Stimulating conversation: does cold water wake babies in utero?

Thinking Outside the Box drinkStimulating conversation: does cold water wake babies in utero?

We may live in a time and culture in which research evidence is highly valued, but other kinds of knowledge can be just as useful in our lives and work.  Indeed, many of the questions relevant to women’s experiences and midwifery practice cannot be answered via formal research methods, and even when we have good-quality research findings, other issues still need to be considered.  For this and many other reasons, I have long taken the position that we need to value, explore and use other ways of thinking and knowing, and in this article I want to do just that by exploring a practice that is often used but seldom researched.


The cold drink theory

I noticed that the Royal College of Obstetricians and Gynaecologists (RCOG) librarians had considered a question posed to them about whether there was any evidence for the practice of giving a pregnant woman a drink of cold water to encourage fetal movement or improve reactivity in cardiotocography (RCOG 2015).  This practice is used in situations where a baby isn’t currently active and the woman and/or health professional would like it to be, for example where a woman is undergoing routine monitoring and the tracing of the fetal heart rate indicates that her baby is well but sleeping.  In this situation midwives may offer the woman something to drink in the hope of shortening the time that she has to remain on the monitor.  I think it is important to note, however, that this is not something that would be used if there was concern that there might be a problem.

The RCOG (2015) found no evidence to support this practice.  But a lack of research evidence doesn’t necessarily mean something doesn’t work, and I decided to ask midwifery and medical colleagues about their experience of this. I posed this question on social media and amongst colleagues, and I am going to share some of the responses in this and next month’s article, because they provide interesting food for thought about this topic and the knowledge we use in practice.


A range of responses

The respondents include midwives, student midwives, doctors and childbirth educators. I want to acknowledge that I have not used any of the usual means of ensuring that an investigation is sound, reliable and/or that the participants are representative of any particular group, so we should not over-estimate what we can take from this data.  One interesting element of using social media to gather data is that it is easy to see when others agree with (or ‘like’) a particular comment.  I don’t think it is unreasonable to suggest that a viewpoint which was ‘liked’ by many people is worth drawing attention to.  At the time of writing, the most popular comment was this one:

‘Working in antenatal Day Unit, [I] saw this work often and very quickly on a daily basis. Cold water and a biscuit normally made a huge difference in a CTG trace. The difference in a CTG could be framed to visualise to pregnant Mums the importance of regular meals. Too many Mums skip meals or fast despite evidence that it can affect their baby too. When cold water and a biscuit didn’t work, it rang alarm bells and reason to look more closely.’ Midwife A

While other people raised some interesting points about which element of this trick is key to its success (which I will discuss next month), the above comment summarises the majority viewpoint.   Most respondents have seen some combination of food and/or fluid work well and often in this situation.  A few people questioned whether it was coincidental, or the placebo effect, and some noted that individual experience isn’t always reliable.  Several also expressed the belief that it is not always necessary to have research evidence in order to offer a low-tech option that is thought to be effective in solving a problem in the real world.


The importance of context

The vast majority of participants didn’t see a problem with the notion of using such a trick to wake a sleepy baby if the circumstances were appropriate, and some very experienced midwives and doctors reported having used this for many years with good results, but a couple of people questioned whether a healthy baby should need to be stimulated in order to persuade it to move.  They felt that this practice may be inappropriate, but their response seemed to be limited to one particular context (for instance advising a woman on the phone who called a hospital to report reduced fetal movements), and so we don’t know whether their view would be the same if the circumstances were different.

As with so many other areas of practice, there is a continuum of ideology and some practitioners begin from the premise that all is probably well until evidence of a problem is found, while others take a more cautious approach and have a lower threshold for seeking technological proof of health and wellbeing.  Several people shared their concern that the approach taken within the modern maternity services is increasingly unbalanced.  That is, there is a tendency to prioritise finding the occasional unwell baby at the cost of exposing larger numbers of healthy women and babies to further screening and/or intervention.  A couple of respondents referred to a worst case scenario (e.g. the woman going on to have an emergency caesarean section, which may lead to criticism of the midwife who gave her food and fluid) as a baseline for decision-making, although the majority focused more on the most likely outcome (that all was well and the baby was sleeping) and were concerned about the potential downsides of focusing on the worst possible outcome.

Many respondents either openly or tacitly acknowledged the importance of taking into account the wider context of the woman and baby when deciding whether it was safe to suggest this practice or a different course of action.  Midwives wrote about taking into account factors such as the location of the woman (who may be in hospital or at home in a rural community) and her health history, social and emotional situation.  My overall sense was that the majority of respondents were open to using this in certain situations and within a framework of providing individualised care amidst the application of common sense.

