The logic behind fetal movement monitoring is deceptively simple. When people feel sick they don’t move as much. There is evidence the same is true for the fetus. Reduced fetal movements are a way to conserve oxygen and nutrients when they are in short supply. Communicating this to women in a way that encourages them to seek professional care means they can make use of additional assessments (like antenatal CTG monitoring and ultrasound) and be offered the option of earlier birth by induction of labour or in some cases pre-labour caesarean section. And doing this should mean that stillbirth is prevented and babies are born in better condition.
There are strong psychological reasons we want this to be true – whether you are a maternity professional or the pregnant woman or her family or someone close to her. Stillbirth is an awful outcome. Particularly close to term when, given the choice, there seems little to be gained from continuing the pregnancy in the face of additional risk. And there is evidence to support parts of the logic behind fetal movement monitoring. As a consequence, advice to undertake fetal movement monitoring is common and supported by guidelines in most high-income countries.
In recent years, more than one team of researchers have embarked on projects aimed at enhancing women’s self monitoring of fetal movement patterns, encouraging them to access professional help, and structuring the care provided when they do access that help. The AFFIRM and Mindfetalness trials are examples. Sometimes these projects are packaged along with other interventions, like the Safer Babies bundle here in Australia, or the saving Babies Lives bundle in the UK. This makes it a bit harder to evaluate because you don’t know which bits are working and which are not. To date, programs promoting fetal movement monitoring have not been shown to produce the expected outcomes for the fetus / baby (Bellusi, et al., 2020).
Introducing the My Baby’s Movements trial
The latest trial to provide data about the effectiveness or otherwise of fetal movement monitoring is the My Baby’s Movements trial, conducted in Australia and New Zealand. The point of difference for this trial was including a mobile phone app as part of the awareness program used in the intervention arm of the trial. The app prompted women to monitor fetal movements and provided advice about what to do if movement patterns had changed. The findings from the My Baby’s Movements trial have already been published (with no demonstrable reduction in stillbirth), but this new paper from the team specifically focusses on the use of the My Baby’s Movements app.
The research was conducted between 2016 and 2019 in large maternity hospitals. 13,771 women made use of the app, and 126,281 women in the trial who did not use the app served as the control group. Women considered to be higher risk (aged over 35, higher BMI, smokers, giving birth for the first time, Aboriginal women, or those with diabetes and hypertension) were included in the trial.
Stillbirth rates at or after 28 weeks of pregnancy were the same, whether women were allocated to use the app or not, occurring at a rate of 2 per 1000 births in both groups. Rates of suspected small for gestational age or fetal growth reduction were also the same in both groups. A composite measure of neonatal outcome was used – defined as one or more of: neonatal death up to 28 days of life, hypoxic ischaemic encephalopathy, neonatal seizures, meconium aspiration syndrome, cord blood acidosis, incubation and ventilation at birth, any mechanical ventilation, or admission to the nursery in the first 2 days of life. A small but statistically significant reduction in this composite outcome was found, falling from 77 per 1000 births to 72 per 1000 births (adjusted odds ratio 0.87, 95% confidence intervals 0.81 – 0.93). This gives a number needed to treat of 200 (that is 200 women would need to use the app for one baby to avoid having one of these outcomes).
Induction of labour was significantly more common for women allocated to use of the app. 34% of women not using the app had their labour induced, compared with 41% of app users (adjusted odds ratio 1.1, 95% confidence intervals 1.06 – 1.14). This is a number needed to treat of 16 (for every 16 women using the app, one would have an induced labour). There was no significant difference in caesarean section rates (32% in women not using the app and 33% for women using the app). Women using the app were slightly less likely to give birth prior to 37 weeks (6% in app users, 7% in non-users) but slightly more likely to give birth between 37 weeks and 38 weeks and 6 days (32% in app users, 31% in non-users).
The findings from this aspect of the My Baby’s Movements trial add to the existing research base. Others have also found higher rates of induction of labour and a trend towards reduced perinatal morbidity. The studies remain underpowered to be able to reliably show a potential difference in stillbirth rates. When counselling women, it is important not to generate the impression that fetal movement monitoring can guarantee they will avoid a poor outcome.
Bellussi, F., Po, G., Livi, A., Saccone, G., De Vivo, V., Oliver, E. A., & Berghella, V. (2020, Jan 9). Fetal movement counting and perinatal mortality: A systematic review and meta-analysis. Obstetrics & Gynecology, 135(2), 453-462. https://doi.org/10.1097/AOG.0000000000003645
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Categories: antenatal CTG, CTG, New research, Perinatal mortality, Stillbirth
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