AMNIOTIC FLUID AMNIOTIC FLUID USUS

Dr. Doaa Dr. Doaa IraqiIraqi

M.SC.M.SC.

Amniotic fluid volume Amniotic fluid volume ((AFVAFV) ) should be assessed either should be assessed either qualitatively or quantitatively at every antenatal ultrasound qualitatively or quantitatively at every antenatal ultrasound

examinationexamination..

There are a variety of reasons for this There are a variety of reasons for this recommendationrecommendation::

premature rupture of membranespremature rupture of membranes Reduced or Reduced or absent amniotic fluid is suggestive, but not absent amniotic fluid is suggestive, but not diagnostic.diagnostic.

Fetal congenital anomaliesFetal congenital anomalies ((eg, gastrointestinal or eg, gastrointestinal or urinary tract obstructionurinary tract obstruction)), chromosomal , chromosomal abnormalities abnormalities ((eg, trisomy 18eg, trisomy 18))..

fetal growth restrictionfetal growth restriction can be associated with can be associated with abnormalities of amniotic fluid volumeabnormalities of amniotic fluid volume

. . Thus, assessment of amniotic fluid volume is one of Thus, assessment of amniotic fluid volume is one of several parameters used in antenatal fetal several parameters used in antenatal fetal surveillancesurveillance

Criteria for CodingCriteria for Coding Fetal BiophysicalFetal Biophysical Variables as NormalVariables as Normal

fetal breathing movementsfetal breathing movements :1 or more episodes of ≥20 s :1 or more episodes of ≥20 s within 30 min.within 30 min.

Gross body movementsGross body movements : 2 or more discrete body/ limb : 2 or more discrete body/ limb movements within 30 min.movements within 30 min.

Fetal toneFetal tone :1 or more episodes of active extension with :1 or more episodes of active extension with return to flexion of fetal limb(s) or trunk .return to flexion of fetal limb(s) or trunk .

Reactive FHRReactive FHR :2 or more episodes of acceleration of :2 or more episodes of acceleration of ≥15 beats per minute (bpm) and of >15 s associated ≥15 beats per minute (bpm) and of >15 s associated with fetal movement within 20 min .with fetal movement within 20 min .

Qualitative AFVQualitative AFV :1 or more pockets of fluid measuring :1 or more pockets of fluid measuring ≥2 cm in vertical axis .≥2 cm in vertical axis .

Maximum vertical pocketMaximum vertical pocket

One ultrasound method of assessing the One ultrasound method of assessing the AF is to AF is to measure the depth of the largest measure the depth of the largest visible pocket of fluidvisible pocket of fluid surrounding the surrounding the fetusfetus. . The normal range The normal range is is 2 cm to 8 cm in 2 cm to 8 cm in singleton gestationssingleton gestations. . The normal range for The normal range for the single deepest pocket the single deepest pocket in twin gestation in twin gestation appears to be 2.2 cm to 7.5 cm.appears to be 2.2 cm to 7.5 cm.

Maximum vertical pocketMaximum vertical pocket

severe oligohydramniossevere oligohydramnios < 1 cm.< 1 cm. mild oligohydramnios mild oligohydramnios >> 1 and 1 and < < 2 cm.2 cm. NormalNormal polyhydramniospolyhydramnios>> 8 and < 12 cm . 8 and < 12 cm . moderate polyhydramnios moderate polyhydramnios >>12 cm and < 12 cm and <

16.16. severe polyhydramnios severe polyhydramnios >> 16 cm. 16 cm.

Maximum vertical pocketMaximum vertical pocket

Amniotic Fluid IndexAmniotic Fluid Index The AFI is a semiquantitative method for evaluating the AFVThe AFI is a semiquantitative method for evaluating the AFV. . The The

AFI is derived by adding the largest vertically measured fluid pocket AFI is derived by adding the largest vertically measured fluid pocket from each uterine quadrantfrom each uterine quadrant.. This method appears to be at least as This method appears to be at least as accurate as the largest–pocketaccurate as the largest–pocket--ofof--fluid method . fluid method . Using this method, Using this method, the normal range for the AFI is 5 to 25 cmthe normal range for the AFI is 5 to 25 cm . . oligohydramnios is oligohydramnios is defined as an AFI of less than 5defined as an AFI of less than 5. .

