12 Monitoring Twin FHRs
The fetal sensor socket to which a transducer is connected is identified by the transducer position
indicator in the setup menu header:
The trace recorded for FHR1 is thicker (darker) than that recorded for FHR2. This ensures that
the two heart rates are easily distinguishable. The thickness of the recorded trace can be changed in
Remember that only one fetal heartbeat can be heard from the loudspeaker at a time.
The audio source symbol shows you which fetus you are listening to. To hear the other fetal
heartbeat, select the fetal heart rate sound for this channel (see "Selecting Fetal Heart Sound" on
Monitor maternal pulse, especially during later stages of labor, to avoid mistaking maternal heart
rate for FHR.
Make sure you are recording the best possible signals by referring to the signal quality indicators
and repositioning the transducers if necessary.
For the Avalon CL transducer system see "Cableless Monitoring - Important Considerations" on
Monitoring Twins Externally
To monitor twin FHRs externally you need two ultrasound transducers. Follow the procedures
described in "Monitoring FHR and FMP Using Ultrasound" on page 141. The transducer Finder LED
lets you identify at a glance which transducer is monitoring which FHR channel, and lights when you
select the FHR numeric field on the screen.