Use of a pocket-device point-of-care ultrasound to assess cervical dilation in labor: correlation and patient experience.

OBJECTIVES: To estimate the correlation of cervical dilation between pocket-device point-of-care transperineal ultrasound (TPUS) and digital cervical examination (DCE).

METHODS: Laboring pregnant individuals ≥37 weeks of gestation presenting were prospectively evaluated for cervical dilation with a handheld pocket-sized ultrasound (Butterfly iQ+® ) applied to the perineum, with a blinded DCE directly following. Subjects completed a survey to rate pain and for any preference from the examinations. To detect a moderate correlation (r=0.5) between TPUS and DCE, with an alpha of 0.05 and power of 80%, a sample size of 30 examinations were needed.

RESULTS: From April 2022 to July 2022, 30 pregnant individuals were assessed. The median cervical dilation by TPUS vs. DCE was 5.1 and 5 cm, respectively, with a Pearson's correlation coefficient, r=0.86 (95% CI 0.72 to 0.93), p<0.001. Transperineal ultrasound had a significantly less pain score than DCE, median pain score 0 vs. 2 for TPUS and DCE respectively, p<0.001. All individuals preferred the TPUS over the DCE.

CONCLUSIONS: Measurement of cervical dilation using a pocket-device point-of-care TPUS has a strong positive correlation with DCE and offers a non-invasive, convenient alternative to traditional digital exams in term, laboring patients.