What is Polyhydramnios? Symptoms, Causes, and Pregnancy Care

Introduction

Polyhydramnios is a buildup of too much amniotic fluid in the uterus during pregnancy. Usually, mild polyhydramnios does not harm the fetus, but moderate to severe cases require immediate medical attention.

Amniotic fluid acts as a cushion that helps absorb shock from bumps, falls, or pressure on the mother’s abdomen. The baby breathes in and out of the fluid, which helps the lungs grow. In addition, the fluid gives the baby enough space to stretch and kick while allowing the baby to move around and maintain a constant, warm temperature.

However, excessive levels of amniotic fluid can negatively affect pregnancy. When the fluid increases, the uterus becomes overdistended, leading to abdominal discomfort and tightness in the abdomen.

The challenging part is that this increases the risk of preterm labour and causes breathing difficulty for the mother. It also increases the chance of an abnormal foetal position. Hence, it is important to diagnose the condition early and monitor the pregnancy.

What is Polyhydramnios?

Polyhydramnios is a condition in which the amniotic fluid volume exceeds normal limits. This mostly occurs in the second half of pregnancy, but can also occur as early as the 16th week.

The amount of amniotic fluid depends on the stage of pregnancy: at 12 weeks, it is approximately 50-100 ml, and at 32-34 weeks, it is 800-1,000 ml. However, after 34-36 weeks, the amount of amniotic fluid gradually decreases as the delivery date approaches.

Polyhydramnios is classified by the severity of the excess fluid, and is categorised into three main stages -

Healthcare providers diagnose the condition during the third trimester (between 28 and 36 weeks). This is when amniotic fluid reaches its highest level, a finding that can be detected on routine ultrasounds. But, depending on the underlying cause, it can also be diagnosed after 20 weeks. 

What Causes Polyhydramnios?

Here are known causes of polyhydramnios -

• Gestational Diabetes: High blood glucose levels can also cause the amniotic fluid to rise.
• Fetal Conditions: Conditions that may affect the baby’s digestive tract, central nervous system or certain other organs.
• Multiple Pregnancy (Twins or More): Due to twin-to-twin transfusion, where one of the babies receives too much blood, whereas the other receives too little.
• Placental Causes: Abnormalities of the placenta, such as large placental tumours, can increase the blood flow to the foetus. This causes the baby to produce more urine, thereby increasing amniotic fluid.
• Congenital Anomalies: Certain congenital conditions may prevent the foetus from swallowing amniotic fluid.
• Idiopathic Polyhydramnios (No Identifiable Cause): In most cases, the cause is unclear, and this is common with mild conditions.

Severe cases of polyhydramnios can be caused by certain underlying conditions, such as -

• Heart conditions
• Cleft lip and palate
• Abdominal wall defects
• Chromosomal abnormalities
• Skeletal disorders (dwarfism)
• Gastrointestinal blockages (duodenal atresia)
• Central nervous system defects (spina bifida)

Who is at Risk of Developing Polyhydramnios?

• Diabetes During Pregnancy
• Twin-to-Twin Transfusion Syndrome
• Previous Pregnancy with Polyhydramnios
• Certain Fetal Genetic or Structural Conditions
• Maternal Health Conditions

Symptoms of Polyhydramnios

The symptoms of polyhydramnios may vary depending on the severity of the condition. Mild cases may not show symptoms and can only be detected during a routine ultrasound. However, moderate to severe cases can show the following symptoms -

• Rapid increase in abdominal size
• Shortness of breath
• Abdominal tightness or discomfort
• Swelling in the legs and feet
• Difficulty sleeping
• Premature uterine contractions
• Difficulty in feeling foetal movement
• Heartburn
• Peeing more often
• Swelling in the vulva (external genitals)

When the amniotic fluid level increases, it puts pressure on the nearby organs, such as the stomach, bladder, and lungs. This adds pressure to the body and causes the above-mentioned symptoms.

If the healthcare provider feels that the uterus measures larger than expected or fetal parts are difficult to palpate, polyhydramnios may be suspected.

How is Polyhydramnios Diagnosed?

The gynaecologist will measure the abdomen using a measurement called fundal height. This determines if the uterus is too large. Here are some ways the healthcare provider might use to diagnose the condition -

Ultrasound Examination

Ultrasound is performed using two methods to measure the amniotic fluid level in the uterus.

