Fetal doppler & fetal growth

Post on 21-Jan-2018

578 views 5 download

transcript

MAGDY ABDELRAHMAN MOHAMED

Lecturer of OB/GYN

2015

Intrauterine growth restriction.

Fetal doppler.

Macrosomia.

Fetal weight below 10th percentile for

gestational age.

Incidence: 3-5%.

1st suspicion due to decrease fundal level

below expected from gestational age.

Types:

Symetrical.

Asymetrical.

Etiology:

Fetal.

Maternal.

Placental.

Fetal doppler.

BPP.

NST & contraction stress test.

WHY

Take decision of termination at proper time.

The Doppler effect was first described by

Christian Johann Doppler (1803–1853).

First use of Doppler ultrasonography to study

flow velocity in the fetal umbilical artery

was reported in 1977.

Echoes from stationary tissues are the samefrom pulse to pulse.

Echoes from moving objects exhibit slightdifferences in the time for the signal to bereturned to the receiver.

pulse repetition frequency

(T2 –T1) phase shift with known beam / flow angle

can calculate flow velocity .

T1

T2

the angle q between the beam and the

direction of flow becomes smaller.

qThe angle of insonation

Flow velocity

Factors affecting doppler frequency

Umbilical artery.

Uterine artery.

Middle cerebral artery.

Benefit of Umbilical Artery Evaluation

Less experienced operators can achieve

highly reproducible results with simple,

inexpensive continuous-wave equipment .

With advancing gestation,

umbilical arterial Doppler

waveforms demonstrate a

progressive rise in the

end-diastolic velocity and

a decrease in the

pulsatility index.

Umbilical artery

S/D ratio:

2-3 in 2nd & 3rd trimester

PI :

1.5 – 2.0 in 2nd trimester

1.0 – 1.5 in 3rd trimester

RI:

Decreases with gest. In

late 2nd and 3rd it is around

0.5

Risk to Neonate

More admissions to NICU

Increase ICH

Increase Anemia

Increase Hypoglycemia

Increase long term permanent neurological damage

High ResistanceReversal of Diastole

Cordocentesis was carried out in 39 IUGR fetuses

80% Hypoxic

46% Acidemic

Absent / Reverse Diastolic Flow

12% Hypoxic

00% Acidemic

Positive Diastolic Flow

Umbilical artery 90% more sensitivethan CTG.

Interval between absence of enddiastolic flow & onset of latedeceleration was 3-12 days.

REFLECTS : TROPHOBLASTIC INVASION

END POINTS :

ELEVATED RESISTIVE INDICES (> 2 SD).

PERSISTENT DIASTOLIC NOTCHING.

UTERINE ARTERY

Normal

impedance to

flow the uterine

arteries in 1st

trimester. Normal

impedance to

flow the uterine

arteries in early

2nd trimester.

Normal

impedance to

flow the uterine

arteries in late

2nd and 3rd

trimester.

Normal uterine artery Doppler Abnormal uterine artery Doppler

Abnormal Uterine Artery

Doppler Velocimetry

Peak systolic velocity can be used in

diagnosis of fetal anemia.

Def:

Fetal weight more than 90th

percentile.

> 4000 gm.

Risk factor:

Diabetes.

obesity.

High parity.

Prolonged pregnancy.

Previous history of macrosomia.

Excessive weight gain during pregnancy.

Diagnosis:

Estimated fetal weight.

AC > 90th percentile.

Increased S.C. fat thickness.