Intrapartal Fetal Surveillance Flashcards
Normal fetal heart rate is ?
120- 160
Tachycardia and bradi if it persists for more than 10 min
In pinard maneuver
high risk
Every 15 min in 1st stage
Every 5 min in 2nd stage
In low risk
Every 30 min in 1st stage
Every 15 min in 2nd stage
Fetal heart rate pattern of EFM
Base line heart rate
Base line FHR variability (beat to beat variability)
Periodic or episodic changes
Presence of decelerations
Presence of accelerations
Changes or trends of FHR patterns over time
Bradycardia classification
mild 100-119bpm
moderate 80-100bpm
severe<80bpm
Severe tachycardia
Above 180
Beat to beat variability tells
Hypoxia
If intact it shows good cns function and cardiac function
Beat to beat variability
Minimal less than 5
Moderate 6-25
Marked above 25
Early deceleration
; Begin early in contractions With peak contraction
Return to baseline by the time contraction is over
; Not; 30-40 bpm below base line
; Ushaped ; onset and return is gradual
; Caused by compression of fetal head by the uterine cervix (4-6cm cervical dilation)
¡ Not associated with fetal hypoxia, acidemia or low APGAR scores
¡ Uncommon(5-10% all fetus)
¡
Late deceleration
Onset 30 sec after onset of contraction (at or after peak)and their nadir is after the peak of contraction
are also U shaped
Not associated with accelerations
Rarely descend more than 30-40bpm below baseline rate ,typically 10-20bpm.
Causes of late decelerations include any factor that can alter delivery, exchange, or uptake of oxygen at the fetal-maternal interface within the placenta. That is the cause is secondary to U-P insufficency; Includes:
Excessive Ux contraction (oxytocin)
Maternal hypotension (epidural )
Micro vascular diseases of the placenta (post matures, HDP.DM, collagen vascular disease)
abruption
Severe maternal anemia or hypoxemia
Chronic fetal anemia
Variable deceleration
Abrupt and sharp decrease in FHR below the base line and return and onset, depth and duration have no relation with contractions.
Most common type of deceleration seen in labor
Are usually associated with accelerations (preceding/following)
Majority caused by cord compression/occlusion
Causes
Oligohydraminos
Nuchal cord/cord stretching
Cord prolapse, cord presentation/ compression
Abnormalities of cord – true knot, short cord,
Sometimes - hypoxia
Prolonged deceleration
Isolated decrease in FHR below the baseline ≥15bpm, lasting 2 to 10 from the onset to return to baseline.
May be caused by any of the mechanisms mentioned above, but are of a profound and sustained nature.
Acceleration
Is a visually apparent abrupt increase in FHR above the base line.
Short duration (30-90 sec)
Amplitude ≥15bpm above the base line and acceleration lasts ≥15sec
Before 32wk of GA >10bpm, ≥10sec
are physiologic response to fetal movement except those associated with variable deceleration
Presence of acceleration (Spontaneous /stimulation) is reassuring
Its presence in a NRFHRP rules out acidosis
Its absence in NRFHRP – 50% acidosis
But absence without NRFHR – not indicative of hypoxia
Meconium stainning
Hypoxic insult – vagal response – meconium passage
Can occur in absence of significant or sustained hypoxia
Mechonium staining is not indicative of fetal jeopardy on its own. It augments the diagnosis of fetal jeopardy in conjunction with a non-reassuring fetal heart rate pattern.
In this instance a thick mechonium staining is more significant in the diagnosis of fetal jeopardy than a lightly stained liquor.
Mechonium staining that appears for the first time in labor is also a significant indicator of fetal jeopardy
Mgt:
In face of reassuring FHR – expectant management
In relatively NRFHR – expectant not recommended
Should alert for : Oligohydraminos, Placental insufficiency , Umbilical cord compression, MAS
