Polyhydramnios is a medical condition in which an excess of amniotic fluid is present in the amniotic sac. It is seen in about 1% of pregnancies. It is typically diagnosed when amniotic fluid index (AFI) is greater than 24 cm.
Polyhydramnios condition may be of two types:
- Chronic polyhydramnios where excess amniotic fluid accumulates gradually
- Acute polyhydramnios where excess amniotic fluid collects rapidly.
Causes of polyhydramnios may be single or may be multiple and in many cases cause of polyhydramnios may be not known. Some important causes of polyhydramnios are maternal cardiac problems, renal problems, maternal diabetes mellitus, and some viral infection and foetal cause are congenital foetal malformation (tracheao esophageal fistula, anencephaly, open spina bifida, facial cleft and neck masses), twin baby syndrome, Rh blood group incompatibility and chorioangioma of placenta, etc.
In majority of cases the accumulation of amniotic fluid is gradual and the patient is not very much inconvenienced. The patient may suffer from dyspnoea, palpitation, edema of leg, varicosities in the legs or vulva and haemorrhoids.
Investigation by sonography in which AFI is more than 24cm. on the basis of AFI polyhydramnios may be of mild, moderate and severe. If AFI is upto 29cm it is categorised as mild and in between 29 to 35cm it is moderate. When AFI is more than 35cm it is severe type of polyhydramnios. In case of severe polyhydramnios the chance of foetal malformation is more and perinatal mortality rate is high. Radiography is not commonly performed these days.
Polyhydramnios can cause maternal and foetal complication. Maternal complications may be eclampsia, malpresentation, premature rupture of membrane, pre-term labour, accidental haemorrhage, cord prolapse, uterine inertia.
The death of foetus is mostly due to prematurity and congenital abnormality.
Management of polyhydramnios depend on the severity of it. In minor degree amnios usually require no treatment except extra bed rest for few days. In case of severe case of polyhydramnios if there is no foetal abnormality and pregnancy is less than 37 weeks amnio reduction is done.