Polyhydramnios Definition

Polyhydramnios is an abnormal condition occurring in pregnancy, characterized by excessive amniotic fluid build-up (the fluid surrounding the baby in the uterus) [1].  It is the opposite of oligohydramnios (extremely low amniotic fluid levels). Apart from protecting the baby from any external impact by providing a cushioning effect, the clear or slightly yellowish fluid plays a vital role in proper fetal development as well. But, increased levels of the fluid can cause various complications during different stages of pregnancy and childbirth.

Polyhydramnios High Amniotic Fluid Pictures

Polyhydramnios Classification

1.) Chronic polyhydramnios: Characterized by gradual accumulation of amniotic fluid
2.) Acute polyhydramnios: Characterized by sudden and rapid accumulation of amniotic fluid

What Causes Polyhydramnios?

Around 50% of the cases are idiopathic [2], with experts still trying to find out the responsible causes. The known causes and risk factors include:

Fetal Causes

  • Fetal Abnormalities [2]: Fetal anomalies such as hydrocephaly, anencephaly, esophageal atresia, fetal kidney problems, duodenal atresia, tracheoesophageal fistula, skeletal dysplasias, spina bifida and diaphragmatic hernia that can hamper the baby’s ability of swallowing and processing the amniotic fluid properly
  • Fetal Anemia: RBC (red blood cells) deficiency in the baby
  • Hydrops Fetalis (fluid accumulation or edema in two or more fetal compartments)
  • Chromosomal Abnormalities [3]: Inheriting abnormal chromosomes responsible for genetic disorders like Down’s syndrome and Edwards’ syndrome
  • Fetal macrosomia (having a baby too large for the gestational age)

Placental Causes

  • Twin-to-Twin Transfusion [4]: An abnormal condition occurring when carrying identical twins, in which one twin receives excessive amounts of amniotic fluid while the other has little
  • Placental Blood Vessel Abnormality: Abnormal blood vessel growth on the placenta (chorioangioma) [5]

Maternal Causes

  • Infectious Conditions: Toxoplasmosis [2], parvovirus, herpes simplex, rubella or cytomegalovirus infections affecting the mother may also reach the fetus, causing various abnormalities
  • Maternal Diabetes Mellitus (gestational or pre-existing): Abnormal blood sugar levels in the mother may lead the baby to produce excessive urine that increases the amniotic fluid volume [3]
  • Maternal Rhesus Disease: Rhesus disease causes the mother’s antibodies to cross the placenta, often resulting in fetal anemia – one of the principal causes of Polyhydramnios
  • Blood incompatibilities between the mother and the baby [4]
  • Hypertension
  • Pre-eclampsia

What are the Symptoms of Polyhydramnios?

Mild cases of polyhydramnios may not cause any noticeable signs in the mother [6]. However, severe cases can lead to the following symptoms:

  • Difficulty breathing unless standing or sitting in an upright position [7]
  • Difficulty climbing stairs
  • Decreased urine production
  • Larger belly size for one’s gestational age
  • Swelling of the abdominal wall, vulva and legs
  • Excessive weight gain [13]

Polyhydramnios may be suspected by the doctor in case it seems difficult to assess the body contours and heart beat of the baby despite an enlarged size of the uterus. Excessive amounts of amniotic fluid in the uterus tend to worsen certain pregnancy symptoms, such as:

  • Indigestion [3]
  • Constipation
  • Abdominal pain
  • Heartburn
  • Stretch marks
  • Varicose veins [3] (when the valves within the veins stop working, causing the venous walls to become weak, leading to blood accumulation in the weak spots)

What Problems are Likely to Result from Polyhydramnios?

  • Preterm Labor or Premature Birth [8]: Delivery before completing the 37th week of pregnancy
  • Placental Abruption: An abnormal condition characterized by partial or complete peeling away of placenta from the uterus wall before the baby is born
  • Premature Rupture of Membranes (PROM): Breakage or tearing of the amniotic sac after the 37th week of pregnancy but prior to the onset of labor
  • Birth Defects (Down’s syndrome, cleft palate)
  • Stillbirth: Death of the baby in the uterus after the 20th week of pregnancy
  • Fetal Malposition [1]: The baby lying in an atypical head-down position, often calling for a c-section delivery
  • Excessive fetal growth

Polyhydramnios Diagnosis and Diagnostic Criteria

The principal diagnostic criterion is an amniotic fluid index (AFI) over 24 cm shown on ultrasound findings [9]. The higher the amniotic fluid index, the graver the condition is.

Fetal Ultrasound

A detailed ultrasound [10] may be ordered to estimate the amniotic fluid levels by assessing the deepest pockets in four particular regions of the uterus. These measurements are then used for determining the AFI.

Polyhydramnios Ultrasound Picture

Polyhydramnios Ultrasound Picture


A fetal ultrasound is also useful for making the differential diagnosis by ruling out certain complications and birth defects.


This diagnostic procedure involves collecting an amniotic fluid sample (containing fetal cells and fetus produced chemicals) and testing it in a laboratory for evidences of any infections or other abnormalities.

