Made to move: A review of measurement strategies to characterize heterogeneity in normal fetal movement

Fetal movement is a crucial indicator of fetal well-being. Characteristics of fetal movement vary across gestation, posing challenges for researchers to determine the most suitable assessment of fetal movement for their study. We summarize the current measurement strategies used to assess fetal movement and conduct a comprehensive review of studies utilizing these methods. We critically evaluate various measurement approaches including subjective maternal perception, ultrasound, Doppler ultrasound, wearable technology, magnetocardiograms, and magnetic resonance imaging, highlighting their strengths and weaknesses. We discuss the challenges of accurately capturing fetal movement, which is influenced by factors such as differences in recording times, gestational ages, sample sizes, environmental conditions, subjective perceptions, and characterization across studies. We also highlight the clinical implications of heterogeneity in fetal movement assessment for monitoring fetal behavior, predicting adverse outcomes, and improving maternal attachment to the fetus. Lastly, we propose potential areas of future research to overcome the current gaps and challenges in measuring and characterizing abnormal fetal movement. Our review contributes to the growing body of literature on fetal movement assessment and provides insights into the methodological considerations and potential applications for research.

Effect of encouraging awareness of reduced fetal movement and subsequent clinical management on pregnancy outcome: a systematic review and meta-analysis

OBJECTIVE

Reduced fetal movement, defined as a decrease in the frequency or strength of fetal movements as perceived by the mother, is a common reason for presentation to maternity care. Observational studies have demonstrated an association between reduced fetal movement and stillbirth and fetal growth restriction related to placental insufficiency. However, individual intervention studies have described varying results. This systematic review and meta-analysis aimed to determine whether interventions aimed at encouraging awareness of reduced fetal movement and/or improving its subsequent clinical management reduce the frequency of stillbirth or other important secondary outcomes.

DATA SOURCES

Searches were conducted in MEDLINE, Embase, CINAHL, The Cochrane Library, Web of Science, and Google Scholar. Guidelines, trial registries, and gray literature were also searched. Databases were searched from inception to January 20, 2022.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials and controlled nonrandomized studies were eligible if they assessed interventions aimed at encouraging awareness of fetal movement or fetal movement counting and/or improving the subsequent clinical management of reduced fetal movement. Eligible populations were singleton pregnancies after 24 completed weeks of gestation. The primary review outcome was stillbirth; a number of secondary maternal and neonatal outcomes were specified in the review.

METHODS

Risk of bias was assessed using the Cochrane Risk of Bias 2 and Risk of Bias in Non-Randomized Studies I tools for randomized controlled trials and nonrandomized studies, respectively. Variation caused by heterogeneity was assessed using I². Data from studies employing similar interventions were combined using random effects meta-analysis.

RESULTS

A total of 1609 citations were identified; 190 full-text articles were evaluated against the inclusion criteria, 18 studies (16 randomized controlled trials and 2 nonrandomized studies) were included. The evidence is uncertain about the effect of encouraging awareness of fetal movement on stillbirth when compared with standard care (2 studies, n=330,084) with a pooled adjusted odds ratio of 1.19 (95% confidence interval, 0.96-1.47). Interventions for encouraging awareness of fetal movement may be associated with a reduction in neonatal intensive care unit admissions and Apgar scores of <7 at 5 minutes of age and may not be associated with increases in cesarean deliveries or induction of labor. The evidence is uncertain about the effect of encouraging fetal movement counting on stillbirth when compared with standard care with a pooled odds ratio of 0.69 (95% confidence interval, 0.18-2.65) based on data from 3 randomized controlled trials (n=70,584). Counting fetal movements may increase maternal-fetal attachment and decrease anxiety when compared with standard care. When comparing combined interventions of fetal movement awareness and subsequent clinical management with standard care (1 study, n=393,857), the evidence is uncertain about the effect on stillbirth (adjusted odds ratio, 0.86; 95% confidence interval, 0.70-1.05).

CONCLUSION

The effect of interventions for encouraging awareness of reduced fetal movement alone or in combination with subsequent clinical management on stillbirth is uncertain. Encouraging awareness of fetal movement may be associated with reduced adverse neonatal outcomes without an increase in interventions in labor. The meta-analysis was hampered by variations in interventions, outcome reporting, and definitions. Individual studies are frequently underpowered to detect a reduction in severe, rare outcomes and no studies were included from high-burden settings. Studies from such settings are needed to determine whether interventions can reduce stillbirth.

Development of a core outcome set (COS) for studies relating to awareness and clinical management of reduced fetal movement: study protocol

BACKGROUND

Concerns regarding reduced fetal movements (RFM) are reported in 5-15% of pregnancies, and RFM are associated with adverse pregnancy outcomes including fetal growth restriction and stillbirth. Studies have aimed to improve pregnancy outcomes by evaluating interventions to raise awareness of RFM in pregnancy, such as kick counting, evaluating interventions for the clinical management of RFM, or both. However, there is not currently a core outcome set (COS) for studies of RFM. This study aims to create a COS for use in research studies that aim to raise awareness of RFM and/or evaluate interventions for the clinical management of RFM.

METHODS

A systematic review will be conducted, to identify outcomes used in randomised and non-randomised studies with control groups that aimed to raise awareness of RFM (for example by using mindfulness techniques, fetal movement counting, or other tools such as leaflets or mobile phone applications) and/or that evaluated the clinical management of RFM. An international Delphi consensus will then be used whereby stakeholders will rate the importance of the outcomes identified in the systematic review in (i) awareness and (ii) clinical management studies. The preliminary lists of outcomes will be discussed at a consensus meeting where one final COS for awareness and management, or two discrete COS (one for awareness and one for management), will be agreed upon.

DISCUSSION

A well-developed COS will provide researchers with the minimum set of outcomes that should be measured and reported in studies that aim to quantify the effects of interventions.