Birth Small Talk

Talking about birth

Why does heightened awareness of reduced fetal movements not prevent perinatal death?

Photo by Matt Walsh on Unsplash

A recent metanalysis has brought together all randomised controlled trials, and two non-randomised studies, about fetal movement monitoring (Hayes, et al., 2023). As well as the many small trials, they included the three large and recent trials – Mindfetalness (Akelsson et al, 2020), My Baby’s Movements (Flenady, et al., 2022), and the AFFIRM trial (Norman, et al., 2020).

Their review was good quality. They identified the risk of bias for each of the studies and separated the trials according to the specific focus of each, like this –

  • Two trials used an intervention encouraging women to note movement patterns and compared this to standard care.Eight asked women to count movements and compared this to standard care.
  • One trial compared fetal movement counting with assessment of estriol and human placental lactogen in the third trimester.
  • One trial compared universal ultrasound screening for women presenting with reduced fetal movement with a more restricted set of indications for ultrasound screening.
  • Two trials compared universal ultrasound screening plus human placental lactogen measurement with standard care.
  • The final trial (AFFIRM) combined both awareness of fetal movement with standardised management and compared this with standard care.

Let’s look at the outcomes

Stillbirth

  • Awareness – no statistical difference in stillbirth rates. The adjusted odds ratio was 1.19 (95% confidence intervals 0.96 – 1.47).
  • Counting – stillbirth rates were also not statistically significantly different in this group of studies either (adjusted odds ratio of 0.69, 95% confidence intervals of 0.18 – 2.65).
  • Counting vs blood testing – stillbirth rates were not statistically significantly different to blood testing (adjusted odds ratio 3.67, 95% confidence intervals 0.15 – 90.17).
  • Universal ultrasound assessment – again, there was no statistically significant difference in stillbirth rates (adjusted odds ratio 0.53, 95% confidence intervals 0.05 – 5.86).
  • Universal ultrasound assessment plus blood testing – no stillbirth data
  • Awareness plus standardised management – no statistically significant difference in stillbirth (adjusted odds ratio 0.86, 95% confidence intervals 0.7 – 1.05).

The authors provided a table in their supplementary data listing the number of stillbirths in each arm of each trial. [While I have added these together for you, some caution needs to be applied to interpreting these results. The trials used different interventions and were conducted in different populations. The definitions of stillbirth were not standard across all trials.] The stillbirth rate was 29 per 10,000 births in the intervention arms of the studies and 29 per 10,000 births in the control groups. The total number of births included in the review was 809,636 (minus one trial that did not provide their population size).

Neonatal death

The picture was similar here. Only the awareness studies and the AFFIRM trial provided data for this outcome and neither approach was associated with a lower rate of neonatal death in the treatment arm of the trials. Adding stillbirth and neonatal death together to get the perinatal death rate also showed no difference between the intervention arm and standard practice.

Impact on labour onset and mode of birth

  • Studies where the intervention was promotion of awareness of movement patterns showed a close to statistically significant (but not quite), and small in size, reduction in the use of induction of labour (odds ratio 0.98, 95% confidence intervals 0.96 – 1.0). This was also the case for the use of caesarean section (odds ratio 0.98, 95% confidence intervals 0.95 – 1.0).
  • Fetal movement counting did not impact the caesarean section rate compared to standard care and no data were given for induction of labour.
  • Compared to hormone analysis, fetal movement counting had no impact on the caesarean section rate. No data were given for induction of labour.
  • Neither of the two studies comparing ultrasound screening plus blood tests against standard care showed a difference in caesarean section rates. One showed no difference in the induction of labour rate and the other a large and statistically significant increase (odds ratio 2.87, 95% confidence intervals 1.32 – 6.22).
  • Caesarean section rates both for any reason (adjusted odds ratio 1.15) and “emergency” caesarean section (odds ratio 1.09) were significantly higher in the intervention arm of the AFFIRM trial. The induction of labour rate was lower in the intervention arm (adjusted odds ratio 0.81, 95% confidence intervals 0.78 – 0.84).

