Table of ContentsView AllTable of ContentsAccelerationsDecelerationsWhat to ExpectBenefits
Table of ContentsView All
View All
Table of Contents
Accelerations
Decelerations
What to Expect
Benefits
Changes in fetal heart rate during late pregnancy or labor can be normal, but they can also indicate a problem for the fetus or the mother. Specific patterns of deceleration, such as late deceleration, can be signs of fetal distress, which may require emergency interventions, such as a Cesarean section delivery (C-section).
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What’s a normal heart rate?Fetal heart rate (FHR) can be detected from approximately 6 weeks gestation. There is some variation in what experts consider the “normal” baseline for FHR, but it’s generally accepted to range from 110 bpm to 160 bpm.FHR generally decreases as the pregnancy goes on.
What’s a normal heart rate?
Fetal heart rate (FHR) can be detected from approximately 6 weeks gestation. There is some variation in what experts consider the “normal” baseline for FHR, but it’s generally accepted to range from 110 bpm to 160 bpm.FHR generally decreases as the pregnancy goes on.
What Is a Normal Fetal Heart Rate During Pregnancy?
When you are in labor, your healthcare provider will use different methods to keep track of the fetal heart rate. Accelerations may occur at different times throughout labor and delivery and are a sign that the fetus has an adequate supply of oxygen.
Deceleration occurs when the FHR temporarily slows during labor.Three types of deceleration may occur: early, late, and variable. While early decelerations are usually normal, late and variable decelerations can point to a problem.
Early Deceleration
Early deceleration describes the symmetrical decreases and return-to-normal of the fetal heart rate that is linked touterine contractions. The decrease in heart rate occurs gradually.
With early decelerations, the point when the fetal heart rate is at its slowest (called thenadir) and the peak of the uterine contraction happen at the same time.Therefore, the fetal heart rate is recorded at its lowest rate for 30 seconds (or longer) at the beginning of the early deceleration cycle.
Thevagal responseoccurs when there is stimulation of the vagus nerve. The stimulation can lead to physical symptoms in the body, such as:A decrease in blood flow to the brainA low heart rateLow blood pressure
Thevagal responseoccurs when there is stimulation of the vagus nerve. The stimulation can lead to physical symptoms in the body, such as:
Late Deceleration
Usually, the onset of low fetal heart rate, the nadir, and the recovery coincide with the contraction’s onset, peak, and end.
Variable Deceleration
A variable deceleration is a very quick decrease in fetal heart rate of 15 bpm or more, that lasts at least 15 seconds (but may last up to two minutes) before the heart rate returns to baseline.
The onset of fetal slow heart rate, as well as the durationof the decelerations, varies with uterine contractions.
When Does the Fetal Heart Rate Slow Down?Between the fifth and seventh week of pregnancy, the fetal heart rate is typically between 90 and 110 beats per minute. Between weeks 8 and 12, the heart rate speeds up to between 140 and 170 beats per minute. By week 12, it starts to slow down and usually remains at around 110 to 160 beats per minute until the 26th week. It may slow down a little more during the last 10 weeks of pregnancy.
When Does the Fetal Heart Rate Slow Down?
Between the fifth and seventh week of pregnancy, the fetal heart rate is typically between 90 and 110 beats per minute. Between weeks 8 and 12, the heart rate speeds up to between 140 and 170 beats per minute. By week 12, it starts to slow down and usually remains at around 110 to 160 beats per minute until the 26th week. It may slow down a little more during the last 10 weeks of pregnancy.
What to Expect From Fetal Heart Monitoring
The devices used to monitor fetal heart rate during labor can be internal or external.
The Benefits and Risks of Fetal Monitoring
Electronic fetal heart rate monitoring can be used to evaluate the overall health of the fetus during labor. The primary benefit of monitoring is early detection of fetal distress, but there is also a risk of false-positive interpretations of the readings (also called tracings).
The fetal heart rate undergoes continuous stimuli adjustments (such as from contractions). The outcome of the readings are categorized in one of three ways:
However, the inconsistent interpretation of the FHR readings can cause false-positive ominous readings, which could lead to unnecessary emergency interventions, such as a C-section.