To obtain an AFI, the mother must be in the supine position and the To obtain an AFI, the mother must be in the supine position and the linear ultrasonographic probe must be parallel to the maternal spine linear ultrasonographic probe must be parallel to the maternal spine and perpendicular to the floor for all measurements. The abdomen and perpendicular to the floor for all measurements. The abdomen is divided into 4 quadrants, with the umbilicus delineating the upper is divided into 4 quadrants, with the umbilicus delineating the upper and lower halves and the linea nigra delineating the left and right and lower halves and the linea nigra delineating the left and right halves.halves.

The largest pocket of fluid in each quadrant is measured along the The largest pocket of fluid in each quadrant is measured along the vertical dimension, which is the dimension perpendicular to the vertical dimension, which is the dimension perpendicular to the ultrasonographic probe. The pockets must be free of umbilical cord ultrasonographic probe. The pockets must be free of umbilical cord or fetal extremities, although brief appearances of these are or fetal extremities, although brief appearances of these are acceptable. The video below demonstrates measurement of the acceptable. The video below demonstrates measurement of the AFI.AFI.

Some causes of polyhydramnios Some causes of polyhydramnios ((too much amniotic fluidtoo much amniotic fluid))]]

Idiopathic Idiopathic ((unknownunknown) ) ~ most cases~ most cases Gastrointestinal abnormalitiesGastrointestinal abnormalities

Esophageal atresiaEsophageal atresia Intestinal obstructionIntestinal obstruction

Central nervous system abnormalitiesCentral nervous system abnormalities AnencephalyAnencephaly

Chromosomal abnormalitiesChromosomal abnormalities Nonimmune hydropsNonimmune hydrops Skeletal dysplasiasSkeletal dysplasias DiabetesDiabetes TwinTwin- - to to --twin transfusiontwin transfusion

Some causes of Some causes of oligohydramnios oligohydramnios ((too little too little

amniotic fluidamniotic fluid)) Ruptured membranesRuptured membranes Congenital abnormalitiesCongenital abnormalities

Bilateral renal agenesis or cystic dyplasiaBilateral renal agenesis or cystic dyplasia Obstruction of the urinary tractObstruction of the urinary tract MeckelMeckel--Gruber syndromeGruber syndrome VACTERL VACTERL ((vertebral, anal, cardiac, tracheovertebral, anal, cardiac, tracheo--esophageal, renal, limbesophageal, renal, limb) )

associationassociation SirenomeliaSirenomelia Sacral agenesisSacral agenesis

Growth restriction Growth restriction ((placental insufficiencyplacental insufficiency) ) Postterm pregnancyPostterm pregnancy DrugsDrugs::AngiotensinAngiotensin--converting enzyme inhibitorsconverting enzyme inhibitors

Prostaglandin synthase inhibitorsProstaglandin synthase inhibitors TwinTwin- - to to --twin transfusiontwin transfusion TRAP TRAP ((twin reverse arterial perfusion sequencetwin reverse arterial perfusion sequence) ) Fetal demiseFetal demise IdiopathicIdiopathic

excess amniotic fluid excess amniotic fluid ((the largest single the largest single pocket measuring 11 pocket measuring 11 cmscms. . approximatelyapproximately). ). This suggests mild to This suggests mild to moderate moderate polyhydramniospolyhydramnios. . Particulate matter Particulate matter seen in the fluid is due seen in the fluid is due to fetal meconiumto fetal meconium. .