Other outcomes of note

  • Studies where the intervention was promotion of awareness of movement patterns showed a statistically significant but small in size reduction in the rate of admission to the neonatal nursery (odds ratio 0.9, 95% confidence intervals 0.87 – 0.94). A lower rate of Apgar scores below seven at five minutes (odds ratio 0.94, 95% confidence intervals 0.9 – 1.0) seen. This came close to, but didn’t quite reach, statistical significance. Preterm birth rates were slightly higher in the intervention group but also didn’t quite reach statistical significance (odds ratio 1.03, 95% confidence intervals 0.99 – 1.08).
  • Fetal movement counting yielded no change in the rate of neonatal nursery admission or the preterm birth rate.
  • Ultrasound assessment plus blood testing did not alter the rate of neonatal nursery admissions compared with standard care.
  • The AFFIRM trial (movement awareness plus standardised management) was associated with statistically significant increases in low Apgar scores in the intervention arm (odds ratio 1.12, 95% confidence intervals 1.07 – 1.18), and no difference in the rate of preterm birth. Neonatal nursery admission rates were higher in the intervention group, and this approached but did not reach statistical significance (adjusted odds ratio 1.05, 95% confidence intervals 1.0 – 1.1).

In summary

There is no strong evidence to suggest that any, or all, approaches to promoting fetal movement monitoring and managing women who report altered or reduced movement patterns reduces fetal or neonatal death. Findings about other neonatal outcomes were variable with some being improved and others worse in the intervention arm. None of the trials extended followup to examine long term outcomes. Findings about the use of caesarean section and induction of labour varied, with no clear pattern of higher or lower rates of use in the intervention arms of the trials.

Why doesn’t it work?

Why is it that collectively the studies on interventions focussed on changes in fetal movements have not produced the outcomes expected? The logic behind the approach seems sound so it is reasonable to think it SHOULD work. One possibility is the curse of small numbers. When the outcome of interest is relatively rare, you need very large data sets to produce statistically significant differences even when these do exist. But I don’t think that’s what is happening here. The absolute rates of stillbirth were identical in both the intervention and control arms of the trials. So what else might be the problem?

I think the issue is that we take for granted the interventions that happen next. We should be looking more closely at whether these are useful or not. When a woman presents with reduced or changed fetal movements the usual management involves antenatal CTG monitoring, ultrasound assessment, and for some, the offer of induction of labour (or less often prelabour caesarean section). For fetal movement monitoring to prevent poor outcomes, one or a combination of these interventions need to prevent poor outcomes.

What do we do first – antenatal CTG monitoring

There has never been a randomised controlled trial, or any other type of research, comparing antenatal CTG monitoring with intermittent auscultation specifically for women presenting with concerns about fetal movement patterns. Four randomised controlled trials, with 1,627 women, have been conducted to address the question of whether antenatal CTG monitoring (compared to standard care with intermittent auscultation) improves perinatal outcomes. The trials were conducted between 1982 and 1985 and therefore the context of care has shifted significantly from today. None of these trials included women who presented with reduced fetal movements.

The findings from these trials were analysed in the 2015 Cochrane review by Grivell et al. The perinatal mortality rate for infants whose mothers were randomised to CTG monitoring was 23 per 1000. This was double the rate for infants born to women randomised to standard care, at 11 per 1000. The relative risk was 2.05 and it just failed to reach statistical significance with 95% confidence intervals of 0.95 – 4.42. That is, women who had CTG monitoring were a touch more than twice as likely to have their baby die, but this could be a chance finding due to the small number of women in the trials.

The only CTG monitoring trial where women presenting with altered fetal movement patterns were included was the 1999 trial conducted in the USA by Bracero et al. This trial enrolled 410 women, of whom 44 had reduced fetal movements. Computerised CTG interpretation using the Dawes-Redman criteria was compared with standard CTG interpretation. No differences in any measured perinatal outcome were found.

