• Contractions are essential for the progression of labour. However, excessive uterine activity is the most frequent cause of fetal hypoxia/acidosis. It can be detected by documenting tachysystole in the CTG tracing. There is software and equipment that is used to monitor multiple mothers and send the most precise alerts when in need of a special intervention.

Uterine Contractions

&nbsp A uterine contraction is a muscle contraction of the uterine smooth muscle.

&nbsp Since uterine contractions are always present in a thriving uterus, they are differentiated on the basis of frequency, amplitude, duration, and direction of propagation. Although there have been recent advances in knowledge regarding uterine contractions, there still remains a huge gap in understanding the related physiology at the cellular and molecular levels. Knowledge of the process of uterine contractions that eventually leads to the expulsion of the baby will help clinicians identify abnormalities that may lead to obstetrical complications, such as preterm labor and arrest of labor. This will also aid the pharmacists in developing and improving the drugs used for labor augmentation, induction, and tocolysis. Uterine contractions also play an essential role in minimizing postpartum bleeding, which explains why many drugs used to treat this complication target the pathway involved in myometrial contractility.

The primary function of uterine contractions is to expel the fetus from the uterine cavity. However, contractions also play an essential role in minimizing postpartum hemorrhage. Knowing the normal physiology of uterine contractions also allows clinicians to better differentiate between the true onset of labor and prodromal labor, also known as Braxton Hicks contractions. Braxton Hicks contractions occur sporadically and do not increase in strength. They are irregular in duration, frequency, and intensity, are unpredictable and non-rhythmic and are more uncomfortable than painful. True labor consists of contractions at regular intervals. As labor progresses, these contractions become stronger, and the time between each contraction decreases. The first stage of labor is divided into two phases, which are defined by the degree of cervical dilation. The latent phase is during the dilation from 0 to 6 cm, while the active phase starts from 6 cm to full cervical dilation of 10 cm. The second stage of labor starts with cervical dilation of 10cm and ends with the delivery of the baby. The third stage of labor starts when the fetus is delivered and ends with the delivery of the placenta.

&nbsp The number of contractions present in a 10-minute window, averaged over 30 minutes, is the manner by which uterine contractions are quantified.
Contraction frequency is a partial assessment of uterine activity.
Other factors such as duration, intensity, and relaxation time between contractions are equally important in clinical practice.
The terminology used to describe uterine activity is listed below:

Normal: five contractions or less in 10 minutes, averaged over a 30-minute window;

Tachysystole: more than five contractions in 10 minutes, average over in a 30-minute window.

Characteristics of uterine contractions :

The terms hyperstimulation and hypercontractility are not defined and should be abandoned.
Tachysystole should always be qualified as the presence or absence of associated FHR decelerations.
The term tachysystole applies to both spontaneous and stimulated labor. The clinical response to tachysystole may differ depending on whether contractions are spontaneous or stimulated.

excessive uterina contractions

Excessive uterine contractions

&nbsp &nbsp Contractions are essential for the progression of labour, but they compress the vessels running inside
the myometrium and may transiently decrease placental perfusion and/or cause umbilical cord
compression . With the tocodynamometer, only the frequency of contractions can be
reliably evaluated, but increased intensity and duration can also contribute to FHR changes.
Tachysystole – represents an excessive frequency of contractions and is defined as the
occurrence of more than 5 contractions in 10 minutes, in two successive 10-minute periods, or
averaged over a 30-minute period.

&nbsp &nbsp Contractions compress the maternal blood vessels running inside the myometrium,
decreasing placental perfusion , and this can result in a temporary reduction of maternalfetal gas exchange.
If during contractions the umbilical cord is compressed between fetal parts,
or between fetal parts and the uterine wall, this will result in interference with blood
circulation. The frequency, duration and intensity of uterine contractions are key determinants
of the magnitude and effects of these disturbances. The interval between contractions is of
particular importance for re-establishment of fetal oxygenation. There are data to suggest that
in spontaneous labour it takes up to 90 seconds after a contraction for fetal oxygenation to be
restored , while in oxytocin-augmented labours this recovery period averages 138 seconds.
Excessive uterine activity is often responsible for
decreased fetal oxygenation, and where possible, should be avoided irrespective of FHR.

