2. “FETAL HEART MONITORING”
Dr Seyed Asadollah Kalantari
OB & Gynecologist
Isfahan Fertility & Infertility Center

3. FETAL MONITORING
Non Stress Tests
Contraction Stress Tests

4. Non stress test

5. Non stress test
A nonstress test determines the response of the fetal heart rate to fetal movements.
“running a strip.” During a nonstress test, an external monitor is placed around the mother's abdomen to record the fetal heart rate.
Each time ,the fetal movement is noted on the recording chart.
If the fetus is asleep, the mother press on her abdomen or make a loud noise to awake the fetus.

6. Cont OB/GYN 2005;50:38-48

7. Cont OB/GYN 2005;50:38-48

8. Non stress test
The NST is derived from observations that a fetus that is not acidotic and has an intact normally functioning autonomic nervous system will have periodic accelerations of the FHR.

9. Non-stress test physiology
Afferent signals:
Baroreceptors: aorta, atrium, carotids
Proprioceptors: joints
Pain fibers: skin
When stimulated, send afferent impulses to brain to increase FHR
Efferent signals increase FHR
If movement and accelerations observed, reasonable to conclude the afferent and efferent limbs intact and cardioregulatory neurons adequately oxygenated

10. Indications for the NST
Suspected post-maturity
Maternal diabetes
Maternal hypertension: chronic and pregnancy-related disorders
Suspected or documented IUGR
History of previous stillbirth
Isoimmunization

11. Indications for the NST
Older gravida
Decreasing fetal movement
Sever maternal anemia
Multiple gestation
High-risk antepartal conditions: PROM, PTL, bleeding
Chronic renal diseases

12. Factors that can interfere with NST
Fetal positions
Being unable to lie still throughout the procedure
Being overweight
An infection in either you or your baby.
Low (hypoglycemia) or high (hyperglycemia) blood sugar levels.
Medications, such as magnesium sulfate.
Alcohol.
Illegal drugs, such as cocaine.
stool (feces) or air in the intestines or rectum interfering with the fetal ultrasound

13. NST: How to do it Patient in lateral tilt position
Tracing observed for 40 minutes
Accelerations peak (but do not necessarily remain) at least 15 BPM above baseline
Last for 15 seconds
Reactive: 2 or more accelerations within 20 m period
Nonreactive: one that lacks sufficient accelerations over 40 minute period
No contraindications

14. The preterm fetus Frequently nonreactive 24-28 weeks,
up to 50% of NST nonreactive
28-32 weeks,
15% nonreactive

15. Reactive NST (Acceleration)

16. Non Reactive NST (Lack of Acceleration )
Fetal sleep
Medication
Hypoxia

18. Contraction stress test
(CST) measures the fetus''s ability to tolerate the stress of uterine contractions started (induced) before true labor begins.
during a contraction stress test ,evaluate the fetus''s heart rate during contractions.
helps evaluate the placenta''s ability to provide enough oxygen to the fetus.
For determine the safest method of delivery.
A contraction stress test is also called an oxytocin challenge test.

19. Contraction stress test
the hormone oxytocin is given to cause labor contractions.
you may massage your nipples to prompt your body to release oxytocin.
(decelerates) instead of (accelerates) after a contraction, baby not be able to tolerate the stress of normal labor.
A contraction stress test is often done if a baby''s heart rate is abnormal during (nonstress test).
This test may be used in rare cases for women who have had an abnormal nonstress test or biophysical profile

20. Interpreted as to the presence or absence of late decelerations
CST interpretation
Interpreted as to the presence or absence of late decelerations
Negative: no late or significant variable decelerations
Positive: Late decels following 50% or more of contractions
Equivocal: intermittent late decels or significant variable decels
Equivocal-hyperstimulatory: FHR decels in presence of contractions occurring more than every 2 minutes or lasting longer than 90 seconds
Unsatisfactory: fewer than 3 contractions in ten minutes

21. Contraction stress test
Contraindications:
Preterm labor patients at high risk of preterm labor
PROM
History of extensive uterine surgery or classical cesarean
Known placenta previa

22. Positive contraction stress test
Fetal heart rate decceleration
Fetal hypoxia (uteroplacental insufficiency)

23. Negative contraction stress test
Fetal heart rate decceleration

24. FHR Variability
Increased Variability: marked variability from a previous average variability.
Causes: early mild hypoxia
- fetal stimulation
- uterine palpation
- contractions
- fetal activity
- maternal activity
- illicit drugs
Illicit drugs: specifically cocaine and methanphetamines.
Non-reassuring patterns: include decreasing variability and late decelerations.

