What are the causes of polyhydramnios?

Jul 18, 2025 Source: Cainiu Health

Dr. Zhang Lu

Introduction

In general, polyhydramnios (excessive amniotic fluid) may be caused by gestational diabetes, fetal developmental factors, fetal gastrointestinal malformations, fetal urinary system malformations, or maternal-fetal blood type incompatibility during pregnancy. It is recommended to seek timely medical attention, identify the underlying cause, and undergo symptomatic treatment under a doctor's guidance. Daily, maintain a regular作息 (作息 translates to作息 schedule or routine), avoid fatigue, and attend regular prenatal checkups.

Generally, polyhydramnios (excessive amniotic fluid) may be caused by gestational diabetes, fetal developmental factors, fetal gastrointestinal malformations, fetal urinary system malformations, or maternal-fetal blood type incompatibility during pregnancy. It is recommended to seek timely medical consultation to determine the underlying cause and receive symptomatic treatment under a physician's guidance. Detailed analysis is as follows:

1. Gestational Diabetes: Poor maternal glycemic control leads to elevated fetal blood glucose, causing hyperosmotic diuresis and excessive amniotic fluid production, often accompanied by polydipsia, polyphagia, and polyuria, particularly during the middle and late stages of pregnancy. Patients should regulate their diet, reduce intake of high-sugar foods, follow medical advice for insulin injection to control blood glucose levels, and regularly monitor both blood glucose and amniotic fluid volume. Excessive amniotic fluid may improve once blood glucose stabilizes.

2. Fetal Developmental Factors: Some normal fetuses may temporarily have weaker amniotic fluid swallowing ability, leading to transient accumulation of amniotic fluid without other abnormalities. This condition usually self-corrects as the fetus develops and is often characterized by mild polyhydramnios. No specific treatment is required; regular ultrasound monitoring of amniotic fluid volume and fetal development is recommended. Pregnant women should ensure adequate rest, avoid strenuous activity, and prevent premature rupture of membranes.

3. Fetal Gastrointestinal Malformations: Gastrointestinal malformations such as esophageal atresia or duodenal atresia prevent the fetus from swallowing amniotic fluid normally, reducing its clearance and causing polyhydramnios, often accompanied by abnormal fetal abdominal findings. These malformations can be detected via ultrasound. After a confirmed diagnosis, fetal prognosis should be evaluated under a physician's guidance. Postnatal surgical correction, such as esophageal anastomosis or duodenal anastomosis, should be promptly performed to restore gastrointestinal function.

4. Fetal Urinary System Malformations: Malformations such as fetal renal hypoplasia or urethral obstruction lead to reduced fetal urine output, disrupting amniotic fluid circulation and causing polyhydramnios, often accompanied by abnormal fetal renal structures. Further diagnostic tests are needed to determine the type of malformation. Severe malformations may require pregnancy termination per medical advice, while treatable malformations may be managed postnatally with procedures such as urethroplasty or nephrostomy to improve urinary system function.

5. Maternal-Fetal Blood Type Incompatibility: For example, ABO incompatibility occurs when maternal antibodies against fetal red blood cells develop, causing fetal hemolysis, resulting in fetal anemia and edema, which may secondarily lead to polyhydramnios along with fetal hepatosplenomegaly. Pregnant women should regularly monitor antibody titers. When titers rise, medications such as Yin Zhi Huang oral liquid, vitamin E soft capsules, and calcium gluconate oral liquid should be used as directed to reduce hemolytic risk. Intrauterine blood transfusion may be necessary to reduce fetal injury.

In daily life, maintaining a regular routine, avoiding fatigue, and attending regular prenatal checkups to promptly detect amniotic fluid abnormalities are recommended. Emotional stability should be maintained, excessive anxiety avoided, and a light, nutritious diet with adequate protein intake followed to provide sufficient nutrition for fetal development and reduce complications.

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The normal fetal position should be cephalic, meaning the fetal head is facing downward with the occiput approaching the maternal pelvic inlet. In contrast, breech position is a type of abnormal fetal presentation. This condition may occur when the fetus has excessive space for movement within the uterus, such as in cases of polyhydramnios, or insufficient space, for example due to uterine malformation or pelvic narrowing, preventing the fetus from normally rotating into a cephalic position.

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What are the symptoms of gestational diabetes?

In general, gestational diabetes refers to diabetes that occurs during pregnancy. Gestational diabetes may be accompanied by symptoms such as excessive thirst, increased appetite, blurred vision, fatigue, and polyhydramnios (excess amniotic fluid). It is recommended to seek medical attention promptly, identify the underlying cause, and receive symptomatic treatment under the guidance of a qualified physician. Pregnant women are advised to maintain a balanced diet during pregnancy and avoid consuming excessive amounts of high-sugar and high-fat foods.

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What to do about a fetus in a transverse position

In general, fetal oblique position may be caused by factors such as不良 living habits, abnormal uterine shape, excessive tension in the abdominal muscles or uterine ligaments, polyhydramnios or oligohydramnios, multiple pregnancies, and so on. It can be improved through general treatment, medication, surgical treatment, and other methods. During pregnancy, pregnant women should maintain a healthy lifestyle and visit the hospital regularly for follow-up examinations.

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What are the causes of polyhydramnios or oligohydramnios?

In general, polyhydramnios (excessive amniotic fluid) or oligohydramnios (insufficient amniotic fluid) may be caused by individual physiological differences, changes in gestational age, gestational diabetes, fetal urinary system malformations, placental dysfunction, and other factors. It is recommended to seek timely medical attention, identify the underlying cause, and undergo symptomatic treatment under a doctor's guidance. Pregnant women should maintain a balanced diet, drink an appropriate amount of water, and avoid either excessive water restriction or excessive water intake.