Glucose Challenge Test

This test is performed to find out if the mother is suffering from gestational diabetes, which can confirm the diagnosis of Polyhydramnios.


It is a screening test, often used for checking the chromosomes of the baby for abnormalities. Cell samples can be collected from the placenta or the amniotic fluid sample during amniocentesis (extracting amniotic fluid by centesis for diagnostic purposes).

Polyhydramnios Differential Diagnosis

  • Abruptio placenta [9] (Placental Abruption)
  • Chorioangioma

Tests for Monitoring and Managing Polyhydramnios

Women diagnosed with polyhydramnios are generally monitored closely for measuring the amniotic fluid levels and for ensuring proper growth and health of their babies. Certain tests and procedures, such as amniocentesis and weekly ultrasounds, are commonly used for management and monitoring of the fetal abnormalities responsible for the high fluid levels. The following tests are also used for assessing the baby’s heart rate, breathing, movements and circulation:

  • Non-Stress Test
  • Biophysical Profile (diagnostic procedure that combines the non-stress test with an ultrasound)
  • Doppler Ultrasound [10]
  • Fetal Echocardiogram
  • Contraction Stress Test (assessing the baby’s heart rate with contraction of the uterus)
  • Blood Tests (for monitoring the mother’s diabetes levels)

Polyhydramnios Treatment

No treatment is necessary for the mother unless acute symptoms of polyhydramnios are present. [11] Women experiencing preterm labor, severe abdominal pain and shortness of breath may even need early hospitalization. The treatment procedure may be similar to that used for managing the twin-to-twin transfusion syndrome.

Drugs and Medications

An oral medication named Indocin (indomethacin) [11] is often prescribed as it helps to reduce the fetal urine production, keeping the amniotic fluid levels in check. However, it is not recommended after the 31st week of pregnancy. In some cases, the doctor may prescribe medicines for stabilizing the baby’s heart rate [1]. Possible side effects of the drugs include vomiting, nausea, acid reflux and gastritis.

Draining Excess Fluid

Sometimes, the amnioreduction procedure is used for draining the excess amniotic fluid from the uterus. Multiple sessions of amnioreduction may be necessary for keeping the fluid levels normal with the progression of pregnancy. [11]

How to Cope With Polyhydramnios?

  • Complete bed rest [9], especially towards the later pregnancy stages
  • Avoiding eating large meals
  • Avoiding any jerky movements
  • Using pillows and cushions for supporting the belly in bed
  • Avoiding spicy foods and any other foods that tend to worsen the heartburn [12]
  • Avoiding lying down immediately after eating
  • Taking regular antenatal classes for polyhydramnios management guidelines

Polyhydramnios Complications

  • Postpartum Hemorrhage: Extreme bleeding after delivery due to decreased uterine muscle tone
  • High blood pressure (pregnancy-induced)
  • Urinary tract infections in pregnancy
  • Umbilical cord prolapse (umbilical cord dropping into the vagina in front of the baby)
  • Placental Abruption
  • Premature rupture of the membranes

Polyhydramnios Prognosis

Mild cases of polyhydramnios generally have a positive prognosis with natural birth of a healthy baby. Minor abnormalities in the newborn can be monitored and corrected after birth. Polyhydramnios resulting from some fetal and placental malformations is likely to have a poor prognosis with the associated mortality rate being around 61%. [9] Its chances of recurrence are quite low for future pregnancies.

Polyhydramnios ICD-9 and ICD-10 Codes

The ICD-9 code of Polyhydramnios is 657 while its ICD-10 code is O40.

Polyhydramnios Support

March of Dimes National Office

1275 Mamaroneck Avenue

White Plains, New York State 10605

Phone: (914) 997-4488

Website: http://www.marchofdimes.com/index.aspx

  1. www.marchofdimes.com/pregnancy/polyhydramnios.aspx
  2. https://www.clinicalkey.com/topics/obstetrics-gynecology/polyhydramnios.html
  3. http://www.babycentre.co.uk/a551936/polyhydramnios
  4. http://www.mayoclinic.com/health/polyhydramnios/DS01156/DSECTION=causes
  5. http://www.nhs.uk/conditions/polyhydramnios/Pages/polyhydramnios.aspx
  6. http://pregnant.thebump.com/pregnancy/pregnancy-problems/articles/polyhydramnios.aspx?MsdVisit=1
  7. http://www.mayoclinic.com/health/polyhydramnios/DS01156/DSECTION=symptoms
  8. http://www.mayoclinic.com/health/polyhydramnios/DS01156/DSECTION=complications
  9. http://www.patient.co.uk/doctor/polyhydramnios
  10. http://www.mayoclinic.com/health/polyhydramnios/DS01156/DSECTION=tests-and-diagnosis
  11. http://www.mayoclinic.com/health/polyhydramnios/DS01156/DSECTION=treatments-and-drugs
  12. http://www.babycenter.in/a551936/polyhydramnios
  13. http://www.huggies.com.au/pregnancy/complications/polyhydramnios/ [/ref]