&nbsp Excessive uterine activity is the most frequent cause of fetal hypoxia/acidosis and it can be detected by documenting tachysystole in the CTG tracing and/or palpating the
uterine fundus. It can usually be reversed by reducing or stopping oxytocin infusion, removing
administered prostaglandins if possible, and/or starting acute tocolysis with beta-adrenegic
agonists (salbutamol, terbutaline, ritodrine) , atosiban , or nitroglycerine . During the second
stage of labour, maternal pushing efforts can also contribute to fetal hypoxia/acidosis and the
mother can be asked to stop pushing until the situation is reversed.

&nbspRepetitive decelerations are frequent during the second stage of labor and may
occur as a result of aorto-caval, umbilical cord or fetal head compression. Changing the
maternal position may revert the first two causes. However, if decelerations start more
than 20 seconds after the onset of a contraction and take more than 30 seconds to
recover to baseline values (late decelerations), or when decelerations last more than 3
minutes (prolonged decelerations), this is very suggestive of fetal hypoxia/acidosis. If an
accompanying tachysystole is detected, consideration should be given to acute tocolysis
with beta-adrenegic agonists (salbutamol, terbutaline, ritodrine), atosiban, or
nitroglycerine , followed by continued auscultation to document the
normalization of the pattern. Sudden maternal hypotension rarely happens during labour
in the absence of conduction analgesia, but should it occur in association with a fetal
deceleration, increased intravenous fluid administration turning the mother to her side
and administering intravenous ephedrine will usually revert the situation. When late
and/or prolonged decelerations are documented during the second stage of labour the
mother should be asked to stop pushing until this pattern disappears. If there is no rapid
reversal of late and/or prolonged decelerations, consideration should be given to
immediate delivery, by cesarean section or instrumental vaginal delivery, according to
obstetric conditions and local resources

&nbspTo reduce the occurrence of fetal complications during pregnancy and
labour, timely and valid recognition of fetal distress is needed to intervene promptly
and appropriately. By doing so, fetal metabolic acidosis, which is associated with severe
perinatal morbidity and mortality can be reduced. In addition, unnecessary medical
interventions, which are associated with increased neonatal and maternal morbidity and
mortality, can also be abated. This is of great importance during the preterm period, since
unnecessary interventions in premature fetuses result in iatrogenic preterm births, while
preterm birth is the most frequent cause of infant death4. However, the timing of medical
intervention is extremely difficult since the current methods of fetal monitoring have
limited diagnostic value in detecting fetal distress. Therefore, improved monitoring of
fetal condition during pregnancy and labour is of major importance.

Fetal autonomic response to uterine contractions
Barcroft first described the development of cardiovascular reflexes during umbilical
cord occlusion in the fetus. His studies led to the description of early, variable and
late decelerations in human fetal heart rate. Autonomic modulation, during these three
types of decelerations, is briefly discussed in the next paragraphs.

