Fetal Heart Rate Patterns Mnemonic
Author: Georgina Tiarks
Editors: Alyssa Haag, Ian Mannarino, MD, MBA, Kelsey LaFayette, DNP, RN
Illustrator: Jessica Reynolds, MS
Copyeditor: David G. Walker
What is VEAL CHOP?
VEAL CHOP is a mnemonic used to remember the various fetal heart rate patterns and their respective causes. The VEAL portion of the mnemonic represents fetal heart rate (FHR) acceleration (i.e., increases in FHR) and deceleration patterns (i.e., decreases in FHR). While the CHOP portion represents the causes of these accelerations and decelerations. The words are commonly pictured side-by-side so the effect is located adjacent to its cause (e.g., V pairs with C, E pairs with H, and so on). For example, V stands for variable decelerations, which is caused by the C, representing cord compression.
How are fetal heart rates monitored?
Fetal heart rates can be monitored via auscultation (i.e., listening to internal organs) with a stethoscope or by using an electronic fetal monitor device. During office visits, a healthcare provider may use auscultation as a technique to listen to a fetal heart rate, whereas in high-risk pregnancies (i.e., any pregnancy that requires close monitoring to reduce the chance of complications) or in the hospital, an electronic fetal monitor may be utilized instead.Electronic fetal monitors can be either internal or external. Internal monitors may use an electrode that is inserted into the uterus and placed on the fetus’ scalp with an intrauterine pressure catheter also placed into the uterus to measure the contractions. The internal method can only be used once the amniotic sac has ruptured, which is colloquially known as when the individual's “water breaks.” In comparison, the external method uses two transducers. One ultrasound transducer is placed on the abdomen near where the fetus is located, which can record the fetal heart rate. The other transducer is placed near the top of the abdomen to record uterine contractions. Both devices are held in place on the abdomen using elastic belts. On the monitor, both the fetal heart rate and the maternal contractions will be visually apparent and tracked.
What does VEAL CHOP mean?
VEAL CHOP is a mnemonic that represents the types and causes of fetal heart rate acceleration and deceleration patterns. It is used by healthcare providers to remember fetal heart rate patterns and their causes.
V stands for variable decelerations, which are defined as a change in the FHR from baseline by more than 15 beats per minute (BPM), lasting between 15 seconds and two minutes. Variable decelerations typically occur during the onset of a contraction and reach its lowest BPM (i.e., nadir) in less than 30 seconds. However, they can also be episodic and unrelated to contractions.
E stands for early decelerations. Early decelerations are fetal heart rate decelerations that occur during a contraction. Most often, there is a gradual decrease in fetal heart rate which then returns to baseline within 30 seconds of the conclusion of the contraction. These decelerations are often considered benign (i.e., no threat to the fetus).
A stands for acceleration. Accelerations often last greater than 15 seconds but less than two minutes. These may peak greater than 15 BPM higher than the fetal baseline heart rate.
L stands for late decelerations. Late decelerations represent decelerations that start to gradually decline during or after the contraction. These decelerations recover to baseline after the contraction has ended. The lowest point (i.e., nadir) typically occurs greater than 30 seconds after the onset.
C stands for cord compression and is the cause of variable decelerations. When the cord is compressed, the umbilical vein may be flattened. This results in decreased fetal preload (i.e., blood return) to the heart, which causes baroreceptor-mediated reflex tachycardia (i.e., increase in fetal heart rate). Subsequently, there is an increase in fetal blood pressure in the carotids, which in turn, causes vagal stimulation to slow the heart rate, causing bradycardia (i.e., low heart rate). When the contraction stops, the physiologic fetal heart rate returns to baseline.
H stands for head compression. Head compression results in a Cushing response, which results in increased intracranial pressure and decreased cerebral blood flow. This elevated pressure triggers vagal activation, which subsequently, decreases the fetal heart rate, thereby causing bradycardia. This mechanism is responsible for the early decelerations seen on electronic fetal heart rate monitors.
O stands for “okay” or “oxygen is good!” This part of the mnemonic matches accelerations. Fetal heart rate accelerations are often due to fetal movement, scalp stimulation, stimulation by contractions, or acoustic stimulation. These patterns on the fetal monitor are common and reassuring.P stands for placental insufficiency. Placental dysfunction can cause late decelerations on the fetal heart rate monitor and may represent inadequate uterine perfusion, excessive uterine activity, maternal hypotension, and fetal hypoxia. In some cases, abruptio placenta (i.e., early separation of the placenta from uterus) can cause late decelerations.
What are the most important facts to know about the VEAL CHOP mnemonic?
VEAL CHOP is a medical and nursing mnemonic used to remember fetal heart rate patterns and their causes. Fetal heart rate can be monitored through auscultation by a healthcare provider or by using an electronic fetal heart rate monitor, which records both the fetal heart rate and the mother’s contractions. The VEAL in VEAL CHOP represents the acceleration and deceleration patterns seen on the monitor, while CHOP represents the subsequent causes. The “\V stands for variable decelerations, which is typically caused by C for cord compression. E stands for early decelerations caused by H for head compression. A is for accelerations, which corresponds to O, for okay or good oxygen. Finally, L represents late decelerations, which is caused by placental insufficiency for P.
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Resources for research and reference
Choe, J., Shanks, A. L., & Mahdy, H. (2022). Early Decelerations. In StatPearls. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK557393/
Cunningham, F. G., Leveno, K. J., Dashe, J. S., Hoffman, B. L., Spong, C. Y., & Casey, B. M. (2022). Intrapartum Assessment. In Williams Obstetrics (26th ed.). McGraw Hill. Retrieved from accessmedicine.mhmedical.com/content.aspx?aid=1188270877
Fetal Heart Monitoring. In Stanford Children’s Health. Retrieved April 8, 2022, from https://www.stanfordchildrens.org/en/topic/default?id=external-and-internal-heart-rate-monitoring-of-the-fetus-92-P07776
Fetal Heart Rate Monitoring During Labor. (2018). In The American College of Obstetricians and Gynecologists. Retrieved April 8, 2022, from https://www.acog.org/en/womens-health/faqs/fetal-heart-rate-monitoring-during-labor
Sung, S., & Abramovitz, A. (2022). Variable Decelerations. In StatPearls. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK546627/Sweha, A., Hacker, T. W., & Nuovo, J. (1999). Interpretation of the Electronic Fetal Heart Rate During Labor. American Family Physician, 59(9), 2487.