25. Saltatory ( Increased Variability) pattern with wide variability
Saltatory ( Increased Variability) pattern with wide variability. The oscillations of the fetal heart rate above and below the baseline exceed 25 bpm.

26. FHR Variability
Decreased Variability: marked decrease in variability from a previous average variability.
Causes: hypoxia / acidosis; CNS depressants; analgesics / narcotics; barbiturates; tranquilizers, anaractics; parasympatholytics; general anesthetics; prematurity (<24 wks); fetal sleep cycles; congenital abnormalities; fetal cardiac dysrhythmias.

27. FHR Variability Decreased Variability (continued):
Significance: benign when associated with fetal sleep cycles; if drugs, variability usually increases as drugs are excreted; when associated with uncorrectable late decelerations indicates presence of fetal acidosis and can result in low APGARs.
Nsg.Interventions: none, if fetal sleep cycle, or CNS depressants; consider fetal scalp stimulation or apply a spiral electrode; monitor fetal oxygen saturation; prepare for birth if indicated.

28. Selected High-Risk Indications for Continuous Monitoring of Fetal Heart Rate
Maternal medical illness - Gestational diabetes - Hypertension - Asthma
Obstetric complications - Multiple gestation - Post-date gestation - Previous cesarean section - Intrauterine growth restriction - Premature rupture of the membranes - Congenital malformations - Third-trimester bleeding - Oxytocin induction/augmentation of labor - Preeclampsia
Psychosocial risk factors - No prenatal care - Tobacco use and drug abuse

30. Factors that can interfere with Electronic fetal monitoring
Nicotine or caffeine which can falsely raise your baby's heart rate and produce inaccurate test results.
Extra noises such as your heartbeat or your stomach rumbling.
baby is sleeping during a nonstress test.
Fetal movement during the test. If your baby is moving a lot, it may be difficult to correctly position the external montioring device.
Being overweight, or pregnant with multiple babies. In these cases it may be difficult to correctly position the external monitoring device.

31. INDICATION Electronic fetal monitoring
diabetes
high Blood Pressure
small baby or baby not growing properly
past your due date
too much or too little fluid around the baby

32. Baseline fetal heart rate is 130 to 140 beats per minute (bpm), preserved beat-to-beat and long-term variability. Accelerations last for 15 or more seconds above baseline and peak at 15 or more bpm. (Small square=10 seconds; large square=one minute)

33. Increase the baseline fetal heart
Prematurity
maternal anxiety
fever rate
Decreases the baseline fetal heart
fetal maturity

34. Periodic FHR Changes Accelerations Early Decelerations
Late Decelerations
Variable Decelerations
Sinusoidal Pattern

35. Accelerations fetal movement. Partial umbilical cord compression
This occurs with normal autonomic function, which acts to preserve cardiac output by increasing heart rate in response to decreased blood return to the fetal heart.

36. Decelerations
50% of NST
Non repetitive and less than 30 seconds in duration, obstetric intervention is not needed
repetitive decelerations or decelerations that last longer than 60 seconds are associated with an increased risk of fetal demise and cesarean delivery for the diagnosis of nonreassuring FHR pattern

37. Early Decelerations
Definition: a transitory gradual decrease and return to baseline FHR in response to fetal head compression.
Generally starts before the peak of the uterine contractions.
Returns to the baseline at the same time as the contraction returns to its baseline.
Considered benign. No interventions.
DECELERATIONS:
Caused by dominance of parasympathetic response.
May be benign or nonreassuring.
Described by their visual relationship to the onset and end of a contraction and by their shape.
Other CAUSES:
During contractions
During vaginal examinations
As a result of fundal pressure
During placement of the internal mode of fetal monitoring
Usually occur during the first stage of labor when the cervix is dilated 4-7 cm.
Sometimes seen during the second stage when the woman is pushing.
Generally “U” shaped.

38. Early deceleration in a patient with an unremarkable course of labor
Early deceleration in a patient with an unremarkable course of labor. Notice that the onset and the return of the deceleration coincide with the start and the end of the contraction, giving the characteristic mirror image.

