(Fetal Monitoring, External and Internal) Show
Procedure OverviewWhat is external and internal fetal heart rate monitoring?Fetal heart rate monitoring is a procedure used to evaluate the well-being of the fetus by assessing the rate and rhythm of the fetal heartbeat. During late pregnancy and labor, your physician may recommend monitoring the fetal heart rate and other functions. The average fetal heart rate is between 110 and 160 beats per minute, and can vary five to 25 beats per minute. The fetal heart rate may change as the fetus responds to conditions in the uterus. An abnormal fetal heart rate or pattern may indicate that the fetus is not getting enough oxygen or that there are other problems. There are two methods for fetal heart rate monitoring, external and internal:
During labor, uterine contractions are usually monitored along with the fetal heart rate. A pressure-sensitive device called a tocodynamometer is placed on the mother's abdomen over the area of strongest contractions to measure the length, frequency, and strength of uterine contractions. Because the fetal heart rate and uterine contractions are recorded at the same time, these results can be examined together and compared. Internal uterine pressure monitoring is sometimes used along with internal fetal heart rate monitoring. A fluid-filled catheter is placed through the cervical opening into the uterus beside the fetus and transmits uterine pressure readings to the monitor. Other procedures that may be used to monitor the well-being of the fetus include amniocentesis and chorionic villus sampling. Please see these procedures for additional information. Anatomy of the fetus:
Reasons for the ProcedureFetal heart rate monitoring is used in nearly every pregnancy to assess fetal well-being and identify any changes that might be associated with problems during pregnancy or labor. Fetal heart rate monitoring is especially helpful for high-risk pregnancy conditions such as diabetes, high blood pressure, and problems with fetal growth. Situations during pregnancy in which fetal heart rate monitoring may be used include, but are not limited to, assessment of fetal heart rate during prenatal physician visits and monitoring the effect of preterm labor medications on the fetus. Fetal heart rate monitoring may be used as a component of other procedures, including, but not limited to, the following:
Situations during labor which may affect the fetal heart rate and for which fetal heart rate monitoring may be used include, but are not limited to, the following:
There may be other reasons for your physician to recommend fetal heart rate monitoring. Risks of the ProcedureThere is no radiation used and generally no discomfort from the application of the transducer to the abdominal skin. The elastic belts that hold the ultrasound and pressure transducers in place around your abdomen may be slightly uncomfortable. These can be readjusted to help you feel more comfortable. You must lie still during some types of fetal heart rate monitoring. You may be required to stay in bed during labor. With internal monitoring, you may experience some slight discomfort during the insertion of the electrode. Risks of internal monitoring include, but are not limited to, infection and bruising of the fetal scalp or other body part. Internal fetal heart rate monitoring is contraindicated in women with active herpes lesions on the cervix or vagina because of the risk of transferring the infection to the fetus. There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure. Certain factors or conditions may interfere with the results of the procedure. These include, but are not limited to, the following:
Before the Procedure
During the ProcedureFetal heart rate monitoring may be performed in your physician's office, on an outpatient basis, or as part of your stay in a hospital. Procedures may vary depending on your condition and your hospital's practices. Generally, fetal heart rate monitoring follows this process: For external fetal heart rate monitoring:
For internal fetal heart rate monitoring:
After the ProcedureThere is no special type of care required after external fetal heart rate monitoring. You may resume your normal diet and activity unless your physician advises you differently. After internal fetal heart rate monitoring, the electrode site on the newborn baby will be examined for infection, bruising, or a laceration. The site may be cleansed with an antiseptic. Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation. Online ResourcesThe content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. Please consult your physician with any questions or concerns you may have regarding your condition. This page contains links to other Web sites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these Web sites, nor do these sites endorse the information contained here. American College of Obstetricians and Gynecologists American Institute of Ultrasound in Medicine National Institutes of Health (NIH) National Library of Medicine National Women's Health Information Center What prenatal test uses high frequency sound waves?Ultrasound uses high frequency sound waves and their echoes to make cross-sectional images of the fetus. Ultrasound produces no radiation and is painless.
What is the use of high frequency sound waves to view the fetus in the uterus?In ultrasonography, or ultrasound, high-frequency sound waves are sent through your abdomen by a device called a transducer. The sound waves are recorded and changed into video or photographic images of your baby. The ultrasound can be used during pregnancy to show images of the amniotic sac, placenta, and ovaries.
What prenatal technique can be used to examine the status of the fetus?Amniocentesis. An amniocentesis is a prenatal test that allows information about the baby to be obtained from the amniotic fluid. This test can be done any time after the 15th week of gestation.
What prenatal technique can be used to examine the status of the fetus by taking samples of the cells that are beginning to form the umbilical cord?Chorionic villus sampling (CVS), or chorionic villus biopsy, is a prenatal test that involves taking a sample of tissue from the placenta to test for chromosomal abnormalities and certain other genetic problems.
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