Variable decelerations occur due to umbilical cord compression. Studies showed that
in healthy fetal lambs, a fetal heart rate response to uterine contractions occurred only
after the umbilical blood flow was reduced by at least 50%. During short partial cord
occlusion, no significant changes in fetal arterial pH or blood pressure occur and the
resulting hypoxaemia leads to a variable deceleration in fetal heart rate. This variable
deceleration was abolished during parasympathetic blockade with atropine and is thus of
chemoreceptor reflex origin and vagally mediated. The deceleration during hypoxaemia
is an important fetal adaptation mechanism that is believed to reduce myocardial work
and oxygen requirement. The changes in fetal heart rate vary with the magnitude
of reduction in umbilical blood flow. Complete cord occlusion is accompanied by
hypoxaemia and increased blood pressure and leads to prolonged variable deceleration
of fetal heart rate that is the result of both chemoreceptor and baroreceptor activation.
The increase in blood pressure during complete cord occlusion is due to increased
peripheral resistance. This increased peripheral resistance is due to both occlusion of
the umbilical cord and sympathetically mediated peripheral vasoconstriction caused by
hypoxaemia. During prolonged or frequent cord occlusion, the fetus has no time to
recover from hypoxaemia. The fetal heart rate decreases during the occlusion and rises
to above normal values after the occlusion (overshoot), this overshoot is probably due to
decreased vagal and increased β-adrenergic tone as it occurs in the face of fetal acidosis
or hypotension. If hypoxia is severe and prolonged for at least three minutes,
the initial vagal bradycardia is sustained by direct hypoxic myocardial depression39.
In conclusion, the fetal heart rate responses to cord compression are dependent on the
severity of reduction in umbilical blood flow and on the frequency and duration of cord
compression. The chemo- and baroreceptor reflex are thus not only a component of fetal
adaptation but are also an indicator of the presence of fetal hypoxaemia. The depth to
which fetal heart rate falls is often related to the severity of the hypoxia39. In other words,
shallow decelerations indicate a modest reduction in uteroplacental blood flow, and deep
decelerations indicate severe reduction. Thus, a shallow deceleration in labour indicates
a mild fall in fetal oxygen tension. Deep decelerations reflect profound, albeit transient,
hypoxaemia. Whether the repeated hypoxia that is associated with decelerations in heart
rate is benign depends on the fetal condition and placental reserve, and on the duration
and frequency of the decelerations.
Late decelerations

In case of reduced fetal reserve, a reduction in oxygen supply due to reduced placental
blood flow during a contraction may also cause the activation of chemoreceptors. This
activation of chemoreceptors evokes a vagal and a sympathetic response. The direct
vagal response yields a cardiodecelerator effect. The direct sympathetic response leads to
a β-receptor mediated cardioaccelerator effect and to increased cardiac contractility. This
β-receptor response increases blood pressure. In addition, the sympathetic pathway leads
to an α-receptor mediated increase in vascular resistance which also increases blood
pressure. The increase in blood pressure is sensed by the baroreceptor that reacts with an
increased afferent fire rate that is forwarded to both the sympathetic centre (inhibition)
and the vagal centre (stimulation). The vagal centre responds with a cardiodecelerator
effect. The net effect is a deceleration in heart rate that starts after the contraction has
reached its peak. This baroreceptor reflex activation is due to an increase in blood
pressure as part of the cardiovascular adaptation to hypoxia. After the contraction, the
sympathetic activation is maintained, causing tachycardia.
Early decelerations

The fetus also reacts to changes in its external environment. For example, fetal head
compression during uterine contractions increases intracranial pressure and cerebral
resistance, thus reducing cerebral perfusion and oxygen supply. This local hypoxaemia
stimulates the vagus nerve and decreases fetal heart rate. Once the contraction
diminishes, cerebral flow will restore and the oxygen level in the blood will normalise.
This will also restore vagal nerve fire rate and fetal heart rate will correspondingly return
to baseline level. This cascade is seen on the cardiotocogram as early decelerations43.
During the last phase of labour, this cascade can also cause marked vagally induced

Chronic partial hypoxia leading to acidosis develops over a period of hours rather than
minutes. While most babies benefit from the normal intermittent relative hypoxia of labour
associated with uterine contractions, chronic hypoxia followed by acidosis may develop in
some, for example, as a result of long labours, where there is repeated cord compression
with contractions, or where there are excessive uterine contractions (either spontaneous or
stimulated). In these cases, a more gradual change occurs in the characteristics of fetal heart

excessive uterina contractions

Hypoxemia ( hypo- +‎ ox- +‎ -emia )


(anatomy) Below; beneath; under.
Synonym: sub- (Latinate)
(medicine) Deficient; less than normal.
Synonym: sub- (Latinate)


-emia f

(pathology) -aemia (forms the names of conditions affecting the blood or the bloodstream)

excessive uterina contractions

Hypoxia ( hypo- +‎ ox +‎ -ia )


(anatomy) Below; beneath; under.
Synonym: sub- (Latinate)
(medicine) Deficient; less than normal.
Synonym: sub- (Latinate)




