Polyhydramnios is an abnormal condition occurring in pregnancy, characterized by excessive amniotic fluid build-up (the fluid surrounding the baby in the uterus) . 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.
1.) Chronic polyhydramnios: Characterized by gradual accumulation of amniotic fluid
2.) Acute polyhydramnios: Characterized by sudden and rapid accumulation of amniotic fluid
Around 50% of the cases are idiopathic , with experts still trying to find out the responsible causes. The known causes and risk factors include:
Mild cases of polyhydramnios may not cause any noticeable signs in the mother . However, severe cases can lead to the following symptoms:
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:
The principal diagnostic criterion is an amniotic fluid index (AFI) over 24 cm shown on ultrasound findings . The higher the amniotic fluid index, the graver the condition is.
A detailed ultrasound  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.
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.
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).
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:
No treatment is necessary for the mother unless acute symptoms of polyhydramnios are present.  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.
An oral medication named Indocin (indomethacin)  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 . Possible side effects of the drugs include vomiting, nausea, acid reflux and gastritis.
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. 
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%.  Its chances of recurrence are quite low for future pregnancies.
The ICD-9 code of Polyhydramnios is 657 while its ICD-10 code is O40.
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