fetal heart rate

fhr

- fetal heart rate

fhrb

- fetal hr baseline

efm

electronic fetal monitor

ua

uterine activity

uc

uterine contractions

us

ultrasound

toco

tocotransducer

fse

fetal scalp electrode

iupc

intrauterine pressure catheter

basis for fetal monitoring-uterine activity

- contraction, frequency, duration, intensity

- resting tone

- relaxation time

- montevideo units (MVUs)

types of fetal and uterine monitoring

- intermittent auscultation via doppler

- continuous external monitoring

- continuous internal monitoring

purpose of fetal monitoring

- to identify normal (reassuring) patterns from abnormal

indications for electronic fetal monitoring

- hx of stillbirth

- comp of pregnancy

- pre-gestation or gestational condition

- induction of labor (oxytocin)

- preterm labor

- non-reassuring fetal status

- meconium-stained amniotic fluid

advantages for fetal monitoring

- assess adequate o2 during labor

- make decisions r/t type of birth in a timely manner to avoid comp from early detection of complications

- can monitor trends

disadvantages of fetal monitoring

- ties mom to the bed in less than optimal position for labor and birth

- proof of potential problem for litigation

steps in interpreting fhr tracing

- is there enough of a continuous strip for interpretation (20min)

- identify fhr baseline

- identify variability: absent, minimal, moderate, or marked

- determine whether there are accelerations or decelerations (type)

- evaluate uterine contractions: freq, duration, intensity

- determine whether fhr is reassuring, nonreassuring, or ominous

- document interpretation of fhr, notify physician or midwife as appropriate

define frequency

- calculated in minutes

- beginning of one contraction to the beginning of the next contraction

define duration

- calculated in seconds

- beginning to end of a contraction

intensity

- mild, moderate, strong

- palpate uterine fundus for external monitoring

In the beginning of labor the contractions/uterus will be more squishy/moderate like your nose, then moderate as it progresses, then strong like your forehead. 

normal fhr

110-160

tachycardia

> 160 that lasts for at least 10 min

bradycardia

< 110 that lasts for at least 10 min

causes of tachycardia

- fetal hypoxia

- maternal fever

- hyperthyroidism

- maternal or fetal anemia

- parasympathetic drugs: atropine, hydroxyzine

- sympathomimetic drugs: ritodrine, terbutaline

- chorioamnionitis

- fetal tachyarrythmia

- prematurity

causes of severe fatal bradycardia

- prolonged cord compression

- cord prolapse

- tetanic uterine contractions

- paracervical block

- epidural and spinal anesthesia

- maternal seizures

- rapid descent

- vigourous vaginal exam

variability

The irregular waves or fluctuations in the baseline - beat to beat 

FHR of two cycles per minute. It does not include accelerations or decelerations.

It is quantified in beats per minute and is measured from the peak to the trough of a single cycle.

absent variability

- undetectable from baseline

- no accelerations or decelerations

minimal variability

- undetectable from baseline, <= 5bpm

moderate variability

6-25 bpm

- means good o2 and brain activity

- accelerations are okay

- fluctuating 1-2 blocks

marked variability

- no patterns, rapid accels but dont last 15, no time inbetween

>25 BPM

key concepts accels

- 32 wks or greater, 15 beats above baseline lasting 15 seconds

- before 32 wks, 10 beats or greater above baseline, lasting 10 or more seconds

- predict adequate fetal oxygenation and absence of fetal acidemia

early decels

- head compression can cause this esp toward end of labor

- little scoops of ice cream

- gradual onset > 30 sec from onset to nadir

- align with uterine contractions, returns to baseline by the end of contractions

slowing of the fetal heart rate starting at the beginning of the contraction and returning to the baseline by the end of the contraction

what is this?

early decels

variable decels

- no relationship w contractions, can happen w or w out

- no fixed time - ANYTIME

- cause: cord compression

- abrupt onest < 30 secs from onset to beginning of nadir, lasting > 15 secs but < 2 min

- depth: > 15bpm

- shapes: u, w, v

- very abrupt drop in heart rate

what is this?

variable decels

what is this?

variable decels

late decels

- caused by utero-placental insufficiency

- sign of fetal distress or hypoxia

- happens halfway or after contraction

- slowing or fhr during contraction, with the rate only returning to baseline 30 secs of more after contraction ended

- gradual onset > 30sec from onset to nadir, delayed in timing nadir after peak of contraction

- always take seriously

what is this?

late decels

prolonged decels

- abrupt decreases in fhr below baseline that is decreases of > 15 bpm lasting > 2min but less than 10 min

what is this?

prolonged decels

VEAL & CHOP

- variable: cord compression

- early: head compression

- accleration: okay (o2)

- late: placental insuff

tier classification cateory 1

- all normals

- fhr: 110-160

- moderate variability

- absent late or variable decels

- present or absent acels

- present or absent early decels

tier classification cateory 2

- bradycardia not accompanied by absent variability

- tachycardia not accompanied by absent variability

- baseline variability: minimal, absent, or marked

- no accelerations produced w fetal stimulation

- recurrent variables decels w overshoots or shoulders

- late decels, prolonged decels > 2 min but < 10min

tier classification cateory 3 - worst

- absent baseline variability and recurrent late decels, variable decels, or bradycardia

- sinusoidal pattern

causes & intervention category 1

- well oxygenated

- non acidotic

- intervention: cont efm, support labor

causes & interventions category 2

- not predictive cause

- intervention: cont efm, intiate some intrauterine resuscitation

causes & interventions cateogory 3

- acidosis, uteroplacental insuff, fetal hypoxia

- intervention: initiate intrauterine resuscitation

intrauterine resuscitation

- oxytocin off: to lessen the contractions and de-stress the baby 

- position change: esp cord compression

- ivfs (500 ml bolus): further pull circulation to fetus and help with oxygenation

- sterile vag exam

- notify hcp

- consider o2 if low o2 sat

- consider amnioinfusion: for variable, flush up inside uterus to help float

- consider tocolytics: stops contractions

- prepare woman for c section or imminent svd: especially with late decels or persisting ones

- do all these things if late decel