Course Director

September 28-30, 2018

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Julia Bregand-White, MDUChicago Medicine

2018 University of Chicago Ultrasound SymposiumSeptember 29, 2018

Objectives Define normal amniotic fluid volume Describe methods of amniotic fluid volume assessment Review implications of abnormal amniotic fluid volume Review monitoring options in setting of abnormal

amniotic fluid volume

Disclosure I have no conflict of interest with respect to any of the

material presented in this lecture.

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Amniotic fluid

Increased incidence of fetal and neonatal morbidity and

mortality whether

too much or

too little

Amniotic Fluid- function1. Lung development2. Allows fetal movements (muscles, bones, joints)3. Thermoregulation4. Protects against infection5. Protects fetus from trauma6. Protects cord from compression

Amniotic Fluid‐ regulation

Secretion from respiratory tract

Transport across skin <20w Fetal urine >20w Intramembranous flow

INFLOW

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Amniotic Fluid‐ regulation

Fetal swallowing and reabsorption through GI tract

Transmembranous flow Transcervical (ruptured

membranes)

OUTFLOW

Amniotic Fluid‐ measurement Dye-determined amniotic fluid calculation Direct measurement at time of cesarean delivery Objective ultrasound assessment Subjective ultrasound assessment

Amniotic Fluid‐ volumeGestational age (weeks)

5th percentile 50th percentile 95th percentile

16 134 377 694

20 129 425 1986

24 129 469 3839

28 135 504 5016

34 157 538 3594

40 208 541 800

Sandlin AT, Ounpraseuth ST, Spencer HJ, et al: Amniotic fluid volume in normal singleton pregnancies: modeling with quantile regression. Arch Gynecol Obstet 289:967‐972, 2014

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Amniotic Fluid‐ volume

RA Brace, EJ Wolf: Normal amniotic fluid volume changes throughout pregnancy. Am J Obstet Gynecol. 161:382‐388 1989

Amniotic Fluid‐ measurement Amniotic Fluid Index (AFI) 4 Quadrants: umbilicus

divides the upper and lower halves and the linea nigradivides the right and left halves

Patient supine Linear (or curvilinear)

transducer is placed along the maternal anterior abdominal wall and held perpendicularto the floor

Amniotic Fluid‐ measurement Oligohydramnios

Less than 5cm Only 1% of AFI in term

pregnancies are <7cm (Moore 1990)

Polyhydramnios Greater than 25cm Gestational age specific

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Amniotic Fluid‐ measurement Maximum Vertical Pocket

(MVP; aka DVP, SDP) Largest single vertical

pocket of fluid that is at least 1 cm in width

Oligohydramnios <2cm

Severe <1cm

Polyhydramnios >8cm

Mild 8-12cm Severe >16cm

Amniotic Fluid‐ measurement 2D Pocket

Horizontal and vertical dimensions of the maximum vertical pocket

Multiply values together to obtain a single value, in cm2

Normal 15-50cm2

Amniotic Fluid‐ measurement

Subjective Assessment Visual interpretation

without ultrasound measurements

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Amniotic Fluid‐ measurement

When in doubt, put color on…

Increased false positive oligohydramnios

EF Magann, SP Chauhan, S Barrilleaux, et al.: Ultrasound estimate of amniotic fluid volume: color Doppler overdiagnosis of oligohydramnios. Obstet Gyncol. 98:71‐74 2001

Amniotic Fluid‐ measurement Limitations

Excessive pressure Adipose tissue causing artificial echoes Fetal position

Not typically effected by Maternal positions Fetal movement Curvilinear or sector transducer

Amniotic Fluid‐ which is best?

Dye determined is as good as direct measurement at time of cesarean delivery

Thanks but no thanks!

EF Magann, NS Whitworth, JC Files, et al.: Dye‐dilution techniques using aminohippurate sodium: do they accurately reflect amniotic fluid volume?. J MaternFetal Neonatal Med  11:167‐170 2002

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Amniotic Fluid‐ which is best? AFI and MVP reliably identify normal AFV Not as accurate when fluid is abnormal1

No difference in subjective vs objective assessment2

A normal AFV varies during gestation and depends on the population being investigated

1‐ SP Chauhan, EF Magann, JC Morrison, et al.: Ultrasonographic assessment of amniotic fluid does not reflect actual amniotic fluid volume. Am J Obstet Gynecol. 177:291‐296 19972‐Magann, SP Chauhan, NS Whitworth, et al.: Subjective versus objective evaluation of amniotic fluid volume of pregnancies of less than 24 weeks’ gestation: how can we be accurate?. J Ultrasound Med. 20:191‐195 2001

Amniotic Fluid‐ which is best? Cochrane Review 2008

5 RCT: 3226 women 

No superior method to prevent poor peripartumoutcomes  NICU admission

Umbilical artery pH <7.1

AFI associated with more Oligohydramnios 

Inductions of labor 

C/S for FHR abnormalities 

Diagnosis of Oligohydramnios

Rate of Induction of Labor

AF Nabhan, YA Abdelmoula: Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome. Cochrane Database Syst Rev.

Amniotic Fluid‐ which is best? MVP was the better measurement because the use of the AFI increased the diagnosis of oligohydramnios and labor inductions without improvement in peripartum outcomes

AF Nabhan, YA Abdelmoula: Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome. Cochrane Database Syst Rev.