39. Late deceleration with loss of variability
Late deceleration with loss of variability. This is an ominous pattern, and immediate delivery is indicated.

40. Nonreassuring pattern of late decelerations with preserved beat-to-beat variability. Note the onset at the peak of the uterine contractions and the return to baseline after the contraction has ended. The second uterine contraction is associated with a shallow and subtle late deceleration.

41. Late Decelerations
Definition: a transitory gradual decrease in and return to baseline of FHR associated with contractions.
Begins after the contraction has started, and the lowest part of the decel occurs after the peak of the contraction.
Usually does NOT return to baseline until after the contraction is over.
Indicates uteroplacental insufficiency. Interventions required!
Considered ominous sign when they’re uncorrectable, especially when associated with decreased variability and tachycardia.
LATE DECELS:
Usually indicate the presence of fetal hypoxemia stemming from insufficient placental perfusion.
Associated with fetal hypoxemia progressing to hypoxia and acidemia progressing to acidosis.
Nponreassuring pattern is associated with fetal hypoxemia, acidemia, and low Apgar scores.
Generally repeatative.
Rarely decelerates <100 bpm. However, shallow decels have the same significance.
INTERVENTIONS:
Aimed at increasing uteroplacental perfusion.
Turn to left side; increase mainline IV; shut off pitocin; give O2.
CAUSES:
Uterine hyperactvity or hypertonicity
Maternal supine hypotension
Epidural or spinal anesthesia
Placenta previa
Abruptio placentae
Hypertensive disorders
Postmaturity
Intrauterine growth restriction
Diabetes mellitus
Intraamniotic infection

42. Late Decelerations Interventions: Change maternal position (lateral)
Correct maternal hypotension (elevate legs)
Increase rate of maintenance IV
D/C oxytocin if infusing
Administer O2 at 8-10 L/min (face mask)
Fetal scalp or acoustic stimulation
Assist with fetal O2 saturation if ordered
Assist with birth if pattern cannot be corrected.

43. Late deceleration with loss of variability
Late deceleration with loss of variability. This is an ominous pattern, and immediate delivery is indicated.

44. Late deceleration

45. Variable Decelerations
Definition: an abrupt decrease in FHR that is variable in duration, intensity,and timing related to onset of contractions; caused by umbilical cord compression.
Onset to the beginning of the nadir is <30 seconds; decrease in > 15 bpm, lating >15 seconds; variable times in contracting phase; often preceded by transitory acceleration.
Return to baseline is rapid and <2 min from onset; sometimes with transitory acceleration immediately before and after decel.
Described as: mild, moderate, or severe.
VARIABLES:
“V”, “U” or “W” shaped.
“shouldering” or “overshoot”.
Severe variables have a slow return to baseline.
Commonly observed late in labor with fetal descent and pushing.
MILD VARIABLES: decelerates to any level, <30 seconds with abrupt return to baseline.
MODERATE VARIABLES: decelerates to > 80 bpm, any duration, with abrupt return to baseline.
SEVERE VARIABLES: decelerates to <6 bpm for >60 seconds, with slow return to baseline.
CAUSES:
Maternal position with cord between fetus and maternal pelvis
Cord around fetal neck, arm, leg, or other body part
Short cord
Know in cord
Prolapsed cord
OCCURANCE:
In approx. 50% of all labors and usually are transient and correctable.
REASSURING variables: last <45 sec., normal baseline rate continues; variability does not decrease.
NONREASSURING variables: decreas in FHR to <70 bpm for >60 sec; have prolonged return to baseline; baseline rate increases; variability is absent.
Associated with fetal acidemia, hypoxemia, and low Apgar scores; severe variable decelerations with average baseline variability just before birth are usually well tolerated.

46. Variable Decelerations
Interventions:
Change maternal position (side to side).
If severe:
D/C oxytocin if infusing
Administer O2 at 8-10 L/min (face mask)
Assist with vag or speculum exam
If cord is prolapsed, examiner will elevate fetal presenting part with cord between gloved fingers until c/s is accomplished
Assist with amnioinfusion if ordered
Assist with fetal O2 saturation monitoring if ordered
Assist with fetal O2 saturation if ordered
If pattern cannot be corrected, assist with birth (vaginal assisted or cesarean).

