advice

polyhydramnios in pregnancy:
what is it?

Polyhydramnios occurs when too much amniotic fluid surrounds the fetus in the womb. This excess amniotic fluid can sometimes increase the risk of complicatitons during pregnancy. Learn more about the symptoms, causes and treatments of polyhydramnios below.

what is polyhydramnios?

Amniotic fluid is a helpful cushion created by your body to protect your baby from any bumps or infections, but sometimes your body can create too much of it. This is called polyhydramnios – a common complication that can be detected by your midwife after 30 weeks of pregnancy.


Between 30 and 36 weeks, it’s completely normal your amniotic fluid to increase to between 800 and 1,000 ml. Then in those final weeks the volume of amniotic fluid decreases to prepare for the birth. However, if you are experiencing polyhydramnios, the amniotic sac may contain up to 3,000 ml of fluid.


This may sound like a lot, but the vast majority of mums-to-be who experience polyhydramnios go on to have totally uncomplicated births and healthy babies, so it's just something to be aware of and keep an eye on.

what are the symptoms of polyhydramnios?

If you notice your pregnant tummy is getting quite big quicker than expected, then you may be experiencing acute polyhydramnios. It's always best to contact your midwife or doctor to see whether this is the case and receive expert advice. They may be able to detect the build-up after 18 to 22 weeks.


For most women who have the complication, however, the amniotic fluid builds up slowly – which is why the 30-week mark arrives before it’s detected. If more amniotic fluid than usual is suspected, it’s likely that you’ll be booked in for an additional ultrasound scan, so that they can measure its depth.


Another symptom to watch out for is shiny, stretched skin on your bump, and you may find that you get out of breath more easily.


Polyhydramnios can also aggravate these common pregnancy symptoms (which is why the condition is a little difficult to self-diagnose):


  • constipation
  • heartburn
  • varicose veins
  • indigestion
  • stretch marks
  • swollen legs

causes of polyhydramnios

The reasons why some pregnant women develop polyhydramnios are uncertain. However, the complication has been linked to the following:


  • being pregnant with twins
  • your unborn baby having a gut atresia, a small blockage in their developing digestive system
  • having diabetes
  • a genetic issue with your unborn child
  • a chorioangioma, or too many blood vessels on the placenta
  • having rhesus disease, which can result in your unborn baby becoming anaemic
  • hydrops fetalis, or fluid building up in certain parts of your unborn baby’s body – namely the chest cavity and abdomen

how is polyhydramnios treated?

While pregnant women with polyhydramnios may be prescribed medication, doctors and midwives usually recommend taking lots of rest and to avoid doing anything that may cause breathlessness.


Only mums-to-be with particularly severe polyhydramnios will need to have some of their excess amniotic fluid drained, which will reduce the likelihood of a premature birth and the onset of potential placenta problems. If such a procedure is necessary then new mums may be advised to take maternity leave early, as they’ll need to take more rest than normal.


If your doctor is able to identify a particular cause behind your polyhydramnios, then they’ll certainly provide an additional care plan to ensure that your recovery, and your baby's, is a speedy one.