How well can the fetal heart rate baseline be assessed by intrapartum intermittent auscultation? An interrater reliability and agreement study

Background

We aimed to examine the inter-reliability and agreement among midwives when assessing the fetal heart rate (FHR) using the handheld Doppler. The primary aim was to measure the reliability and agreement of FHR baseline (baseline) as beats per minute (bpm). The secondary aims were to measure fluctuations from the baseline, defined as increases and decreases, and classifications (normal or abnormal) of FHR soundtracks. This is the first interrater reliability and agreement study on intermittent auscultation (IA) to our knowledge.

Methods

The participant population consisted of 154 women in labor, from a mixed-risk population and admitted to hospital for intrapartum care. The rater population were 16 midwives from various maternity care settings in Norway. A total of 154 soundtracks were recorded with a handheld Doppler device, and the 16 raters assessed 1-min soundtracks once, through an online survey (Nettskjema). They assessed the baseline, FHR increase or decrease, and the FHR classification. The primary outcome, baseline, was measured with intraclass correlation coefficient (ICC). The secondary outcomes were measured with kappa and proportion of agreement.

Results

The interrater reliability for the baseline (bpm) was ICC(A,1) 0.74 (95% CI 0.69–0.78). On average, an absolute difference of 7.9 bpm (95% CI 7.3–8.5 bpm) was observed between pairs of raters.

Conclusion

Our results demonstrate an acceptable level of reliability and agreement in assessing the baseline using a handheld Doppler.