Antenatal CTG monitoring is considered standard care for women presenting with altered fetal movements. The confidence policy writers have in this recommendation has no substance. There is NO research supporting this as a beneficial intervention. Research about antenatal CTG monitoring for other indications is now 40 years old and suggested that CTG use was associated with worse perinatal mortality rates. Asking women to present to professional care for CTG monitoring when they experience altered fetal movement patterns is a profound example of the unscientific optimism that CTGs make things better.

What we do next – ultrasound scanning

The other common approach to care when women present with reduced fetal movements is to recommend an ultrasound scan. Here in Australia, guidelines (such as Daly, et al., 2018) recommend that ultrasound be considered for all women presenting with reduced fetal movements. Before launching into a critique of the literature I feel the need to start with a disclaimer that the evidence relating to fetal ultrasound assessment isn’t my area of expertise. I have spent years getting across the CTG evidence, but for ultrasound it’s more like hours over the past few weeks, along with clinical exposure to ultrasound during my years in clinical practice. I’m not promising I have found all the relevant literature relating to this topic. But I have done my best. If you have expertise in this area and want to contribute, send me an email!

There’s never been a randomised controlled trial comparing ultrasound assessment with no ultrasound assessment specifically for women presenting with reduced fetal movements. A Cochrane review (Alfirevic, et al., 2017) has examined the question of whether Doppler assessment improves outcomes for women at high risk, and some of the women included in some of the trials were enrolled due to reduced fetal movements. They found a small but statistically significant reduction in perinatal mortality from 1.7 to 1.2%, and lower rates of labour induction and caesarean section with Doppler ultrasound use. No long term follow-up has been conducted to examine how these babies do beyond the first weeks of life.

Hayes and colleagues cite evidence from Awad et al., 2018 and from the AFFIRM trial, both of which included ultrasound assessment in their research. Awad and colleagues collected retrospective data from two Canadian hospitals, each with a different approach to the management of women presenting with reduced fetal movemements. One referred all women for a biophysical profile (an ultrasound assessment that includes liquor volume, fetal movement, fetal breathing, and fetal tone), while the other only used this when the CTG was abnormal or oligohydramnios or fetal growth restriction was suspected on clinical grounds. In hospital one, 217 of 281 women had a biophysical profile. One woman from this hospital, who had not been referred for a biophysical profile, experienced a term stillbirth within two weeks of her presentation with reduced movements. In hospital two, 18 of 298 women had a biophysical profile performed. One woman, again without a biophysical profile, experienced a stillbirth at 27 weeks of gestation within two weeks of her initial presentation. This research doesn’t provide firm evidence in support of ultrasound use.

The AFFIRM trial (Norman, et al., 2018) included ultrasound assessment of fetal biometry and liquor volume in the package of care for women presenting with reduced fetal movement. They also recommended that when available, Doppler assessment should be performed. They found no statistically significant reduction in stillbirth, occurring at a rate of 4.40 per 1000 births prior to the intervention, and 4.06 per 1000 birth after the intervention period. There was also no change in in the perinatal mortality rate. I looked for, but was unable to find information about the rate of ultrasound use in both periods or about the rate of use of Doppler ultrasound.

The AFFIRM trial included a cost effectiveness study (Camacho, et al., 2022). To avoid one stillbirth, assuming 75% of women presenting with reduce fetal movements had an ultrasound scan, the additional cost to the NHS when using the AFFIRM intervention would be £210,051. Universal implementation of the program in Great Britain alone was estimated to cost £61.9 million per year. The cost effectiveness assessment makes it clear that introducing widespread practice change is not cheap, and taxpayers no doubt would expect that their money should be invested in impactful programs. The AFFIRM program doesn’t seem like good return on investment to me.