Used in forming plurals of nouns in -ium and -ion.

excessive uterina contractions

Tachysystole ( tachy- +‎ systole )



systole (plural systoles)

(physiology) The rhythmic contraction of the heart, by which blood is driven through the arteries.

excessive uterina contractions

Tocolysis ( toco- +‎ -lysis )


Relating to childbirth.


decomposition or breakdown

excessive uterina contractions


Cardiotocography (CTG), known as Electronic Fetal Monitoring, is typically performed at
third trimester during pregnancy and in labour to primarily monitor the relationship between fetal
heart rate (FHR) and contractions of the uterus (UC). CTG outcomes allow experts to determine
the health of the foetus and to detect any fetal impairments.

Cardiotocography (CTG) is a monitoring of fetal heart rate and uterine contractions. Since 1960 it is routinely used by obstetricians to assess fetal well-being. Many attempts to introduce methods of automatic signal processing and evaluation have appeared during the last 20 years, however still no significant progress similar to that in the domain of adult heart rate variability, where open access databases are available (e.g. MIT-BIH), is visible. Based on a thorough review of the relevant publications, presented in this paper, the shortcomings of the current state are obvious. A lack of common ground for clinicians and technicians in the field hinders clinically usable progress. Our open access database of digital intrapartum cardiotocographic recordings aims to change that.

&nbsp Surveillance for fetal hypoxia in labour is undertaken by fetal heart rate monitoring either by
intermittent auscultation or by a continuous recording by a cardiotocograph. The aim of using
a cardiotocograph is to provide a visual continuous record of fetal heart rate and uterine
contractions. There are features that can indicate the baby is well and responding normally to
the events of labour (for example, slowing of the fetal heart rate during a contraction). There
are other features that may indicate a serious emergency (for example, development of a
persistent bradycardia following cord prolapse or placental abruption).

Detection of fetal distress during labour is complex. The cardiotocogram (CTG), a
simultaneous recording of fetal heart rate and uterine contractions, is the method used
worldwide for fetal surveillance. Poor specificity of this method has resulted in increased
rates of operative deliveries without a decrease in perinatal mortality or cerebral palsy.
It has been shown that during labour combined use of CTG and automatic ST-waveform
analysis of the fetal electrocardiogram (ECG; STAN®, Neoventa Medical, Moelndal,
Sweden) reduces the rates of severe metabolic acidosis at birth and instrumental
vaginal delivery for fetal distress. However, slow progressive deterioration of the
CTG without pathological changes in ST-waveform (ST-events) has been reported as
a cause of neonatal metabolic acidosis despite monitoring using STAN®. Furthermore,
STAN® remains dependent on the assessment of the CTG, which has a high inter- and
intraobserver variability. Although the CTG has a high sensitivity, ST-events occur at a
similar frequency for normal and abnormal CTG patterns. This illustrates the need for
more detailed information on the fetal cardiovascular response to hypoxaemia.

&nbspCTG records only 2 parameters: the fetal heart rate and uterine contractions. The continuous
monitoring allows a number of features to be considered simultaneously which can also be
examined for trends over a period of time. In contrast, intermittent auscultation is used to
record the fetal heart rate over a period of 1 minute immediately after a contraction once
every 15 minutes during the first stage of labour, and after every contraction in the second
stage. It can be used to detect decelerations that occur during that minute but it does not
identify decelerations at other times or baseline variability. For this reason, CTG is used
when there are factors present that indicate an increased risk of developing fetal hypoxia,
including abnormalities detected using intermittent auscultation.

CTG, which records (-graph) the fetal heart rate (cardio-) and the uterine contractions (-toco),
is used as the ultrasound waves-based diagnostic monitor to evaluate the well-being of fetuses
and to depict fetal distress such as foetal hypoxia or foetal tachycardia (Almström et al., 1992).

CTG measures foetal heart rate (FHR) and the pressure inside the uterus antenatally and the
intrapartum (Spencer, 1993).