Severe oligohydramnios in late 2nd Severe oligohydramnios in late 2nd trimestertrimester

Among the Causes of Among the Causes of oligohydramnios areoligohydramnios are- - premature rupture of premature rupture of membranes, Fetal hypoxaemia, membranes, Fetal hypoxaemia, renal agenesis or dysgenesis, renal agenesis or dysgenesis, intake of certain drugs, Fetal intake of certain drugs, Fetal demise and also Fetal IUGRdemise and also Fetal IUGR. . oligohydramnios is diagnosed oligohydramnios is diagnosed when the four quadrant AFI or when the four quadrant AFI or amniotic fluid index is less than amniotic fluid index is less than five or the maximum vertical five or the maximum vertical fluid pocket is less than 2 cmfluid pocket is less than 2 cm. . Among the complications of Among the complications of such severe oligohydramnios such severe oligohydramnios are Fetal limb contractures and are Fetal limb contractures and Fetal lung hypoplasiaFetal lung hypoplasia. .

Hyperechoic amniotic fluidHyperechoic amniotic fluid/ / LiquorLiquor

Increased echogenicity of Increased echogenicity of Liqor amni These ultrasound Liqor amni These ultrasound images reveal markedly images reveal markedly echogenic echogenic ((hyperechoichyperechoic) ) amniotic fluidamniotic fluid. . The fluid shows The fluid shows almost the same echogenicity almost the same echogenicity as the placentaas the placenta. . Such Such appearances of the liquor appearances of the liquor amni on sonography are seen amni on sonography are seen due presence of vernix due presence of vernix caseosacaseosa ( (commonest causecommonest cause)), , Very echogenic amniotic fluid Very echogenic amniotic fluid has been variably attributed to has been variably attributed to meconium, blood, or vernix meconium, blood, or vernix caseosacaseosa..

This 21 week gestation had labour contractions with leaking This 21 week gestation had labour contractions with leaking per vaginumper vaginum. . On color doppler scan, the internal os appears On color doppler scan, the internal os appears

dilated with umbilical cord seen within the cervixdilated with umbilical cord seen within the cervix. . These These ultrasound and color doppler images are diagnostic of ultrasound and color doppler images are diagnostic of

umbilical cord prolapseumbilical cord prolapse . .

Routine obstetric sonography was done on this patientRoutine obstetric sonography was done on this patient . . Images reveal a Images reveal a cystic lesion in the umbilical cord close to the cystic lesion in the umbilical cord close to the fetal abdomenfetal abdomen. . On color doppler scan, On color doppler scan, flow is presentflow is present in the in the cystic area which shows continuity with the umbilical veincystic area which shows continuity with the umbilical vein. .

These ultrasound and color doppler images These ultrasound and color doppler images suggest suggest umbilical vein varix umbilical vein varix ((within the cord)within the cord) .( .(

The normal umbilical cord with three vessels within it The normal umbilical cord with three vessels within it (compare with the 2 vessel cord). Cross section ultrasound (compare with the 2 vessel cord). Cross section ultrasound

images of the normal umbilical cord show 2 umbilical arteries images of the normal umbilical cord show 2 umbilical arteries (the smaller caliber vessels) and the larger caliber umbilical (the smaller caliber vessels) and the larger caliber umbilical

veinvein . .

there is only one umbilical artery and an umbilical vein within there is only one umbilical artery and an umbilical vein within this cordthis cord. . This ultrasound finding is called a single umbilical This ultrasound finding is called a single umbilical

artery artery ((SUASUA) ) or 2 vessel cord and is associated with or 2 vessel cord and is associated with increased fetal morbidity including singleincreased fetal morbidity including single/ / multiple fetal multiple fetal congenital anomalies, still birth and premature deliverycongenital anomalies, still birth and premature delivery . .

سبحانك اللهم و بحمدك اشهد ان ال اله سبحانك اللهم و بحمدك اشهد ان ال اله إال انت استغفرك و اتوب اليكإال انت استغفرك و اتوب اليك