Polyhydramnios is a condition of accumulation of excessive amniotic fluid (exceeds 2000 ml) surrounding the foetus causing discomfort to the pregnant woman.
Amniotic fluid surrounds the foetus during pregnancy. The normal is 500 to 800 ml at term. Excessive accumulation of amniotic fluid occurs in 1 to 2% of cases.
It is more common in women with second or third pregnancies than with first pregnancy. A minor degree of polyhydramnios are quite common but severe polyhydramnios can produce severe symptoms that occur in 1 in 1000 pregnancies.
Causes
The exact cause of excessive accumulation of the amniotic fluid is not clear. It may be the result of decreased absorption as well as excessive production of the fluid. While certain factors are found to be associated with polyhydramnios.
- Twin pregnancy
- Diabetes mellitus
- Congenital fetal malformations (especially the central nervous system and gastrointestinal system) are associated with polyhydramnios such as anencephaly, open spina bifida, facial clefts
- Maternal infections
- Blood incompatibilities
- Chorioangioma (tumour of the villus) of the placenta
Types of polyhydramnios
Depending on the onset, polyhydramnios maybe
- Acute polyhydramnios- Very rare and sudden in onset; develop within few days. It usually develops very rapidly around the fourth month of pregnancy and causes rapid enlargement of the abdomen more than 100 cm.
- Chronic polyhydramnios- Very common and take a few weeks to develop during the second half of pregnancy (30 weeks).
Symptoms
A mild form of polyhydramnios does not cause many symptoms and go away on its own but severe polyhydramnios may cause symptoms such as
- Severe shortness of breath
- Severe abdominal discomfort
- Swelling of the abdomen and legs
- Difficult to palpate fetal parts
- Fetal heart sound not audible
- Abdominal girth more than 100 cm
- Fetal malpresentation such as breech
- Varicose vein
Diagnosis
When you are experiencing the symptoms of polyhydramnios, your healthcare provider may carry out some tests which may include-
Ultrasonography- High-frequency sound waves are used to produce images of your baby on a monitor. It’s helpful to detect abnormally large echo-free space between the foetus and the uterine wall; to know the lie and presentation of the foetus; to diagnose any foetal congenital malformation.
Amniotic fluid index (AFI) is measured by measuring the largest pocket in four specific parts of your uterus. The sum of these measurements is the amniotic fluid index. An AFI of more than 25 cm indicates polyhydramnios.
Blood studies may include ABO and Rh grouping; glucose tolerance tests for diabetes.
Estimation of Alpha fetoprotein– It is elevated in the presence of a foetus with an open neural tube defect.
Complications
Complications may include
- Pre-eclampsia
- Malpresentation
- Premature rupture of the membranes
- Preterm labour
- Cord prolapse
- Inadequate uterine contractions during labour
- Increased chance of operative delivery due to malpresentation
- Retained placenta
- Postpartum hemorrhage due to inadequate uterine contractions
- Subinvolution
- Fetal death due to congenital abnormality
Treatment
In the case of minor polyhydramnios, which is commonly found in the second half of pregnancy usually requires no treatment and may go on their own; except for extra bed rest for a few days. The excess amniotic fluid is expected to be reduced as pregnancy advances.
Treatment for underlying conditions such as diabetes and infections may help to resolve polyhydramnios.
In uncomplicated cases with no fetal malformations and response to the treatment is good, the pregnancy is to be continued awaiting spontaneous delivery at term. To relieve the distress, slow decompression has to be done through drainage of excessive amniotic fluid by amniocentesis procedure. Indomethacin medication can be given orally to decrease amniotic fluid.
In case of severe polyhydramnios with maternal distress, your doctor may discuss the appropriate time for termination of pregnancy to avoid complications for you and your baby.
In the case of a foetus with a congenital abnormality, termination of pregnancy is to be done irrespective of the duration of pregnancy.
Conclusion
In the above post, we have discussed polyhydramnios. Polyhydramnios is an excessive accumulation of amniotic fluid surrounding the foetus which causes discomfort to the mother. It results from excessive production and inadequate absorption of the fluid due to certain factors. Shortness of breath, abdominal discomfort, swelling of legs are some of the symptoms. It can be diagnosed by ultrasonography and blood studies. Minor polyhydramnios doesn’t require any treatment. Other cases can be treated by drainage of excessive amniotic fluid and using indomethacin medication.