Two studies in the Hayes et al. review looked at ultrasound plus blood tests compared with routine care. One of these was the feasibility study for the AFFIRM trial (the final intervention didn’t include blood testing) (Heazell, et al., 2013). This study doesn’t really help address our question, as 97% of the woman in the standard care group and all the women in the intervention group had ultrasound scanning. The other was also a feasibility study (Armstrong-Buisseret, et al., 2020) and again standard care included ultrasound scanning, so it it not possible to learn anything about the impact of ultrasound scanning on outcomes from this study.

Not included in the Hayes et al. review (because it wasn’t published at the time they wrote their paper), is new Australian research examining the usefulness of ultrasound in the setting of reduced fetal movements (Turner, et al., 2023). This was a retrospective cohort study. They compared outcomes for 1,466 women presenting with reduced fetal movements who had comprehensive ultrasound assessment (fetal biometry including estimated fetal weight, assessment of liquor volume, umbilical and middle cerebral artery pulsatility index, and cerebro-placental ratio) within 48 hours of presentation with 2,207 women having a third trimester ultrasound for another indication, and matched them by gestational age.

They found no difference in the stillbirth rate, affecting 1 per 1000 births in both cohorts. There were also no differences in neonatal mortality, birthweight, cord blood acidosis, low Apgar scores or admission to the nursery. Induction of labour was
more common in the reduced fetal movement cohort, with a slightly lower gestational age at birth as a consequence. There were no differences in the mode of birth. I find the higher rate of use of induction of labour interesting. This research team also found no difference in the rate of abnormal scan findings, occurring in 20% of cases (women with reduced movements) and 21% of controls. This suggests to me that scan findings for women with reduced fetal movements were not used to inform the timing of birth in the same way that the same scan findings were used for women with other indications for ultrasound scan monitoring.

One of the proposed advantages of using ultrasound to assess women presenting with reduced fetal movements is the ability to identify small for gestational age fetuses that have not been detected through other means. Of the 3% of women presenting with reduced fetal movement who were then identified as having a small for gestational age fetus on scan, 35% had already been identified prior to this presentation, 10% had a previous scan with an estimated fetal weight of greater than the 10th percentile, and the remainder had no previous scans. 48 women needed to be scanned to detect one small for gestational age fetus.

Turner et al. also examined neonatal outcomes for women who presented with reduced fetal movements but didn’t have a scan. They found no difference in neonatal outcomes compared to those who had a scan. This type of study design, and the relatively small sample size can’t completely exclude the possibility that ultrasound scanning can improve outcomes, but the evidence from this study, and the others discussed so far, do not present compelling evidence that outcomes for women with reduced fetal movements are superior when ultrasound is used.

There is a randomised controlled trial underway (Damhuis, et al., 2021) comparing the use of the cerebro-placental ratio (a calculated measure that uses the pulsatility index from both the umbilical artery and the middle cerebral artery) to inform decision making among women presenting with reduced fetal movements who have a normal CTG and a normally grown fetus. We’ll have to be patient to see what comes of this one.

And then we do this…

The next of the common interventions offered to women who present with reduced fetal movement is to shift birth to an earlier gestation through the use of labour induction (mostly) or pre-labour caesarean section (less often). That’s really not my area of expertise. The assumption is that if you get the baby out earlier, you avoid stillbirth happening later. The logic is simple, but deceptive. Compared to spontaneous labour, prostaglandin and / oxytocin increase the risk of intrapartum hypoxic damage, and can lead to death. My understanding of the research here is that it is also a bit of a mess, with no clear evidence that induction of labour improves outcomes for most of the indications it is used for. Sara Wickham has written extensively on the (relative lack of) evidence for labour induction for many indications, so I suggest accessing her two excellent books and her many other free resources if you want to read more.

