Treatment and Monitoring

There is no treatment for Polyhydramnios, but there are ways to manage the condition. There are also guidelines that should be followed for proper monitoring of pregnancies complicated by Polyhydramnios. Monitoring and management methods include management of the underlying condition (when possible), fetal surveillance, reducing fluid, and creating an effective care plan. 

Table of Contents

Treatment

Treatment of Underlying Conditions

Certain underlying conditions that are known to cause Polyhydramnios can be managed effectively and may reduce the level of fluid when done correctly.

Examples include:

  •  Maternal Diabetes can be managed with good glycemic control, either by diet and exercise, medication, insulin injections, or a combination of all of these
  • Rh incompatibility can be managed with RHOGAM injections if alloimmunization has not occurred
  • Certain infections can be managed with antibiotics or other medications
  • Hydrops caused by fetal anemia can be managed by close monitoring and intrauterine blood transfusions
  • Hydrops caused by heart arrhythmias can sometimes be controlled by antiarrhythmic medication
  • Pulmonary cysts or pleural effusions can be treated by thoracoamniotic shunting
  • Twin to twin transfusion syndrome and fetal or placental tumors can be managed with laser occlusion

Monitoring

Recommended Types of Fetal Surveillance

The ACOG recommends antenatal surveillance in all pregnancies at risk for stillbirth beginning at 32 weeks. However, the Society for Maternal-Fetal Medicine (SMFM) has stated that fetal surveillance is not required in cases of mild, idiopathic Polyhydramnios.

*Because Polyhydramnios is associated with a higher risk of stillbirth, we recommend fetal surveillance should be used in all pregnancies complicated by persistent Polyhydramnios in order to monitor for signs of fetal distress. 

Methods for fetal surveillance include:

  •  Contraction Stress Test (CST)
  • Non-Stress Test (NST)
  • Biophysical Profile (BPP)
  • Modified Biophysical Profile (Modified BPP)
  • Umbilical Artery Doppler Velocimetry (only in cases complicated by IUGR)

Mild Idiopathic Polyhydramnios

  • Fetal surveillance every other week beginning at 32 weeks
  • Fetal surveillance weekly beginning at 37 weeks 
  • Continue surveillance as long as Polyhydramnios persists, until delivery

Testing to rule out underlying factors should include:

  • Growth scan to check for anomalies, head circumference, abdominal circumference, size, and weight of the baby
  • Glucose tolerance test
  • Rhesus factor screen
  • Rh antibody test if it’s been more than four weeks since the last test for Rh-negative mothers
  • If hydrops is observed, evaluation for fetal anemia and infection

Moderate/Severe Idiopathic Polyhydramnios

  • Fetal surveillance weekly beginning at 32 weeks
  • Continue surveillance as long as Polyhydramnios persists, until delivery

Testing to rule out underlying factors should include:

  • Growth scan to check for anomalies, head circumference, abdominal circumference, size, and weight of the baby
  • Glucose tolerance test
  • Rhesus factor screen
  • Rh antibody test if it’s been more than four weeks since the last test for Rh-negative mothers
  • If hydrops is observed, evaluation for fetal anemia and infection

Early Onset of Polyhydramnios or Polyhydramnios with other High-Risk Factors Present

  • Consider concerning
  • Refer to high-risk and genetic specialists
  • Fetal surveillance beginning as early as 26 weeks
  • Continue surveillance twice weekly until delivery
  • Consider amnioreduction if maternal breathing is severely impacted
 

Testing to rule out underlying factors should include:

  • Growth scan to check for anomalies, head circumference, abdominal circumference, size, and weight of the baby
  • Glucose tolerance test
  • Rhesus factor screen
  • Rh antibody test if it’s been more than four weeks since the last test for Rh-negative mothers
  • If hydrops is observed, evaluation for fetal anemia and infection
  • Fetal echocardiogram to check for heart conditions in the baby
  • Karyotyping and microarray to check for chromosomal changes if ultrasound has detected an anomaly, if fetal growth restriction is present, or if Polyhydramnios has been detected before 24 weeks gestation
  • We recommend additional Whole Exome Sequencing for every baby who has negative karyotype and microarray results

Reducing Fluid

Reducing amniotic fluid is a temporary solution used to either provide relief from the symptoms of Polyhydramnios or to help prolong a pregnancy at risk of preterm delivery.

 

There are two medically recognized methods to reduce amniotic fluid during pregnancy: amnioreduction (not to be confused with amniocentesis) and Prostaglandin Synthetase Inhibitors, such as Indomethacin.

 

Amnioreduction is considered safe to use in extreme circumstances. Indomethacin on the other hand is NOT RECOMMENDED to be used solely for the purpose of reducing fluid because it can harm your baby.

Amnioreduction

*Amnioreduction is only recommended in cases of severe Polyhydramnios (SDP >16 cm or AFI >35.1 cm) where maternal breathing is also severely impacted.