Amniotic Fluid – Too Little, Too Much –Bregand‐White

too little

Oligohydramnios‐ definition Too little

AFV <200 (500cc) AFI < 5cm MVP <2cm 2D pocket <15cm2

Oligohydramnios- outcomesSeverity of Oligo Oligo vs normal

Perinatal mortality: Normal fluid (2cm<MVP<8cm)

1.97/1000

Marginal fluid (MVP 1-2cm) 37.7/1000

Low fluid (MVP <1cm) 109.4/1000

NO difference in perinatal outcomes Cesarean delivery for fetal

labor intolerance Umbilical cord arterial pH of

less than 7 NICU admissions Seizures in the first 24 hours

after delivery Neonatal death

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Oligohydramnios- etiologyProduction vs Obstruction vs Loss

Prerenal Placental insufficiency Fetal demise Maternal hypovolemia

Renal Renal agenesis Cystic dysplastic kidneys Maternal medications- ACE-I, ARB, NSAID

Postrenal Bilateral UPJ obstruction Posterior urethral valves Ruptured membranes

Rule out ruptured membranes!

Oligohydramnios- evaluation After you’ve ruled out ruptured membranes… History and physical looking for risk factors for utero-

placental insufficiency Chronic kidney disease Chronic hypertension Placental abruption

Targeted ultrasound Fetal anomalies Fetal growth Fetal well-being

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Oligohydramnios- management Dependent on etiology

Renal agenesis- options counseling Medication exposure- stop offending agent Dehydration- hydration

Increased antenatal testing Weekly assessment of AFV: consider NST, BPP Fetal growth monitoring: US every 3-4 weeks

Delivery timing Oligohydramnios at term is generally considered an

indication for delivery

TOO MUCH

Polyhydramnios- definition Complicates 0.2-2% of pregnancies

Stratified by Severity Mild: AFI 25-30cm SDV 8-11cm Moderate: AFI 30-35cm SDV 2-15cm Severe: AFI >35.1cm SDV >16cm

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Polyhydramnios- etiology Idiopathic (aka I have no idea)

50-60% of cases Congenital anomalies and genetic disorders

8-45% Maternal diabetes

5-26% Multiple gestations

8-10% Fetal anemia

1-11% Other- hydrops, Bartter syndrome, viral infections

Polyhydramnios- etiology Severity implicates likelihood of finding fetal anomaly

Mild: 17% Moderate: 72% Severe: 86%

N Damato, RA Filly, RB Goldstein, et al.: Frequency of fetal anomalies in sonographically detected polyhydramnios. J Ultrasound Med. 12 (1):11‐15 1993

Polyhydramnios- etiology Congenital anomalies

Central nervous system 28% Anencephaly, holoprosencephaly,

spina bifida

Cardiac 22% High output cardiac failure (fetal

anemia, fetal/placental tumors)

Gastrointestinal malformation 14% Small bowel atresia or

obstruction

Other Facial/neck tumors, cleft lip/palate

MS Nobile de Santis, T Radaelli, E Taricco, et al.: Excess of amniotic fluid: pathophysiology, correlated diseases and clinical management. Acta Biomed. 75 (Suppl 1):53‐55 2004

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Polyhydramnios- implications Risk of aneuploidy

10% poly + anomaly Trisomies 21, 18, 13

1% if poly alone

Severe persistent poly in the 2nd and 3rd trimesters is associated with a higher incidence of aneuploidy Warrants amniocentesis

A Golan, I Worman, J Sagi, et al.: Persistence of polyhydramnios during pregnancy: its significance and correlation with maternal and fetal complications. Gynecol Obstet Invest. 37:18‐20 1994

Polyhydramnios- evaluation History and physical looking for risk factors for associated

conditions Pre-gestational or gestational diabetes

Lab Maternal antibody screen, diabetic screen TORCH, parvovirus

Targeted ultrasound Fetal anomalies Fetal growth Fetal echo Fetal well-being Consider amniocentesis- genetic and infectious

MFM Consultation

Polyhydramnios- adverse outcomes Preterm labor Maternal respiratory distress Malpresentation Placental abruption Cord prolapse Postpartum hemorrhage

Perinatal mortality odds ratio 5.5

E Maymon, F Ghezzi, I Shoham‐Vardi, et al.: Isolated hydramnios at term gestation and the occurrence of peripartum complications. Eur J Obstet GynecolReprod Biol. 77:157‐161 1998

Amniotic Fluid – Too Little, Too Much –Bregand‐White

Polyhydramnios- management Antenatal testing

Consider antenatal testing with AFV assessment at least weekly Multidisciplinary team approach

In setting of severe persistent polyhydramnios where risk fo aneuploidy and/or fetal anomaly are high

MFM, NICU, genetic counselors, pediatric surgeons, pediatric cardiologist, SW

Interventions Amniocentesis- large volume reduction Indomethacin- 2.2-3mg/kg/day for short course prior to 32w

Delivery timing Consider delivery at 39w in the setting of mild poly, appropriate antenatal

testing and minimal maternal symptoms Consider delivery earlier if severe poly or uncontrolled maternal

symptoms

Thank you!