In summary

It shouldn’t come as a surprise that focussing attention on fetal movements and encouraging women to seek professional care hasn’t been shown to improve outcomes when the interventions that commonly follow on from this – CTG monitoring and ultrasound – have themselves not been demonstrated to improve outcome for this group of women, and I suspect the same is true for labour induction. Despite the absence of good evidence to support widespread changes to our practice regarding the assessment and management of women with reduced fetal movements, packages of care that include such changes (like the Saving Babies Lives (UK) and Safer Babies (Australia) bundles) have been introduced. They seem set to stay embedded in practice, rather than be considered as temporary adjustments and an opportunity to gather knowledge about their effects.

In the face of concern for fetal wellbeing, it is of course completely understandable that pregnant women and their families, and those who care for them, want to do everything in their power to achieve the best possible outcome. My prediction is that this desire, tied to strong faith in technology, will continue to drive the use of interventions for women with reduced fetal movements. The research focus will now shift to whether modifying or adding new technologies will fix the problem (like the shift to assessing the role of the cerebro-placental ratio in this population – before we have even established whether any form of ultrasound assessment is beneficial).

Why am I confident that this will be the case? Because that’s the history of intrapartum fetal heart rate monitoring. Everyone desperately wanted it to work, and so it became routinised even as evidence showing it didn’t work was coming in. Rather than persisting with designing and delivering programs of research that would answer the question of whether CTG monitoring in labour was useful or not, and for whom, research instead turned to other technologies used alongside the CTG to see if they could fix things – ST analysis, computer analysis, central fetal monitoring and so on. And so far, none if it seems to work any better than intermittent auscultation.

We keep doing the same thing in maternity care – introducing something that seems like a good idea but not fully evaluating it and then building on it rather than rethinking it – over and over again. It’s time to have an important conversation about how we change practice in maternity care and how we generate knowledge about what we do. What we have been doing doesn’t make sense, drives up the cost of care, and quite probably generates long term harms that we simply aren’t even taking into consideration.

References

Akselsson A, Lindgren H, Georgsson S, et al. (2020). Mindfetalness to increase women’s awareness of fetal movements and pregnancy outcomes: a cluster-randomised controlled trial including 39 865 women. British Journal of Obstetrics & Gynaecology, 127, 829–37.

Alfirevic Z, Stampalija T, Dowswell T. (2017). Fetal and umbilical Doppler ultrasound in high‐risk pregnancies. Cochrane Database of Systematic Reviews, 6, CD007529. DOI: 10.1002/14651858.CD007529.pub4.

Armstrong-Buisseret, L., Godolphin, P. J., Bradshaw, L., Mitchell, E., Ratcliffe, S., Storey, C., & Heazell, A. E. P. (2020). Standard care informed by the result of a placental growth factor blood test versus standard care alone in women with reduced fetal movement at or after 36+0 weeks’ gestation: a pilot randomised controlled trial. Pilot and Feasibility Studies, 6(1), 23. DOI: 10.1186/s40814-020-0561-z

Awad, N. A., Jordan, T., Mundle, R., & Farine, D. (2018, Apr). Management and outcome of reduced fetal movements-is ultrasound necessary? Journal of Obstetrics & Gynaecology Canada, 40(4), 454-459. https://doi.org/10.1016/j.jogc.2017.08.007

Bracero, L. A., Morgan, S., & Byrne, D. W. (1999). Comparison of visual and computerized interpretation of nonstress test results in a randomized controlled trial. American Journal of Obstetrics & Gynecology, 181(5 Pt 1), 1254-1258. https://doi.org/10.1016/s0002-9378(99)70118-3

Camacho, E. M., Whyte, S., Stock, S. J., Weir, C. J., Norman, J. E., & Heazell, A. E. P. (2022, Mar 22). Awareness of fetal movements and care package to reduce fetal mortality (AFFIRM): a trial-based and model-based cost-effectiveness analysis from a stepped wedge, cluster-randomised trial. BMC Pregnancy Childbirth, 22(1), 235. https://doi.org/10.1186/s12884-022-04563-9

