What are the possible causes of polyhydramnios (excess amniotic fluid) at 22 weeks of gestation?

From the Guidelines

Polyhydramnios at 22 weeks is most likely caused by maternal diabetes mellitus, fetal structural anomalies, chromosomal abnormalities, multiple gestation pregnancies, or certain fetal infections. The possible causes of polyhydramnios at 22 weeks can be broken down into several key categories, including:

• Maternal factors: diabetes mellitus, which affects fetal swallowing and urination patterns 1
• Fetal structural anomalies: gastrointestinal obstructions (esophageal or duodenal atresia), neurological disorders affecting swallowing (anencephaly), or thoracic abnormalities 1
• Chromosomal abnormalities: trisomy 21,18, or 13 1
• Multiple gestation pregnancies: particularly with twin-to-twin transfusion syndrome 1
• Fetal infections: cytomegalovirus or parvovirus B19 1 It is essential to note that idiopathic polyhydramnios, where no specific cause is identified, accounts for about 60% of cases 1. When polyhydramnios is detected at 22 weeks, a detailed ultrasound assessment should be performed to evaluate fetal anatomy, followed by consideration of amniocentesis for genetic testing and infection screening. Additionally, maternal glucose tolerance testing is also essential to rule out gestational diabetes 1. The severity and progression of polyhydramnios will determine management, which may range from monitoring to therapeutic amniocentesis in severe cases 1. It is crucial to prioritize the management of polyhydramnios to minimize the risk of adverse outcomes, such as preterm labor and fetal distress 1.

From the Research

Possible Causes of Polyhydramnios at 22 Weeks

• Maternal diabetes mellitus 2, 3, 4
• Fetal anomalies, such as esophageal atresia, duodenal atresia, and other congenital abnormalities 2, 3, 4, 5, 6
• Fetal infections 2, 3
• Congenital infection and alloimmunization 3
• Idiopathic reasons, which are the most common cause of mild polyhydramnios 3, 4
• Chromosomal disorders 4
• Isoimmunologic disease 4
• Multiple gestations 4
• Gut atresia, which can cause polyhydramnios due to the fetus's inability to swallow and absorb amniotic fluid 5

Fetal Anomalies Associated with Polyhydramnios

• Esophageal atresia, which can cause polyhydramnios due to the fetus's inability to swallow amniotic fluid 5, 6
• Duodenal atresia, which can cause polyhydramnios due to the fetus's inability to absorb amniotic fluid 5
• Other congenital abnormalities, such as intestinal atresia and stenosis 5