Foetal heart rates that are not within a baseline of 110-160 Beats
Per Minute (BPM) can lead to invasive investigations or, in critical cases, to an emergency
caesarean section or instrumental vaginal birth as babies are short of oxygen (Grivell et al.,
2015). Foetuses with foetal heart rate variability greater than 6 BPM and accelerations with
foetal movement (FM) developed a foetal well-being, whereas foetuses who do not meet this
criterion died in the perinatal period (Parer and King, 2000). Clinicians’ misinterpretations of
CTG recordings led to an increase of obstetric litigations (Williams and Arulkumaran, 2004).

excessive uterine contractions Edan f15 vision

Omniview-SisPorto® – Central Monitoring and Real time alerts system

&nbsp The Omniview-SisPorto® system acts as a central monitoring station, allowing the combined display of up to 25 CTG and/or STAN tracings on the same computer screen. The SisPorto computerized analysis of the CTG features and ST events provides additional safety for fetal surveillance. Several automated features are included to reduce staff handling needs to minimum.


Features at a glance

  • Tracing start and stop handled automatically by the program
  • Automatic optimization of active tracings size
  • Automatic tracing archival
  • Display of STAN events and T/QRS crosses
  • Automatic Name and ID communication with STAN 31
  • Visual and sound alerts for CTG features including for:
    • Excessive uterine contractions
    • Prolonged decelerations
    • Reduced long-term variability
    • Reduced short-term variability
  • Combination of ST events and non-reassuring CTG features
  • Stored tracing retrieval and printing
  • Stored tracing reviewing and simulation for education purposes
  • And much more…

Viewing of multiple tracings

Tracing acquisition, display and storage is handled automatically by the program, as it continuously detects the connection and disconnection of fetal monitors transmitting appropriate signal features.

The SisPorto analysis of the fetal heart rate provides real time alerts to aid intrapartum  management. Analysis includes estimation of uterine contractions, of fetal heart rate baseline, identification of accelerations, decelerations, and quantification of short- and long-term variability.

A detailed display can be accessed by maximizing a single tracing window with the possibility of reviewing the whole tracing.

A multiple client architecture ensures that a practically unlimited number of computers can be connected via a local intranet to display tracings. Tracings can be printed automatically on tracing end or at the user’s request, with or without the results of automated analysis.



The SisPorto analysis of the fetal heart rate provides real time alerts to aid intrapartum management and has shown to improve the accuracy of clinicians when analyzing CTGs.

Omniview-SisPorto® leads the technology in CTG analysis, with extensive publishing on reference journals and the involvement of top authors from the field.

Analysis includes estimation of uterine contractions, of fetal heart rate baseline, identification of accelerations, decelerations, and quantification of short- and long-term variability.


Visual and Sound Alerts

Suspicious alerts provide just visual messages. In this example they may help managing oxytocin use and suggest searching for reactivity signs.
Pathological alerts have also a sound alert and some are emergency cases like the one shown below.
At any time a user may open a window with more detail on the analysis. Both quantitative and Graphical results are available.

The graphical results contain the estimated baseline and the calculations for accelerations, decelerations and uterine contractions.


For additional information please send you queries to omniview@speculum.pt.

&nbspOmniview-SisPorto® CTG alerts provide help to the management of labour and timely detection of fetal suffer and making birth safer. This is sustained by extensive publishing on reference journals as: American Journal Obstetrics and Gynecology, AOG Scandinavia, Journal of Maternal-Fetal & Neonatal Medicine, and International Journal of Gynecology and Obstetrics. (…)

&nbspOmniview-SisPorto® provides central monitoring with a reliable and accurate Computerized Analysis of the CTG intrapartum analysis. It is a central fetal monitoring viewing system, developed at the School of Medicine of the University of Porto, in collaboration with the Institute of Biomedical Engineering and SPECULUM.

&nbspOmniview-SisPorto® technology, through an advanced fetal trace alerting system reduce the number of both false positive and false negative alerts, improving staff efficiency and birth safety.

&nbspOmniview-SisPorto® can be easily integrated with a sophisticated digital partograph. The MATERNUM allows to tailor its behaviour to each institution’s need, and provides custom complex calculations, reaction to imputed values and custom statistical report to be mailed automatically.