An amnioreduction is a procedure used to drain large amounts of excess amniotic fluid. Don’t confuse it with amniocentesis, which is a procedure used to draw out a small amount of amniotic fluid to be used for testing. Sometimes, amniocentesis may be performed along with an amnioreduction.

Amnioreduction is done for the purpose of 

  • providing maternal relief from the symptoms of severe Polyhydramnios, and 
  • to help reduce the risk of preterm birth

Amnioreduction is done in a hospital setting. A local anesthetic will be given, then, guided by ultrasound, an experienced healthcare provider guides a spinal needle through the abdomen into the uterine cavity. Fluid can be extracted manually or using vacuum suction. The amount of fluid removed will be determined on a case-by-case basis, but it is usually not more than 2500 mL per procedure. Patients are closely monitored during and after amnioreduction for up to 48 hours for signs of preterm labor and placental abruption. The fluid removed during amnioreduction can be used for genetic testing to help determine if there is a genetic anomaly in the baby. This can be very useful to determine a plan for supportive care of both mother and infant. 

In some cases of very severe Polyhydramnios, performing an amnioreduction in early labor may help to prevent poor outcomes such as cord prolapse and placental abruption.

Amnioreduction is not a long-term treatment. The effects of amnioreduction only last a few weeks at the most because it does not treat the underlying condition causing the Polyhydramnios. It is only used to provide relief to symptomatic mothers and to attempt to prolong the pregnancy.

The risks of amnioreduction include:

  • Pain during the procedure
  • Increased contractions
  • Premature labor/birth
  • Spontaneous rupture of membranes
  • Placental abruption (caused by rapid reduction of fluid)
  • Chorioamnionitis (infection of fetal membranes)
  • Stillbirth
 
Amnioreduction has not been well studied in the setting of Polyhydramnios in singleton pregnancies, but a recent study done in Australia showed
  • The average time between the first drain and delivery was 3.7 weeks
  • The rate of PPROM within 48 hours was 1.1%
  • The rate of delivery within 48 hours was 4.1%
  • The rate of fetal death within 24 hours was 0.4% 
Another smaller study published in a 2019 edition of the European Journal of Obstetrics & Gynecology and Reproductive Biology found that among singleton pregnancies undergoing amnioreduction alone, there were
  • No instances of PPROM within the first 12 hours
  • No instances of placental abruption within the first 12 hours
  • No instances of chorioamnionitis within the first 12 hours
  • No instances of preterm delivery within the first 12 hours
  • The rate of preterm delivery within 48 hours was 10.6%

 The conclusions from these studies were

1. Amnioreduction in singleton pregnancies complicated by Polyhydramnios carries a relatively low risk.

2. Amnioreduction may be very useful to prolong certain pregnancies where the baby is expected to undergo surgery shortly after birth. Prolonging labor in these instances greatly improves the outcome for these babies. Read the entire study here.

Prostaglandin Synthetase Inhibitors

The most  commonly used prostaglandin inhibitor is called Indomethacin and its primary medical use is to delay preterm labor for up to 48 hours so that other interventions, such as steroid injections, can be administered. One of the side effects of Indomethacin is that it reduces amniotic fluid levels.
 
*Although indomethacin does reduce the amount of amniotic fluid surrounding a baby, the Society for Maternal-Fetal Medicine recommends that indomethacin NOT be used for the sole purpose of reducing amniotic fluid in the setting of Polyhydramnios.
 
Here’s why:
 
In utero, a baby’s lungs are filled with amniotic fluid. So instead of using its lungs to oxygenate the blood, the placenta oxygenates the blood while in utero. To make this happen, a fetus has an extra blood vessel, called the ductus arteriosus, that works like a shunt to direct blood flow through the baby’s body. Shortly after birth, when a baby starts to breathe on its own, the ductus arteriosus is no longer needed so it closes.
 
Prostaglandin inhibitors used for longer than 48 hours, or after 28 weeks gestation, can cause early closure of the ductus arteriosus. If the ductus arteriosus closes while a baby is still in utero, it leads to reduced blood flow to the kidneys and results in reduced fetal urine output. This reduced urine output is what leads to lower amniotic fluid levels. Unfortunately, the early closure of the ductus arteriosus has also been known to cause major heart problems for babies after delivery.
 
Other risks of indomethacin to a fetus include:
  • bleeding in the heart
  • high blood pressure
  • kidney problems
  • jaundice
  • intestinal illness
  • bleeding in the brain
  • brain injury
 
If Indomethacin is used, it should only be before 28 weeks gestation, for no longer than 24 hours, and for the purpose of stalling premature labor long enough to administer steroid injections to the baby. Indomethacin should never be used for the sole purpose of reducing amniotic fluid.

FAQs

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Read Next

Labor & Delivery – Recommended delivery guidelines for mild, moderate, and severe Polyhydramnios, both idiopathic and with known maternal or fetal complications.

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