FETAL DOPPLER
The Fetal Doppler listens to reflections of small, high frequency sound waves that are reflected off of the fetal heart. Since high frequency sound waves do not travel readily through air, ultrasound gel is applied to it in order for the doppler's probe to detect these sound waves. These signals are picked up, processed, and amplified so that they are audible in the fetal doppler's speaker allowing one to hear the baby's heartbeat.
PALPATION
Palpation- the clinician can provide a decent interpretation of contractions by placing a hand on the uterine fundus- the top of the gravid abdomen. The clinician will be able to palpate as the uterus tightens with the contraction. A practiced hand will be able to describe the contractions as mild, moderate, or strong in intensity. Mild contraction –uterus is easily intended (like the tip of the nose). Moderate contraction- uterus can slightly indent (like the chin). Strong contraction- uterus cannot be indented (like the forehead)
CONTINUOUS ELECTRONIC FETAL MONITORING
Belts are placed around the maternal abdomen to keep external monitors in place for continuous monitoring of contractions and fetal heart rate.
-TRANSABDOMINAL ULTRASOUND
Ultrasound- Ultrasound discs can be placed on maternal gravid abdomen to trace fetal heart rate externally. The u/s generates sound waves that reflect back from the fetal heart movement. The computer interprets these sound waves and presents a sound and continuous tracing.
-TOCODYNAMOMETER
Tocodynamometer (a.k.a. “Toco”) - Pressure sensitive device that is placed on maternal fundus to trace contractions. The resulting tracing read from abdominal wall tenseness, measuring frequency and duration. The toco does not provide information on contraction intensity. Palpation should be added to further evaluate contractions.
Some things I have noted with the toco is the lack of consistent tracings. I often tell my patients that if they feel contractions, I would believe them before I believe the monitor because of this inconsistency. If a patient has a great deal of fatty tissue covering the uterus, the toco may not be able to pick up the uterine changes. The same can be noted if the patient is laying on their side, the contractions may not pick up. Maternal movement and position, toco positioning and placement, coughing, sneezing, vomiting, pushing… will all effect the toco making contraction tracings higher, lower, or provide spiking movements on the tracing.
Some things I have noted with the toco is the lack of consistent tracings. I often tell my patients that if they feel contractions, I would believe them before I believe the monitor because of this inconsistency. If a patient has a great deal of fatty tissue covering the uterus, the toco may not be able to pick up the uterine changes. The same can be noted if the patient is laying on their side, the contractions may not pick up. Maternal movement and position, toco positioning and placement, coughing, sneezing, vomiting, pushing… will all effect the toco making contraction tracings higher, lower, or provide spiking movements on the tracing.
-INTERNAL FETAL SPIRAL ELECTRODE (FSE)
Fetal Spiral Electrode- Internal electrode placed on fetal scalp to trace fetal heart rate. This would require rupture of membranes. This also causes a small open scratch on top of the baby’s head that could lead to infection. The electronic logic provides detection of R-to-R waves in QRS to obtain the fetal heart rate.
-INTRAUTERINE PRESSURE CATHETER (IUPC)
Intrauterine Pressure Catheter (a.k.a. “IUPC”)- This device is used in about 20% of labors and requires rupture of membranes. The IUPC will provide a quantitative measurement of contractions’ frequency, duration, and intensity. The IUPC is a small tube that is inserted into the uterine cavity, next to the baby, during a cervical exam. Some indications for use of this more invasive measure are- 1) Need for quantitative analysis of contractions, ie. Are the contractions strong enough for adequate labor? 2) Need for amnioinfusion- fluid can flow through this tube to help alleviate some cord compression. 3) External toco is not providing a readable tracing when oxytocin is in use.