47. Variable deceleration with pre- and post-accelerations ("shoulders")
Variable deceleration with pre- and post-accelerations ("shoulders"). Fetal heart rate is 150 to 160 beats per minute, and beat-to-beat variability is preserved.

48. Severe variable deceleration with overshoot
Severe variable deceleration with overshoot. However, variability is preserved

49. Prolonged Decelerations
Definition: a visually apparent decrease in FHR below the baseline 15 bpm or more and lasting more than 2 minutes but less than 10 minutes.
Benign causes: pelvic exam, application of spiral electrode, rapid fetal descent & sustained maternal valsalva maneuver.
Other causes (severe): progressive severe variable decels, sudden umbilical cord prolapse, hypotension, paracervical anesthesia, tetanic contraction & maternal hypoxia (may occur with seizure).
A deceleration lasting more than 10 minutes is considered a baseline change.
Hypotension: may be caused by Spinal or Epidural analgesia or anesthesia

50. Signs of Nonreassuring Variable Decelerations that Indicate Hypoxemia
Increased severity of the deceleration
Late onset and gradual return phase
Loss of "shoulders" on FHR recording
A blunt acceleration or "overshoot" after severe deceleration
Unexplained tachycardia
Saltatory variability
Late decelerations or late return to baseline
Decreased variability

51. Interference Hypoxemia Acidemia oligohydramnios
interfere with measures of central
nervous system (CNS) performance,
such as
FHR patterns
Fetal movement
Tone

52. Other DEFINITIONS
Tachycardia: a baseline FHR >160 bpm for a duration of 10 minutes or longer.
Bradycardia: a baseline FHR <110 bpm for a duration of 10 minutes or longer.
Tachycardia:
Considered a sign of early hypoxemia (especially when associated with late decelerations and minimal or absent variability).
Can result from maternal or fetal infection (prolonged rupture of membranes with amnionitis); maternal hyperthyroidism or fetal anemia; or in response to drugs such as atropine, hydroxyzine (vistaril), terbutaline, or illicit drugs such as cocaine or methamphetamines.
BRADYCARDIA:
Must be distinguished from prolonged deceleration patterns.
Can be considered a later sign of fetal hypoxia and is known to occur before fetal death.
Can result from placental transfer of drugs; compression of the umbilical cord; maternal hypothermia, maternal hypotension.
Maternal supine hypotension syndrome – caused by the weight and pressure of the gravid uterus on the vena cave, decreases the return of blood flow to the maternal heart, which then reduces maternal cardiac output and blood pressure.

53. Fetal Monitoring Bradycardia Fetal heart rate less than 120 bpm
If longer than 5 minutes, consider delivery
Can tolerate 80-90's for about 20 minutes
Can tolerate 60-70's for only about 6-10 minutes
Common etiologies:
Maternal hypotension
Maternal hypoxia
Hypothermia
Placental abruption
Uterine tetany

54. Bradycardia
Baroreceptors influence the FHR through the vagus nerve in response to change in fetal blood pressure
Hypoxia
uterine contractions
fetal head compression
fetal grunting

55. Causes of Severe Fetal Bradycardia
Prolonged cord
compression Cord
prolapse Tetanic
uterine contractions
Paracervical block
Epidural and spinal anesthesia
Maternal seizures
Rapid descent
Vigorous vaginal examination

56. Tachycardia
Chemoreceptors located in the aortic and carotid bodies respond to hypoxia, excess carbon dioxide and acidosis, producing tachycardia and hypertension.

57. Fetal Monitoring Tachycardia Fetal heart rate greater than 160 bpm
Usually tolerated well
Common etiologies:
maternal fever
chorioamnionitis
Beta-agonists

58. Fetal tachycardia with possible onset of decreased variability (right) during the second stage of labor. Fetal heart rate is 170 to 180 bpm. Mild variable decelerations are present.

59. Fetal Monitoring Sinusoidal Pattern
Fetal heart rate exhibits a sinusoidal wave form
Common etiologies :
Fetal anemia
Fetal hypoxia
Breech presentation

60. True sinusoidal pattern Note the decreased regularity
and the preserved beat-to-beat variability,

61. Pseudosinusoidal pattern
Note the decreased regularity and the preserved beat-to-beat variability

62. “ THE END “