertainty about the baby’s position. In this scenario, the potential benefits are deemed to outweigh the potential risks. It is the suggestion that all babies should be exposed to another scan that is controversial.


What are the wider costs?

Although the study authors spoke about the financial costs of ultrasound scanning, this research did not consider the wider costs to women, which include (but are not limited to) the physical, emotional, social and other costs of this screening.

We know that screening leads to anxiety for many women and we also know that all screening will lead to some women being told that they have a problem (and thus being offered intervention) when they do not.

It is vital that these costs and the way that this might affect individuals are considered and that decisions aren’t made on the basis of financial considerations alone.


A variation of normal?

The study assumes that vaginal breech birth is a hazardous, unwanted outcome. This is a controversial statement that not everyone would agree with. As above, breech birth is seen by many people as a variation of normal, and many women prefer to have their breech baby vaginally.

Routine scanning may put more unwanted pressure on more women. In relation to outcomes, we do know that medically-managed vaginal breech birth seems to lead to poorer outcomes than caesarean section, but those are not the only two options. Breech babies can also be born physiologically, without routine medical intervention or management (unless there is a problem and it is warranted).

We are seeing more and more research on how physiological breech birth can be safe, and a recent analysis even shows that “home or birth center setting [which would also involved an approach supportive of a woman’s physiology] leads to high rates of vaginal birth and good maternal outcomes for both breech and cephalic term singleton presentations”.

While many people would argue that hospital is the best location for breech birth, there are options for this type of birth that are not being taken into account in this analysis.


Wastlund D, Moraitis AA, Dacey A et al (2019). Screening for breech presentation using universal late-pregnancy ultrasonography: A prospective cohort study and cost effectiveness analysis. PLOS Medicine https://doi.org/10.1371/journal.pmed.1002778

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