Summary
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Johns Hopkins Medicine.Fetal heart monitoring.MedlinePlus.Nonstress test.Sholapurkar SL.Categorization of fetal heart rate decelerations in American and European practice: importance and imperative of avoiding framing and confirmation biases.J Clin Med Res. 2015;7(9):672-680. doi:10.14740/jocmr2166wOxford Academic Health Science Network Maternity.Oxford AHSN Cardiotocograph (CTG) Interpretation Tool Definitions.Chuai F, Dong T, Liu Y, et al.The effect of intrapartum prolonged oxygen exposure on fetal metabolic status: Secondary analysis from a randomized controlled trial.Front Endocrinol (Lausanne). 2023;14:1204956. doi:10.3389/fendo.2023.1204956American Pregnancy Association.Early fetal development.Gravett C, Eckert LO, Gravett MG, et al.Non-reassuring fetal status: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data.Vaccine. 2016;34(49):6084-6092. doi:10.1016/j.vaccine.2016.03.043
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Johns Hopkins Medicine.Fetal heart monitoring.MedlinePlus.Nonstress test.Sholapurkar SL.Categorization of fetal heart rate decelerations in American and European practice: importance and imperative of avoiding framing and confirmation biases.J Clin Med Res. 2015;7(9):672-680. doi:10.14740/jocmr2166wOxford Academic Health Science Network Maternity.Oxford AHSN Cardiotocograph (CTG) Interpretation Tool Definitions.Chuai F, Dong T, Liu Y, et al.The effect of intrapartum prolonged oxygen exposure on fetal metabolic status: Secondary analysis from a randomized controlled trial.Front Endocrinol (Lausanne). 2023;14:1204956. doi:10.3389/fendo.2023.1204956American Pregnancy Association.Early fetal development.Gravett C, Eckert LO, Gravett MG, et al.Non-reassuring fetal status: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data.Vaccine. 2016;34(49):6084-6092. doi:10.1016/j.vaccine.2016.03.043
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Johns Hopkins Medicine.Fetal heart monitoring.MedlinePlus.Nonstress test.Sholapurkar SL.Categorization of fetal heart rate decelerations in American and European practice: importance and imperative of avoiding framing and confirmation biases.J Clin Med Res. 2015;7(9):672-680. doi:10.14740/jocmr2166wOxford Academic Health Science Network Maternity.Oxford AHSN Cardiotocograph (CTG) Interpretation Tool Definitions.Chuai F, Dong T, Liu Y, et al.The effect of intrapartum prolonged oxygen exposure on fetal metabolic status: Secondary analysis from a randomized controlled trial.Front Endocrinol (Lausanne). 2023;14:1204956. doi:10.3389/fendo.2023.1204956American Pregnancy Association.Early fetal development.Gravett C, Eckert LO, Gravett MG, et al.Non-reassuring fetal status: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data.Vaccine. 2016;34(49):6084-6092. doi:10.1016/j.vaccine.2016.03.043
Johns Hopkins Medicine.Fetal heart monitoring.
MedlinePlus.Nonstress test.
Sholapurkar SL.Categorization of fetal heart rate decelerations in American and European practice: importance and imperative of avoiding framing and confirmation biases.J Clin Med Res. 2015;7(9):672-680. doi:10.14740/jocmr2166w
Oxford Academic Health Science Network Maternity.Oxford AHSN Cardiotocograph (CTG) Interpretation Tool Definitions.
Chuai F, Dong T, Liu Y, et al.The effect of intrapartum prolonged oxygen exposure on fetal metabolic status: Secondary analysis from a randomized controlled trial.Front Endocrinol (Lausanne). 2023;14:1204956. doi:10.3389/fendo.2023.1204956
American Pregnancy Association.Early fetal development.
Gravett C, Eckert LO, Gravett MG, et al.Non-reassuring fetal status: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data.Vaccine. 2016;34(49):6084-6092. doi:10.1016/j.vaccine.2016.03.043
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