Intermediate Fetal Monitoring

-approximate mean FHR rounded to increments of 5bp during a 10 min segment - duration must be at least 2 min. or the baseline for that period is indeterminate

baseline rate less than 110 bpm

baseline of greater than 160 bpm

fluctuations in baseline FHR that are irregular in amplitude and frequency

amplitude range undetectable

amplitude range > undetectable but <5/min

amplitude ranges 6-25 bpm

amplitude range greater than 25 bpm

visually apparent abrupt (<30 sec to peak) increase in FHR above baseline for less than 2 minutes -15bpmx15sec for 32 weeks and up -10bpmx10sec for less than 32 weeks

acceleration lasting longer than 2 minutes but less than 10 minutes.

A visually apparent usually symmetrical gradual (more than 30 sec) decrease in FHR and return to baseline associated with a contraction -nadir occurs at the same time as the peak of the contraction

visually apparent, usually symmetrical gradual decrease in FHR and return to baseline associate with a contraction -delayed in timing with the nadir occurring after the peak of the contraction

visually apparent abrupt decrease in FHR -decrease is 15 bpm lasting for more than 15 sec but less than 2 minutes

visually apparent decrease in FHR that is at least 15 bpm lasting greater than or equal to 2 minutes but less than 10 minutes from onset to return to baseline

a deceleration that lasts greater than or equal to 10 minutes

occurring the greater than or equal to 50% of contractions in a 20 minute period

occurring with less than 50% of contractions in a 20 minute period

visually apparent undulating sine wave like pattern in FHR and cycle frequency of 3-5 per minute which persists for greater than or equal to 20 minutes

-baseline 110-160 -moderate variability -no late or variable decels -present or absent early decels -present or absent accels

either -sinusoidal -absent variability with: recurrent lates, recurrent variables, or bradycardia

anything not in cat 1 or 3 -baseline bradycardia (not with absent variability) or tachycardia -minimal, marked, or absent (not with recurrent decels) variability -absence of induced accels after fetal stimulation -recurrent variables with minimal or moderate variability -prolonged decel 2-10 minutes long -recurrent lates with moderate variability

outside the fetus -placenta -maternal utero-placental circulation -fetal-placental circulation -placental transfer -uterine blood flow -umbilical cord -amniotic fluid

by simple diffusion

amniotic fluid volume is an indirect indicator of placental function

fetal homeostatic compensatory mechanisms -fetal circulation -ANS responses -baroreceptors -chemoreceptors -hormonal responses: redistribute blood flow

-decrease in utero-placental blood flow -stasis in intervillous spaces fetus relies on reserves

-baseline -variability -periodic/episodic changes -uterine activity: frequency, duration, intensity, resting tone

associated with contractions

not associated with contractions

normal fetal acid-base status -well oxygenated

baroreceptors - vagal nerve is stimulated

chemoreceptors

More than five uterine contractions in 10 minutes, averaged over a 30-minute window

200-250

-indirect: scalp stim, vibroacoustic stim -direct: umbilical cord sampling

-increased CO2 levels (>60) -occurs when fetal CO2 cant be easily diffused -can develop rapidly -can be corrected rapidly

-increased lactic acid levels (BD >12, BE <-12) -result from anaerobic metabolism -takes longer to develop -takes longer to correct

-pH: <7.10 acidosis -pCO2: >60 respiratory -BD: >12 (BE <-12) metabolic

detects heart sounds (baseline, rhythm, accels, decels) -verification of FHR arrhythmias

baseline, rhythm, accels, decels

-can determine CAT 1 and 2 -if CAT 2 put on EFM to determine variability

accelerations with the contractions

the fetal signal replaced by an alternate signal from the mother or another fetus

detects changes in shape of abdomen resulting from uterine tension

1. support maternal coping and labor progress 2. maximize uterine blood flow 3. maximize umbilical circulation 4. maximize oxygenation 5. maintain appropriate uterine activity

decreases catecholamine response and increases fetal oxygenation

-reduce anxiety/pain -maternal positioning (lateral) -hydration -medication to reduce uterine contractions (decrease pit or tocolytics)

-maternal position -amnioinfusion (closely monitor resting tone)

-maternal breathing -supplemental oxygen (cautious use, not 1st line, not for prophylactic use)

-oxytocin -fluid bolus -position change