Polyhydramnios



Polyhydramnios


Roya Sohaey, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Idiopathic


  • Macrosomia


  • Diabetes


  • Hydrops


  • Twin-Twin Transfusion Syndrome


  • Fetal Bowel Obstruction


Less Common



  • Arthrogryposis, Akinesia Sequence


  • Skeletal Dysplasia, Severe


  • Chorioangioma


  • Cystic Adenomatoid Malformation


Rare but Important



  • Mesoblastic Nephroma


  • Unilateral Ureteropelvic Junction Obstruction


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Amniotic fluid index (AFI)



    • Divide uterus into 4 equal quadrants


    • Measure maximum vertical pocket (MVP)



      • Avoid fetal parts/cord in MVP


    • Add the 4 MVPs to calculate AFI


    • AFI/gestational age normogram tables available



      • > 24 cm AFI = polyhydramnios


  • Twin fluid assessment



    • Measure MVP for each fetus


    • ≥ 8 cm = polyhydramnios


Helpful Clues for Common Diagnoses



  • Idiopathic



    • Most common cause (2/3)



      • Mild, stable finding


    • Normal patient and fetus



      • No diabetes or fetal anomalies


    • 28% with fetal macrosomia


  • Macrosomia



    • Estimated fetal weight > 90th percentile


    • Large abdominal circumference is a hallmark finding



      • ↑ Truncal echogenic fat


    • Causes



      • Hereditary characteristics


      • Maternal obesity


      • Diabetes


      • Beckwith-Wiedemann syndrome


  • Diabetes



    • Gestational diabetes (most common)



      • Glucose intolerance during pregnancy


      • Oral glucose tolerance test given between 24-28 wks


    • Pregestational diabetes (type 1 or 2)


    • Polyhydramnios associated with poor glucose control



      • May be first finding in pregnancy


      • Associated with macrosomia


  • Hydrops



    • Excessive fetal fluid accumulation (2 or more body cavities)



      • Anasarca


      • Pleural effusion (± pericardial)


      • Ascites


    • Amniotic fluid may be ↑ or ↓


    • Immune hydrops (10%)



      • Hemolytic disease image fetal anemia


    • Non-immune (90%)



      • Infection


      • Any cause of fetal anemia


      • Any cause of fetal heart failure


      • Lymphatic obstruction


    • Aneuploidy associations



      • Turner syndrome (cystic hygroma)


      • Trisomy 21


      • Trisomy 18


  • Twin-Twin Transfusion Syndrome



    • Monochorionic twinning



      • Artery-to-vein anastomoses in shared placenta


      • Donor twin partly perfuses recipient twin


    • Fluid discrepancy may be 1st sign of developing twin-twin transfusion syndrome (need to follow carefully)


    • Recipient twin with polyhydramnios



      • Larger twin


    • Donor twin with oligohydramnios



      • Smaller “stuck” twin


  • Fetal Bowel Obstruction



    • Late polyhydramnios (> 24 wks)


    • Esophageal atresia



      • Absent or small stomach


      • 1/3 with trisomy 18 or 21


      • Associated with VACTERL syndrome


    • Duodenal atresia



      • “Double-bubble” appearance


      • 1/3 with trisomy 21


    • Jejunal, ileal atresia



      • “Sausage-shaped” bowel loops



Helpful Clues for Less Common Diagnoses



  • Arthrogryposis, Akinesia Sequence



    • Heterogeneous group of disorders



      • Lack of extremity motion


      • Contractures


    • Polyhydramnios from ↓ fetal movement/swallowing


    • Associations



      • Trisomy 18


      • Autosomal dominant and recessive syndromes


  • Skeletal Dysplasia, Severe



    • Common dysplasias



      • Thanatophoric


      • Achondroplasia


      • Achondrogenesis


      • Osteogenesis imperfecta


    • Common skeletal findings



      • Short limbs


      • Poor ossification


      • Bowed or broken bones


      • Craniosynostosis


    • Polyhydramnios common in 3rd trimester


  • Chorioangioma



    • Benign, vascular placental tumor


    • Large masses (> 5 cm): ↑ Complications


    • Polyhydramnios



      • Transudate from leaky vessels


    • Hydrops



      • Arteriovenous shunting in mass


      • Fetal anemia from hemolysis


  • Cystic Adenomatoid Malformation



    • Lung hamartoma


    • Microcystic and macrocystic types


    • Polyhydramnios etiology



      • Esophagus compression


      • Associated with hydrops


      • Mass may make fluid

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Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Polyhydramnios

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