They had even more to say about whether and how it worked, though.


Fluid, coldness or sugar?

Soon after the first discussion of this question began on social media, respondents started to offer and debate a range of theories about the different elements of exactly what substance(s) were being offered to women. Although the initial question referred to cold water – and, indeed, many midwives reported cold or iced water being used in practice – there was some debate about whether the water temperature mattered.  Several practitioners suggested that any positive benefit came from the fluid alone or from the addition of sugar, and in some areas cordial or fruit juice is offered instead of water. Some also offered sugar in the form of food, as I will discuss below.

There was very little consensus on which element(s) of this made a difference.  Some people seemed convinced that coldness was paramount, while others expressed the view that the temperature of the drink doesn’t matter at all.  In what one midwife described as ‘the wilted pot plant theory’, the coldness and sugariness of the fluid are deemed irrelevant.  Yet others viewed the water principally as a vehicle for sugar, which caused a few people to share their concern that sugar was something to be actively avoided.


Food, noise and physiological speculation

These debates extended beyond water, with some of the proponents of the sugar-based theories recommending biscuits, nuts or chocolate instead of or as well as a drink.  Another couple of people speculated that the ‘gulping, swallowing, churning and digestion’ noise of the water being drunk by the woman may stimulate or wake the baby, while someone else shared a story of seeing a baby’s heart rate respond to a change in the music playing in the background.  This was followed by the suggestion of placing the speaker in a TV handset on the woman’s abdomen as a modified version of vibratory acoustic stimulation (VAS), which has been shown to be useful in altering periods of low reactivity observed when normal fetuses are being monitored (Ohel et al 1986).  VAS was recommended as being particularly useful if the woman was fasting in preparation for possible caesarean section.  This observation again demonstrates the centrality of context in the responses, with practitioners explicitly noting that this kind of practice was useful in situations where women needed reassurance or wanted routine monitoring to end, but not something they would suggest if they or the woman were concerned about the baby’s wellbeing.

I have long noted that birth practitioners often engage in physiological speculation and many of these respondents did just that.  However, there was little consensus in this area: for almost every speculation put forward to explain why one element was relevant, there was a counter-speculation which in turn generated a different or amended theory.  Some practitioners feel that the water needs to be cold, while others said they couldn’t see how this would make a difference because coldness wouldn’t be felt by the baby.  Other theories included the possibility that cold water may be absorbed more quickly than hot, that it may raise fluid levels and/or blood pressure, trigger an adrenalin surge, influence the release of hormones and/or neurotransmitters that may wake the baby, or that the placebo effect is in play.  There is, of course, no law that says it can only be one of these things, but we also, of course, cannot be certain that it is any of them!

If nothing else, the range of arguments that emerged supports the notion that biological plausibility can be claimed for almost any element of a theory; a topic often discussed by those promoting evidence-based practice. This is one reason why it is deemed vital that we carry out studies to determine which factor is the key in such situations, but I think it is important to remember that such studies can’t always tell us why something works and that there is still value in debating theories.


Now what?

There exist a number of different possibilities as to where this kind of exercise can lead us.  For some, the exploration of other ideas is the inductive yin to the deductive yang of quantitative research.  In other words, exploratory conversations such as the one I’ve described in this article are seen principally as ways of generating knowledge about possibilities which can then be tested more formally in quantitative research.  I don’t have a problem with the notion of testing hypotheses in this way, but I would have to say that I am more open to valuing other ways of knowing and alternative forms of knowledge in and of themselves and seeing the conversations themselves as having potential value, with the caveat that I think discernment, reflection and open-mindedness are vital components of such an approach.

I would claim that this exercise has raised some interesting issues and avenues for reflection and further investigation which would probably never emerge from a quantitative research study evaluating this single intervention.  The concept that arose again and again was the importance of the woman’s individual context: the one thing that gets lost when we rely solely on the results of randomised controlled trials for knowledge about interventions and practices.  For this reason alone I am going to conclude by arguing that we need to keep talking about our thoughts and experiences just as much as we need to consider the findings of good-quality research.

Acknowledgement: Thanks to all the practitioners who discussed this with me on social media, on email or in person.



Ohel G, Birkenfeld A, Rabinowitz R et al (1986).  Fetal response to vibratory acoustic stimulation in periods of low heart rate reactivity and low activity.  AJOG 154(3): 619–21.

RCOG (2015). Cold water and fetal heart and movements.

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