Fetal vibroacoustic stimulation for facilitation of tests of fetal wellbeing

RHL summary

21 October 2013
A doctors uses a foetal stethoscope to examine a pregnant woman during a routine prenatal check-up, Pakistan.
UNICEF/Marta Ramoneda

Findings of the review: Antenatal fetal heart rate (FHR) testing can be costly in terms of staff time if the fetus spends up to 40 minutes in a quiet sleep state yielding a non-reactive fetal heart rate (FRH) pattern. Vibroacoustic stimulation “wakes up” the fetus and shortens the testing time by eliciting a fetal movement and heart rate accelerations. In nine randomized trials with 4838 women, vibroacoustic stimulation reduced the rate of non-reactive (abnormal) FHR tests by between 25% and 50%, and reduced the testing time by 10 minutes.

Implementation: Before vibroacoustic stimulation can recommended for routine use, more evidence on safety is needed. The possibility of clinical fetal assessment with perceived movements or auscultated FHR accelerations in response to vibroacoustic stimulation has important implications for settings without cardiotocograph facilities.


Cochrane review

Citation: Tan KH, Smyth RMD. Fetal vibroacoustic stimulation for facilitation of tests of fetal wellbeing. Cochrane Database of Systematic Reviews 2001, Issue 1. Art. No.: CD002963. DOI: 10.1002/14651858.CD002963.

Abstract

Background

Acoustic stimulation of the fetus has been suggested to improve the efficiency of antepartum fetal heart rate testing.

Objectives

To assess the merits or adverse effects of the use of fetal vibroacoustic stimulation in conjunction with tests of fetal well-being.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2003). We updated this search on 1 October 2009 and added the results to the awaiting classification section.

Selection criteria

All published and unpublished randomized controlled trials assessing the merits of the use of fetal vibroacoustic stimulation in conjunction with tests of fetal well-being.

Data collection and analysis

Both reviewers independently extracted data and assessed trial quality. Authors of published and unpublished trials were contacted for further information.

Main results

A total of nine trials with a total of 4838 participants were included. Fetal vibroacoustic stimulation reduced the incidence of non-reactive antenatal cardiotocography test (seven trials; relative risk (RR) 0.62, 95% confidence interval (CI) random 0.52 to 0.74) and reduced the overall mean cardiotocography testing time (three trials; weighted mean difference (WMD) -9.94 minutes, 95% CI -9.37 minutes to -10.50 minutes). Vibroacoustic stimulation compared with mock stimulation evoked significantly more fetal movements when used in conjunction with fetal heart rate testing (one trial, RR 0.23, 95% CI 0.18 to 0.30).

Authors' conclusions

Vibroacoustic stimulation offers benefits by decreasing the incidence of non-reactive cardiotocography and reducing the testing time. Further randomized trials should be encouraged to determine not only the optimum intensity, frequency, duration and position of the vibroacoustic stimulation, but also to evaluate the efficacy, predictive reliability, safety and perinatal outcome of these stimuli with cardiotocography and other tests of fetal well-being.

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