Daly, L. M., Gardner, G. E., Bowring, V., Burton, W., Chadha, Y., Ellwood, D. A., Frøen, J. F., Gordon, A., Heazell, A. E. P., Mahomed, K., McDonald, S. J., Norman, J. E., Oats, J. J. N., & Flenady, V. (2018). Care of pregnant women with decreased fetal movements: Update of a clinical practice guideline for Australia and New Zealand. Australian & New Zealand Journal of Obstetrics & Gynaecology, 377(1), 1319-1316. https://doi.org/10.1111/ajo.12762

Damhuis, S. E., Ganzevoort, W., Duijnhoven, R. G., Groen, H., Kumar, S., Heazell, A. E. P., Khalil, A., & Gordijn, S. J. (2021). The CErebro Placental RAtio as indicator for delivery following perception of reduced fetal movements, protocol for an international cluster randomised clinical trial; the CEPRA study. BMC Pregnancy Childbirth, 21(1), 285. https://doi.org/10.1186/s12884-021-03760-2

Flenady V, Gardener G, Ellwood D, et al. (2022). My baby’s movements: a stepped-wedge cluster-randomised controlled trial of a fetal movement awareness intervention to reduce stillbirths. British Journal of Obstetrics & Gynaecology, 129, 29–41. https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-019-2575-1

Grivell, R. M., Alfirevic, Z., Gyte, G. M. L., & Devane, D. (2015). Antenatal cardiotocography for fetal assessment. Cochrane Database of Systematic Reviews, 9(9), CD007863. https://doi.org/10.1002/14651858.CD007863.pub4

Hayes, D. J. L., Dumville, J. C., Walsh, T., Higgins, L. E., Fisher, M., Akselsson, A., Whitworth, M., & Heazell, A. E. P. (2023). Effect of encouraging awareness of reduced fetal movement and subsequent clinical management on pregnancy outcome: a systematic review and meta-analysis. American Journal of Obstetrics & Gynecology MFM, 5(3), 100821. https://doi.org/10.1016/j.ajogmf.2022.100821

Heazell, A. E., Bernatavicius, G., Roberts, S. A., Garrod, A., Whitworth, M. K., Johnstone, E. D., Gillham, J. C., & Lavender, T. (2013). A randomised controlled trial comparing standard or intensive management of reduced fetal movements after 36 weeks gestation–a feasibility study. BMC Pregnancy Childbirth, 13, 95. https://doi.org/10.1186/1471-2393-13-95 

Norman, J. E., Heazell, A. E. P., Rodriguez, A., Weir, C. J., Stock, S. J. E., Calderwood, C. J., Cunningham Burley, S., Froen, J. F., Geary, M., Breathnach, F., Hunter, A., McAuliffe, F. M., Higgins, M. F., Murdoch, E., Ross-Davie, M., Scott, J., Whyte, S., & for the Affirm investigators. (2018). Awareness of fetal movements and care package to reduce fetal mortality (AFFIRM): a stepped wedge, cluster-randomised trial. Lancet, 392(10158), 1629-1638. https://doi.org/10.1016/S0140-6736(18)31543-5

Turner, J. M., Cincotta, R., Chua, J., Gardener, G., Petersen, S., Thomas, J., Lee-Tannock, A., & Kumar, S. (2023). Decreased fetal movements – the utility of ultrasound to identify infants at risk and prevent stillbirth is poor. American Journal of Obstetrics & Gynecology MFM, 5(2), 100782. https://doi.org/10.1016/j.ajogmf.2022.100782

Categories: antenatal CTG, CTG, EFM, New research, Obstetrics, Perinatal mortality, Stillbirth

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1 reply

  1. I love your posts they so agree with my beliefs – and it is super rewarding to know of the lack of evidence of benefit of so many interventions. I trained in 1982 and have constantly wondered why no one has researched No fetal monitoring against any fetal monitoring, let alone CTGs, I am not tales to tell, its one of my colleagues but so far have failed to log out and relog in as me …Chris Warren

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