fetal monitoring & wellbeing

Principles:

the ideal scheme to assess FWB should:

Take account of cycles of normal fetal behavior

detect impending harm accurately and in time to intervene to prevent it

give reassurance preferably up to 7 days

avoid causing unnecessary anxiety

allow detection of specific causes e.g hypoxia, infection, malf’n

produce measurable benefits in reducing perinatal loss/injury

such system is likely to involve tests which assess several fetal systems, CVS, NS,, RS and use >1 modality

Factors for increased fetal risk

• Medical complications:

HTN, DM, AID, Hb pathies

• Fetal problems:

IUGR, Non-lethal anamolies, prematurity, postdatism, hydrops

• IU problems:

Bleeding, fever, meconium stain, oxytocin augment.

Utero-placental complex

•Uterus depends on placenta for diffusion of nutrients and respiratory gas exchange.

•Placental function depends on uterine blood flow (UBF)

•Uterine contraction leads to transient decreased UBF

•Borderline placenta may lead to fetal asphyxia during L&D

•Fetal compensatory responses limit the damage

•Prolonged or severe hypoxia may cause injury or death.

Non-invasive:

Fetal Movement Count:

Fetal Heart Recording….. CTG

Biophysical Profile {BPP} scoring

Doppler studies

Invasive:

• Chorion villus Sampling

•Amniocentesis

•Umbilical artery canulation

Intrapartum Fetal Assessment

• Electronic Fetal Heart Monitoring

• Fetal Scalp pH ( and pCo2, pO2) Monitoring

• Fetal Scalp Stimulation

• Vibroacoustic Stimulation

• UA Velocimetry and Biophysical profile

• Fetal Pulse Oximetry

• Near-infrared Spectroscopy

Screening tool to assess the fetal state of oxygenation and predicts early signs of hypoxia and fetal distress.

• Stimulus: Contractions/ fetal movements

• Baseline fetal heart rate

• Baseline variability

• Accelerations

• Decelerations

baseline heart rate

Baseline variability

Classification:

Silent 0-5 bpm

Reduced 6-10 bpm

Normal 11-25 bpm

Saltatory >25 bpm

accelerations

Decelerations:

Decelerations:

Basal fetal oxygenation. The relationship of late decelerations to baseline fetal oxygenation during contractions

Signature +

Date & Time

DEFINE

RISK

CONTRACTIONS

BASELINE

RATE

VARIABILITY

ACCELERAT’N

DECELERAT’N

OVER ALL ASSESSMENT

• Baseline Rate 110-150 bpm

• Amplitude of baseline variability 5/10-25 bpm

• Absence of decelerations, except for fleeting& short

• Presence of 2 or more accelerations during a 20 min period

• Baseline rate of 150-170 bpm/ 100-110 bpm

• Amplitude of variability bn 5-10 bpm > 40 min

• Increased variability above 25 bpm {saltatory}

• Absence of accelerations for > 40 min

• Sporadic decelerations of any type, unless severe

• Baseline heart rate < 100 bpm or > 170 bpm

• Variability < 5 bpm for > 40 min

• Recurrent decelerations of any type

• Severe variable or late decelerations

• A sinusoidal pattern

Any of the following:

Indications of use:

pregnancy location

viability

fetal number

dating

anomaly

placental localization, amniotic fluid

fetal growth and wellbeing

during invasive procedures

Assessment of gestational age and fetal growth:

menstrual history unreliable in up to 45% of women

serial fundal height measurement provides a guide to fetal growth

USS: crown-rump length before 14 weeks

USS: BPD serial measurement every 2 weeks for fetal growth. Unreliable after 28 weeks for dating

USS: head/abd ratio, 2 weeks serial HC & AC for fetal growth .. IUGR AC< but initially HC ~.

USS: femur length, more precise guide to gestational age than BPD

Serial measurements are necessary to identify the growth pattern and detect any lag in the growth and IUGR

Biophysical ProfileBiophysical Profile& &

Color Doppler ultrasound Color Doppler ultrasound

in the high risk pregnancyin the high risk pregnancy

•BPP is applying to detect prenatal

asphyxia

•Doppler ultrasound is a modality for

detecting fetal hypoxia and acidosis

•Doppler can also predict later pre-

eclampsia at the 24-26 gestational weeks.

•Hypoxia: Low Oxygen tension

•Asphyxia: Low Oxygen and high CO2

•Ischemia: Drop in blood flow

BPP uses FHR monitor and real time USS to assess:

fetal breathing movement

discrete body or limb movement

fetal tone

FHR

amniotic fluid volume

Amniotic fluid volume is most important

Fetal breathing movement is the first to disappear in asphyxia

7 days reassurance in low risk, only 24 hours in high risk preg

ComponentComponent DefinitionDefinitionFetal movements3 body or limb movements

Fetal toneOne episode of active extension and flexion of the limbs; opening and

closing of hand

Fetal breathing movement

episode of >= 30 seconds in 30 minutes Hiccups are considered

breathing activity.

Amniotic fluid volumesingle 2 cm x 2 cm pocket is considered adequate.

Non-stress test2 accelerations > 15 beats per minute of at least 15 seconds duration.

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•As you know, oligohydramnios may be

• Mild AFI=5-8cm

•Moderate AFI=2-5cm

•Sever AFI<2cm

only sever oligohydramnios is considered as an

abnormal score.

•Fetal movement and fetal tone develop

between 7.5 and 9 weeks’ menstrual age

•Fetal breathing movements are

detectable by, at least 17-18 weeks’

gestation

•The non-stress test is most reliable

between 32 weeks and term (Ware, 1994).

An early stage in fetal adaptation to hypoxemia

-central redistribution of blood flow (brain-sparing reflex)

-increased blood flow to protect the brain, heart, and adrenals

-reduced flow to the peripheral and placental circulations

Umbilical arteryUmbilical artery

Clinical Indications for Doppler Studies

most useful in assessing IUGR

identify only the sub-group which is hypoxemic bec/of inadequate placental function and may be abnormal for up to 18 weeks before any fetal problem is observed

no proven role in population screening for increased risk of pre-eclampsia or IUGR