The FDA has issued a letter to notify healthcare professionals and facilities of a number of complaints of inaccurate readings when using the Philips Healthcare Avalon fetal monitors, models FM20, FM30, FM40, and FM50 with the ultrasound transducer to measure fetal heart rate.

On Sept. 4, Philips issued an important device safety alert. Inaccurate output readings, if not properly addressed, may lead to unnecessary interventions, failure to identify the need for interventions and failure to identify fetal distress, according to the company.

The complaints most commonly occur during the second stage of labor, the agency reported. Philips received a number of complaints of inaccurate output readings that prompted this alert.