OBSTETRIC TECHNOLOGY
Fetal Monitoring
In the 20th century , methods of monitoring the fetal heart rate and uterine contractions were developed . This information is recorded on graph paper or electronically , with the fetal heart rate at the top and the contractions shown at the bottom .
• External Monitors – For external monitoring , an ultrasound transducer measures the baby ’ s heart rate , while a pressure sensor called a tocodynamometer records contractions . The monitors , placed on the mother ’ s abdomen , are non-invasive and painless . The external contraction monitor records intervals between contractions but does not measure contraction strength .
• Internal Monitors – After the amniotic sac breaks during labor , your physician may place internal monitors . A fetal scalp electrode provides an accurate recording of your baby ’ s heartbeat by using a fine wire attached to the baby ’ s scalp . An intrauterine pressure catheter ( IUPC ), a thin tube that contains a pressure sensor and is placed within the uterus , measures how strong your contractions are . Internal monitors let your doctor know how well your labor is progressing and how well the baby is tolerating the labor process .
34 My Prenatal Care Book