• Amniotic Fluid Index (AFI): AFI is measured to assess how deep the fluid is in the four quadrants (regions) of the uterus. Then the provider adds the numbers to determine the result. 
• Deepest Vertical Pocket (DVP): DVP, commonly known as Single Vertical Pocket or Maximum Vertical Pocket, measures the depth of the largest amniotic fluid pocket, excluding the baby and umbilical cord. 

Depending on the severity of polyhydramnios and the timing, doctors can recommend a few tests to determine the root cause, such as - 

• Blood Tests: These tests are performed to check for infectious diseases that might cause polyhydramnios. 
• Screening for Gestational Diabetes: To check for gestational diabetes, mothers are recommended to undergo a glucose screening test or an oral glucose tolerance test.
• Fetal Assessment: Fetal assessment, also known as a biophysical profile, is performed using ultrasound to encourage fetal movement. Here, doctors assess the baby's breathing pattern and movement, which helps measure the level of amniotic fluid in the uterus; this is usually combined with a nonstress test. 
• Amniocentesis: This is a procedure in which a sample of amniotic fluid is removed using a thin needle under ultrasound guidance. This is done for genetic or chromosomal conditions, fetal infections, and other conditions. 
• Nonstress Test: This test checks how the baby’s heart rate responds to the baby's movements. Patients are given a device called an abdomen to wear on the stomach to conduct the test. If there’s limited movement, a buzzer-like device is also used to wake the baby up and encourage movement. 

The healthcare provider will track and monitor the patient throughout the pregnancy if polyhydramnios is detected. 

How Can Polyhydramnios Affect Pregnancy?

Polyhydramnios poses several risks and complications for both the mother and the foetus, such as -

• Preterm Labour: The excessive fluid in the uterus can cause it to expand, causing premature contractions.
• Premature Rupture of Membranes: Due to increased amniotic fluid, the amniotic sac may rupture before labour begins.
• Abnormal Fetal Position: The excess fluid in the uterus causes the baby to move too freely, which makes it less likely to settle into the head-down position before labour. This results in breech, transverse, and other abnormal foetal positions. 
• Umbilical Cord Prolapse: In cases of severe polyhydramnios, the umbilical cord may slip into the birth canal ahead of the fetus. This can be a life-threatening situation for the foetus.
• Placental Abruption: The placenta might separate from the uterine wall before the due date, which leads to severe bleeding.
• Increased Risk of Cesarean Delivery: Polyhydramnios can increase the risk of cesarean delivery in the event of umbilical cord prolapse.
• Stillbirth: Stillbirth is one of the complications of polyhydramnios, as it can lead to foetal demise.

Does Polyhydramnios Affect the Baby?

Polyhydramnios rarely affects the baby directly. But there are certain ways it can affect the foetus -

• Fetal Growth: Although increased amniotic fluid does not restrict fetal growth, its underlying causes can lead to size abnormalities.
• Congenital Conditions: Excessive amniotic fluid is a warning sign that the baby inside the uterus may have difficulty swallowing or urinating. This may indicate neurological conditions, heart or lung diseases that can impair normal fluid circulation.
• Premature Birth: When amniotic fluid in the uterus increases, the uterus expands. This may trigger early contractions.

After the baby is born, they might experience breathing issues; hence, they are transferred to the Neonatal Intensive Care Unit (NICU) for monitoring and treatment.

Treatment and Pregnancy Care

Polyhydramnios rarely needs treatment and may go away on its own. However, if it is linked to any underlying condition, then treatment becomes necessary.

Regular Prenatal Monitoring

Regular prenatal monitoring is required to monitor maternal health. It helps detect any complications associated with polyhydramnios. This ensures the best possible outcomes for pregnancy.

Managing the Underlying Cause

Certain underlying conditions, such as gestational diabetes, Rh incompatibility, pulmonary cysts, foetal or placental tumour, etc., should be managed effectively. When done correctly, it may reduce the fluid level.

Medications (When Appropriate)

The healthcare professional may prescribe oral medication. It is used for 48 hours to help reduce contractions and amniotic fluid volume. Always talk about any possible side effects before taking the medicine.

Amnioreduction (Selected Cases)

Amnioreduction is only advised in cases of severe polyhydramnios. It is a procedure done to drain large amounts of excess amniotic fluid. This procedure reduces the risk of preterm birth, cord prolapse, and placental abruption.