OmniView™ is a modern Central Monitoring System for the Maternity Department, providing Central Surveillance and Archiving of all antenatal and labour CTGs and STAN® Recordings.

OmniView also provides a platform for the optional SisPorto® CTG Interpretation Module and the Maternum Partogram, Labour and Delivery Module.

SisPorto® analysis of FHR and ST Events has been proven to provide higher accuracy in predicting neonatal acidemia

Modern Central Monitoring Station with flexible architecture for simple expansion.

Automatic display configuration of all live recordings, with connection of unlimited number of beds and unlimited number of viewing stations.

SisPorto® Computerized CTG Interpretation Software provides comprehensive analysis of the CTG, Antenatal and Intrapartum CTGs, giving timely colour coded CTG Alerts to the Obstetric Staff.

SisPorto® includes ST-Events in its analysis of the Fetal Heart Rate.

OmniView-SisPorto® is fully compatible with STAN®, which provides familiar display modes, combined CTG and ST analysis and two-way communication.

Maternum™ is a Labour & Delivery Module which fully integrates with OmniView-SisPorto® or can be used independently.

Maternum™ is net-based and compatible with any tablet for portable use anywhere with internet access..

Full electronic Partogram.

Partogram Module

OmniView Partogram Module

Comprehensive Labour & Delivery Statistics.

Labour & Delivery Statistics

OmniView™ – Central Surveillance & Archiving:

OmniView™ is a Central Monitoring Station which can connect all well known fetal monitors and STAN® to a central dsiplay monitor for surveillance of all ongoing antenatal and labour CTGs and STAN® Recordings. There is no limit to how many CTGs can be connected or viewed simultaneously and there is also no limit to how many computers which can be set up as viewing stations.

OmniView™ will automatically adjust the display size of each CTG to create the best display of all live recordings. Each CTG can be opened into a Single Bed view to review the entire recording in detail.

OmniView™ archives all CTG recordings centrally onto a hospital server and the CTGs can be retrieved from archive and reviewed on any of the viewing stations.

Live ongoing CTGs, as well as archived CTGs, can also be viewed and retrieved remotely from outside the hospital from anywhere with Internet access and access to the hospital server.

OmniView™ comes with a CTG playback programme designed for use in education and training and would normally be installed on a laptop computer. The Playback Software enables playback of any archived CTG or STAN recording at different speeds, and to start and stop the playback to review scenarios.

STAN® FECG ST-Analysis:
OmniView™ is fully compatible with STAN® and displays the CTG in the familiar STAN® colours and all Fetal ECG ST-Analysis data and Events, as on STAN®.

STAN® also accepts data from OmniView™ and the Patient Name and ID can be registered either on OmniView™ or on STAN®. Usually, the midwife would make all notes and register the patient on STAN®, which is then displayed on OmniView™.

SisPorto® – Computerized CTG Analysis:
SisPorto® is a Computerized CTG Interpretation Software for use with Antenatal and Intrapartum CTGs. It uses the OmniView Central Monitoring System as it’s platform and is available as an option with OmniView™, hence OmniView-SisPorto®.

SisPorto® takes STAN® Events into accounts in the anlysis of the CTG features.
Hence, a significant ST Event can cause a Pathological CTG Alert, which needs attention.

Below is an example of a Red Pathological Alert, triggered by an abnormal CTG (Tachycardia, Decelerations) and an ST Event, plus an Alert for Excessive Uterine Contractions.

SisPorto Alert with ST-Event

Below is another example of a Red Pathological Alert, triggered by Low Short Term Variability, plus an Alert for Excessive Uterine Contractions.

SisPorto Alert, Low Short Term Variability

Maternum™ – Partogram, Labour & Delivery Module:
Maternum™ is a Labour & Delivery Module, which can either be used as a Stand-Alone System or used as an integral part with OmniView-SisPorto®.

Maternum™ is net-based and works with any portable tablets anywhere with Internet access and access to the hospital server.

