What is the definition of polyhydramnios (excess of amniotic fluid)?

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Last updated: April 17, 2025 • View editorial policy

From the Guidelines

Polyhydramnios is defined as an amniotic fluid volume with a maximal vertical pocket (MVP) > 8 cm or an amniotic fluid index (AFI) > 25 cm or >95th percentile for gestational age. This definition is based on the most recent and highest quality study available, which emphasizes the importance of accurate assessment of amniotic fluid volume in fetal well-being 1. The assessment of amniotic fluid volume is a crucial component of both the modified biophysical profile (mBPP) and the biophysical profile (BPP), as it can help identify potential complications and guide clinical decision-making.

Key points to consider in the definition and management of polyhydramnios include:

  • The maximal vertical pocket of amniotic fluid may be a more reliable indicator of polyhydramnios than the amniotic fluid index 1
  • Polyhydramnios is associated with an increased risk of adverse fetal outcomes, including perinatal mortality and stillbirth 1
  • The condition can be caused by various factors, including maternal conditions, fetal anomalies, and multiple pregnancies
  • Management of polyhydramnios depends on the severity and underlying cause, and may include monitoring, therapeutic amniocentesis, and other interventions to reduce the risk of complications.

It is essential to note that polyhydramnios can have significant implications for maternal and fetal well-being, and accurate diagnosis and management are critical to preventing adverse outcomes 1.

From the Research

Definition of Polyhydramnios

  • Polyhydramnios is defined as a pathological increase of amniotic fluid volume in pregnancy 2
  • This condition is associated with increased perinatal morbidity and mortality 2

Key Characteristics

  • Common causes of polyhydramnios include: + Gestational diabetes + Fetal anomalies with disturbed fetal swallowing of amniotic fluid + Fetal infections and other, rarer causes 2
  • Diagnosis is typically obtained by ultrasound 2
  • Prognosis depends on the cause and severity of polyhydramnios 2

Symptoms and Complications

  • Typical symptoms of polyhydramnios include: + Maternal dyspnea + Preterm labor + Premature rupture of membranes (PPROM) + Abnormal fetal presentation + Cord prolapse + Postpartum hemorrhage 2
  • Often associated with fetal macrosomia due to its common etiology with gestational diabetes 2

References

Guideline

acr appropriateness criteria assessment of fetal well-being.

Journal of the American College of Radiology, 2016

Research

Polyhydramnios: Causes, Diagnosis and Therapy.

Geburtshilfe und Frauenheilkunde, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.