What is polyhydramnios?
Polyhydramnios means there is too much amniotic fluid (the fluid around your baby) during pregnancy. Severe polyhydramnios is when the fluid level is much higher than normal. It can cause discomfort and may affect your baby’s position or increase the risk of early labour.
It is diagnosed with an ultrasound scan that measures the depth of amniotic fluid around your baby. It may be found during a routine scan or if you are experiencing symptoms such as a large bump, breathlessness, or early contractions.
Often, no cause is found. When a cause is identified, it may include:
Diabetes in pregnancy
Problems with the baby swallowing or processing fluid
Twin-to-twin transfusion syndrome (in identical twins)
Infections or genetic conditions
Most babies are healthy, especially when no cause is found. In some cases, polyhydramnios can increase the risk of early birth or complications during labour. Your baby will be monitored with extra scans and tests if needed. There is a slightly increased risk of:
Preterm labour (<37 weeks)
Waters breaking prematurely (PPROM)
Postpartum haemorrhage (because the womb is more stretched than usual and may not tighten well after birth)
Placental abruption (placenta coming away from the wall of the womb) can happen if the waters break quickly
Varying positions of the baby (breech, transverse, unstable lie) due to excess fluid which can affect the plan for labour and birth
Cord prolapse
You may have more frequent scans and tests for diabetes or infections. If the fluid is very high, a procedure called amniodrainage may be considered to relieve symptoms. Delivery planning may also be discussed.
If no cause is found, the chance of it happening again is low. If it was related to diabetes or a twin pregnancy, there may be a higher risk in similar future pregnancies.