Fetal Well-Being Assessments

As polyhydramnios is associated with a higher risk of stillbirth, it is recommended to get a fetal assessment. Methods used for fetal surveillance include.

• Non-Stress Test
• Biophysical Profile
• Contraction Stress Test
• Umbilical Artery Doppler Velocimetry

Note: After the treatment, the healthcare professional will ask the patient to return for an amniotic fluid level check.

Lifestyle Tips During Pregnancy

Lifestyle also helps women to have a healthy pregnancy. Some factors to consider to avoid complications are -

Attend All Prenatal Appointments

Visit the doctor's clinic for all prenatal appointments. Regular visits and checkups help ensure that the baby is doing well. It also helps detect any complications early, so that treatment plans can be charted accordingly.

Monitor Fetal Movements

Foetal movements should also be monitored daily to understand and check the position of the fetus in the womb. It also helps recognise potential early warning signs of foetal distress, such as low oxygen levels or placental insufficiency.

Eat a Balanced Diet

The eating plan in pregnancy consists of healthy food and low-calorie beverages, specifically water. This is beneficial for the mother and baby to gain the proper amount of weight.

Factors affecting the amount of food and calories include weight before pregnancy, age, and how quickly you gain weight. According to the CDC, if the patient is at a healthy weight, no extra calories are required in the first trimester, 340 extra calories per day in the second trimester, and 450 extra calories per day in the third trimester.

Manage Blood Sugar Levels (If You Have Diabetes)

Managing blood sugar can reduce fluid and lower the risk of preterm labour. The glucose in the mother’s body causes the baby to produce excess urine, which leads to excess amniotic fluid.

Stay Hydrated

Drinking plenty of water throughout the day during pregnancy helps maintain adequate blood volume and prevent dehydration or overheating.

Get Adequate Rest

Sleep for at least 6-9 hours every night. It is also important to manage stress and anxiety through mindfulness or meditation.

Polyhydramnios and Delivery Planning

Can Polyhydramnios Be Prevented?

Polyhydramnios cannot be completely prevented. However, patients can take certain precautions to manage their existing condition, such as diabetes (which can be gestational or the mother might have diabetes before becoming pregnant).

Here are some tips to follow to manage polyhydramnios - 

• Managing diabetes before and during pregnancy
• Regular prenatal care
• Early detection through routine ultrasounds
• Following medical advice for high-risk pregnancies
• Maintain good hygiene, as it can reduce the risk of infections during pregnancy

Doctors also advise getting proper vaccinations. This may prevent infections that may contribute to polyhydramnios.

However, if the patient is diagnosed with polyhydramnios, then here’s what they can do to relieve symptoms -

• Find ways to relax and manage stress.
• Take ample rest with a proper sleeping schedule.
• Consult a gynaecologist about the condition. They support patients and ensure the mother and foetus are healthy.

When Should You Contact Your Doctor?

Patients are advised to see a doctor immediately if they experience any of the following symptoms -

• Leaking fluid
• Vaginal bleeding
• Regular contractions before term
• Difficulty breathing, which might feel like not getting enough air
• Reduced fetal movements, which can be a sign of distress for the baby
• A sudden increase in abdominal size that might be discomforting for the pregnant woman

It is important to see a doctor whenever the patient feels an enlargement of the uterus. This is because the large uterus puts pressure on the nearby organs, which may cause the symptoms.

Note: The healthcare professional closely monitors patients with polyhydramnios throughout pregnancy. They might call in the patient for additional ultrasounds to measure and monitor the amniotic fluid. If required, they will suggest necessary treatment options to manage the condition.

Conclusion

Polyhydramnios is a condition that occurs when the amniotic fluid rises above the normal level, causing the uterus to expand more than normal. This might lead to several risks and complications that may be harmful to the baby and mother. Hence, it needs immediate diagnosis and care.

Mild cases do not require interventions, but moderate and severe cases require comprehensive management under close supervision, including frequent monitoring, medical interventions, and sometimes early delivery.

Pregnancy varies from person to person, so it's important to discuss the condition, treatment options, and possible outcomes with the doctor. This helps the expectant mother to understand the complications of polyhydramnios and ensures the best result for the pregnancy.