In pregnancies progressing beyond 41 weeks (prolonged pregnancy), women and their care providers often seek reassurance of fetal wellbeing to support continuing pregnancy. CTG monitoring is often advised, though there has never been a randomised controlled trial designed specifically to answer this question. Some of the women included in antenatal CTG trials summarised in the Cochrane review had prolonged pregnancies but they were mixed in with other women with different risk factors so we can’t tell whether there was any advantage to CTG monitoring for this population. Overall, antenatal CTG monitoring is associated with an increased, but not statistically significant, incidence of perinatal mortality and no change in the caesarean section rate (Grivell, et al., 2015). You can read more about that here.
Another approach, one that is so commonly accepted we rarely think of it as an intervention, is to ask women to monitor fetal movements. Like so many interventions in pregnancy aimed at reducing mortality, this seems like a great idea. Several randomised controlled trials of fetal movement awareness campaigns have however shown no improvement in perinatal mortality. I have written about some of these here. A new paper, published just before Christmas 2022, focussed on the question of whether promoting awareness of fetal movements improved perinatal outcomes specifically for women with prolonged pregnancy (Moniod, et al., 2022).
This trial, called the COMPTAMAF study, was conducted in France between 2019 and 2022. Women who were 41 weeks or more pregnant with no pregnancy complications (such as “unbalanced” diabetes, pregnancy induced hypertension, preeclampsia, cholestasis, or fetal growth restriction) were recruited. Women in the control group were given a flyer advising them to seek advice if they noted a reduction in movements. Women in the treatment group were also given a flyer but this time it provided detailed information about what fetal movements were, the technique for counting movements, a chart to record the movement count at three times during the day, and instructions on what to do if movements were reduced.
Both cohorts had CTG monitoring every second day, along with a clinical assessment. Induction of labour was offered at 41 weeks and 5 days, aiming to achieve birth prior to 42 weeks of gestation. 281 women were randomised, with data available for 131 in the control group and 129 in the treatment group. There were no significant differences between the two groups with respect to age, BMI, parity, previous mode of birth, smoking status, or gestational diabetes.
The primary outcome measure was a composite made up of abnormal fetal heart rate, Apgar score of less than seven at five minutes of age, arterial cord blood gas under 7.2, and respiratory distress managed in the neonatal care unit. There was no significant difference in the incidence of the primary outcome between the control group (23%) and the fetal monitoring group (14%), nor in any of these outcomes individually. No stillbirths occurred.
There were no differences in the rate of consultations for reduced movements between the two cohorts. No were there differences in the mode of labour onset, mode of birth, or the reasons for instrumental or caesarean birth. The authors also look at other factors that impacted on the primary outcome. Primiparity, induction of labour, instrumental birth, and caesarean birth were associated with higher rates of the primary outcome.
This study joins previous randomised trials that similarly failed to demonstrate that a focus on fetal movement monitoring improves perinatal outcomes.
References
Grivell, R. M., Alfirevic, Z., Gyte, G. M. L., & Devane, D. (2015, Jun 26). Antenatal cardiotocography for fetal assessment. Cochrane Database of Systematic Reviews, 9(9), CD007863. https://doi.org/10.1002/14651858.CD007863.pub4
Moniod, L., Hovine, A., Trombert, B., Rancon, F., Zufferey, P., Chauveau, L., Chauleur, C., & Raia-Barjat, T. (2022, Dec 18). Fetal movement counting in prolonged pregnancies: The COMPTAMAF prospective randomized trial. Healthcare, 10(12). https://doi.org/10.3390/healthcare10122569
Categories: CTG
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