Technical Update No. 429: Maternal Heart Rate Artefact During Intrapartum Fetal Health Surveillance

Objective: To improve perinatal outcomes and minimize provider error by increasing awareness of strategies to detect intrapartum maternal heart rate artefact and to respond when such artefact is suspected.

Target population: All pregnant patients during labour.

Options: Maternal heart rate artefact may be detected based on clinical features or through technology. Suspected maternal heart rate artefact may be assessed by applying a fetal scalp electrode (preferred) or through external fetal monitoring, augmented by point-of-care sonography (alternative).

Outcomes: Unrecognized intrapartum maternal heart rate artefact increases the risk that abnormal/atypical fetal heart rate patterns will go undetected and, hence, the risk of adverse perinatal outcomes.

Benefits, harms, and costs: Unrecognized maternal heart rate artefact can lead to adverse perinatal outcomes (hypoxic-ischemic encephalopathy, fetal death, and neonatal death) and adverse maternal outcomes (unnecessary cesarean delivery or operative vaginal delivery). Timely recognition of such artefact may avoid these adverse outcomes. The costs of early recognition of maternal heart rate artefact are relatively small: increased use of fetal scalp electrodes and point-of-care sonography, as well as additional assessments by the health care provider. The cost savings are significant, as a result of lower risk of adverse perinatal outcomes. Potential harms are false-positive diagnoses of maternal heart rate artefact, expediting delivery unnecessarily when the fetal status cannot be reliably determined but is normal, and the rare complications associated with increased use of fetal scalp electrodes.

Evidence: Two PubMed searches were completed. The first was for articles published between January 1, 1970, and November 25, 2021, using the medical subject headings (MeSH) "fetal monitoring" and "artifacts" (38 articles). The second was for articles published during the same period using the MeSH "fetal monitoring" and "maternal heart rate" (841 articles).

Validation methods: The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

Intended audience: All health care providers involved in obstetrical care.

Summary statements: RECOMMENDATIONS.