How is polyhydramnios managed?

Management of Polyhydramnios

Polyhydramnios management should include a thorough evaluation for underlying causes, with treatment directed at the specific etiology when identified, and consideration of interventional procedures only for severe symptomatic cases. 1, 2

Definition and Diagnosis

• Polyhydramnios is defined as:
  • Deep Vertical Pocket (DVP) ≥8 cm, or
  • Amniotic Fluid Index (AFI) ≥24 cm 3, 2
• Normal amniotic fluid is defined as DVP between 2-8 cm 3
• The DVP method has better clinical utility than AFI, with fewer false positives and reduced unnecessary interventions 3

Evaluation of Polyhydramnios

1. Search for underlying etiology:

   • Maternal diabetes mellitus (most common pathologic cause)
   • Fetal anomalies (especially those affecting swallowing or urination)
   • Genetic syndromes
   • Congenital infections
   • Twin-twin transfusion syndrome (in monochorionic twins)
   • Alloimmunization 2

2. Recommended workup:

   • Detailed fetal anatomical survey
   • Fetal echocardiography
   • Maternal diabetes screening
   • TORCH serology (for infections)
   • Consider genetic testing 3, 2

Management Approach

Mild Idiopathic Polyhydramnios

• Antenatal fetal surveillance is not required for mild idiopathic polyhydramnios 2
• Allow labor to occur spontaneously at term
• If induction is planned, it should not occur before 39 weeks in the absence of other indications
• Mode of delivery should be determined based on usual obstetric indications 2

Moderate to Severe Polyhydramnios

• Antenatal fetal surveillance is indicated 3
• Delivery at a tertiary care center is recommended due to significant possibility of fetal anomalies 2
• Monitor for maternal complications:
  • Dyspnea
  • Preterm labor
  • Premature rupture of membranes
  • Abnormal fetal presentation
  • Risk of cord prolapse
  • Postpartum hemorrhage 4

Interventional Management for Severe Polyhydramnios

1. Amnioreduction:

   • Consider only for severe maternal discomfort or dyspnea in the setting of severe polyhydramnios
   • Not routinely recommended for mild to moderate cases 2
   • In pregnancies complicated by polyhydramnios, serial amniocenteses may be used to prolong pregnancy, but benefits have not been evaluated in prospective studies 1

2. Pharmacological treatment:

   • NSAIDs (such as indomethacin) are not recommended for the sole purpose of decreasing amniotic fluid 2
   • If maternal NSAID therapy is considered:
     • Close monitoring with fetal echocardiography is mandatory
     • Risks include fetal ductus arteriosus constriction, enterocolitis, intestinal perforation, and necrotizing enterocolitis 1
     • A multidisciplinary perinatal team should be involved, including maternal-fetal medicine specialist, neonatologist, pediatric cardiologist, and pediatric nephrologist 1

Special Considerations for Twin Pregnancies

• For monochorionic diamniotic twin pregnancies:
  • Begin ultrasound surveillance at 16 weeks
  • Continue at least every 2 weeks until delivery 3
  • For twin-twin transfusion syndrome with polyhydramnios in recipient twin:
    • Fetoscopic laser surgery is recommended for stage II-IV TTTS between 16-26 weeks 1
    • Expectant management with weekly surveillance for stage I TTTS 1

Prognosis and Risks

• Polyhydramnios is independently associated with:
  • Increased perinatal mortality (OR 5.8,95% CI 3.68-9.11)
  • Increased risk of stillbirth (OR 1.8,95% CI 1.4-2.2)
  • Risk of fetal anomalies increases with severity of polyhydramnios 3

Monitoring After Resolution

• If polyhydramnios resolves (spontaneously or after treatment), continue appropriate fetal surveillance based on underlying condition
• For twin pregnancies after laser therapy for TTTS:
  • Weekly surveillance for 6 weeks
  • Then every-other-week surveillance thereafter 1

The management of polyhydramnios requires careful consideration of the underlying cause, severity of the condition, and gestational age, with interventions reserved primarily for severe symptomatic cases.