Maternum™ feature:
– A Chalkboard for room identification and registration of patients
– A Partogram for labour progression graphs and notes
– Risk Factors
– Newborn and Delivery Details
– Search and Auditing Log
– Active Directory Authentication
– Integrated with OmniView™ or Stand-Alone
– Windows / Mac / Tablet compatible

excessive uterina contractions

Contact details

For more information about this solution, please contact Hugo Ferreira

What is fetal heart monitoring?

Fetal heart rate monitoring measures the heart rate and rhythm of your baby (fetus). This lets your healthcare provider see how your baby is doing.

Your healthcare provider may do fetal heart monitoring during late pregnancy and labor. The average fetal heart rate is between 110 and 160 beats per minute. It can vary by 5 to 25 beats per minute. The fetal heart rate may change as your baby responds to conditions in your uterus. An abnormal fetal heart rate may mean that your baby is not getting enough oxygen or that there are other problems.

There are 2 ways to do fetal heart monitoring, external and internal:

External fetal heart monitoring

This method uses a device to listen to and record your baby’s heartbeat through your belly (abdomen). One type of monitor is a Doppler ultrasound device. It’s often used during prenatal visits to count the baby’s heart rate. It may also be used to check the fetal heart rate during labor. The healthcare provider may also check your baby’s heart rate continuously during labor and birth. To do this, the ultrasound probe (transducer) is fastened to your belly. It sends the sounds of your baby’s heart to a computer. The rate and pattern of your baby’s heart rate are shown on a screen and printed on paper.

Internal fetal heart monitoring

This method uses a thin wire (electrode) put on your baby’s scalp. The wire runs from the baby through your cervix. It is connected to the monitor. This method gives better readings because things like movement don’t affect it. But it can only be done if the fluid-filled sac that surrounds the baby during pregnancy (amniotic sac) has broken and the cervix is opened. Your provider may use internal monitoring when external monitoring is not giving a good reading. Or your provider may use this method to watch your baby more closely during labor.

During labor, your healthcare provider will watch your uterine contractions and your baby’s heart rate. Your provider will note how often you are having contractions and how long each lasts. Because the fetal heart rate and contractions are recorded at the same time, these results can be looked at together and compared.

Your provider may check the pressure inside your uterus while doing internal fetal heart monitoring. To do this, he or she will put a thin tube (catheter) through your cervix and into your uterus. The catheter will send uterine pressure readings to a monitor.

Why might I need fetal heart monitoring?

Fetal heart rate monitoring is especially helpful if you have a high-risk pregnancy. Your pregnancy is high risk if you have diabetes or high blood pressure. It is also high risk if your baby is not developing or growing as it should.

Fetal heart rate monitoring may be used to check how preterm labor medicines are affecting your baby. These are medicines are used to help keep labor from starting too early.

Fetal heart rate monitoring may be used in other tests, including:

  • Nonstress test. This measures the fetal heart rate as your baby moves.
  • Contraction stress test. This measures fetal heart rate along with uterine contractions. Contractions are started with medicine or other methods.
  • A biophysical profile (BPP). This test combines a nonstress test with ultrasound.

Things that may affect the fetal heart rate during labor:

  • Uterine contractions
  • Pain medicines or anesthesia given to you during labor
  • Tests done during labor
  • Pushing during the second stage of labor

Your healthcare provider may have other reasons to use fetal heart rate monitoring.

What are the risks of fetal heart monitoring?

Radiation is not used for this test. The transducer usually causes no discomfort.

You may find the elastic belts that hold the transducers in place slightly uncomfortable. These can be readjusted as needed.

You must lie still during some types of fetal heart rate monitoring. You may need to stay in bed during labor.

With internal monitoring, you may have some slight discomfort when the electrode is put in your uterus.

Risks of internal monitoring include infection and bruising of your baby’s scalp or other body part.

Note: You should not have internal fetal heart rate monitoring if you are HIV positive. This is because you may pass the infection on to your baby.

You may have other risks depending on your specific health condition. Be sure to talk with your provider about any concerns you have before the procedure.

