What type of monitoring technique uses a transducer placed on the mother's abdomen?

External monitoring is the correct answer in this context because it specifically refers to the use of a transducer that is placed on the mother's abdomen to assess the fetal heart rate and uterine contractions. This non-invasive method allows healthcare providers to continuously monitor the baby’s heart rate patterns during labor and delivery. The external fetal monitor typically uses a Doppler ultrasound technique to obtain these readings, making it a common practice in various clinical settings.

This technique is advantageous as it allows for mobility in patients since it does not require any invasive procedures. The data collected can give insights into fetal well-being, aiding in the evaluation of the fetal condition throughout labor.

In contrast, internal monitoring involves placing a device inside the uterus to get a more accurate measurement of the fetal heart rate and uterine contractions, typically using a fetal scalp electrode. Scalp sampling is a different technique used to assess blood gases from the fetal scalp, and dynamic monitoring isn’t a standard term associated with fetal monitoring techniques.