Certain things may make the results of fetal heart rate monitoring less accurate. These include:

  • Obesity of the mother
  • Position of the baby or mother
  • Too much amniotic fluid (polyhydramnios)
  • Cervix is not dilated or the amniotic sac is not broken. Both of these need to happen to do internal monitoring

How do I get ready for fetal heart monitoring?

  • Your healthcare provider will explain the procedure to you. Ask him or her any questions you have about the procedure.
  • You may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if anything is not clear.
  • The consent form for fetal heart monitoring may be included as part of the general consent for labor and birth.
  • Tell your healthcare provider if you are sensitive to or are allergic to any medicines, latex, tape, or anesthesia.
  • If fetal heart rate monitoring is done along with another monitoring test, you may be asked to eat a meal before the test. This can help make your baby more active.
  • The amniotic sac must be broken and your cervix must be dilated several centimeters before the internal device can be put in place.
  • Follow any other instructions your provider gives you to get ready.

What happens during fetal heart monitoring?

You may have fetal heart rate monitoring in your healthcare provider’s office or as part of a hospital stay. The way the test is done may vary depending on your condition and your healthcare provider’s practices.

Generally, fetal heart rate monitoring follows this process:

External fetal heart monitoring

  1. Depending on the type of procedure, you may be asked to undress from the waist down. Or you may need to remove all of your clothes and wear a hospital gown.
  2. You will lie on your back on an exam table.
  3. The healthcare provider will put a clear gel on your abdomen.
  4. The provider will press the transducer against your skin. The provider will move it around until he or she finds the fetal heartbeat. You will be able to hear the sound of the fetal heart rate with Doppler or an electronic monitor.
  5. During labor, the provider may check the fetal heart rate at intervals or nonstop, based on your condition and the condition of your baby.
  6. For continuous electronic monitoring, the provider will connect the transducer to the monitor with a cable. A wide elastic belt will be put around you to hold the transducer in place.
  7. The provider will record the fetal heart rate. With continuous monitoring, the fetal heart pattern will be displayed on a computer screen and printed on paper.
  8. You may not be able to get out of bed with nonstop external fetal heart rate monitoring.
  9. Once the procedure is done, the provider will wipe off the gel.

Internal fetal heart monitoring

  1. You will be asked to remove your clothes and put on a hospital gown.
  2. You will lie on a labor bed. Your feet and legs will be supported as for a pelvic exam.
  3. Your healthcare provider will do a vaginal exam with a gloved hand to see how far you are dilated. This may be slightly uncomfortable.
  4. If the amniotic sac is still intact, your healthcare provider may break open the membranes with a tool. You will feel warm fluid coming out of your vagina.
  5. Your healthcare provider will feel the part of the baby at the cervical opening with gloved fingers. This is usually the baby’s head.
  6. The provider will put a thin tube (catheter) into your vagina. He or she will put a small wire at the end of the catheter on the baby’s scalp. He or she will gently turn it on the baby’s skin.
  7. The provider will remove the catheter and leave the wire in place on the baby’s scalp.
  8. The provider will connect the wire to a monitor cable. He or she will keep it in place with a band around your thigh.
  9. You may not be able to get out of bed with nonstop internal fetal heart rate monitoring.
  10. Once the baby is born, the provider will remove the wire.

What happens after fetal heart rate monitoring?

You do not need any special care after external fetal heart monitoring. You may go back to your normal diet and activity unless your healthcare provider tells you otherwise.

After internal fetal heart rate monitoring, your healthcare provider will check your baby’s scalp for infection, bruising, or a cut. The provider will clean the site with an antiseptic.

Your healthcare provider may give you other instructions, based on your situation.

Next steps

Before you agree to the test or the procedure make sure you know:

  • The name of the test or procedure
  • The reason you are having the test or procedure
  • What results to expect and what they mean
  • The risks and benefits of the test or procedure
  • What the possible side effects or complications are
  • When and where you are to have the test or procedure
  • Who will do the test or procedure and what that person’s qualifications are
  • What would happen if you did not have the test or procedure
  • Any alternative tests or procedures to think about
  • When and how will you get the results
  • Who to call after the test or procedure if you have questions or problems
  • How much will you have to pay for the test or procedure