Amniotic fluid is a clear to slightly yellow liquid that cushions a fetus within the amniotic sac.
The developing fetus floats in amniotic fluid for the duration of a pregnancy.
At around 34 weeks gestation, roughly 800 milliliters (mL) of amniotic fluid surround the fetus.
Kemal Yildirim / Getty Images
At a full-term pregnancy of 40 weeks gestation, roughly 600 mL of amniotic fluid remain.
Kemal Yildirim / Getty Images
Development
Amniotic fluid is present at the formation of the amniotic sac.
This is a thin-walled sac that contains the fetus during pregnancy.
The remaining 2% is made up of lipids and hormones.
Oligohydramnios
Oligohydramnios shows up when there is too little amniotic fluid surrounding the fetus during pregnancy.
This occurs in about 4% of pregnancies.
Too little amniotic fluid can cause problems with the development of the fetus as well as pregnancy complications.
Too little amniotic fluid can lead to abnormal development of the lungs.
Oligohydramnios can occur for a number of reasons.
A healthcare provider will be able to provide a conclusive diagnosis.
Possible symptoms include:
Oligohydramnios may be diagnosed following an ultrasound.
When this happens, the uterus is much larger than normal.
This is a rare condition, occurring in roughly 1% of pregnancies.
Possible symptoms of polyhydramnios include:
With most pregnancies, the exact cause of polyhydramnios is unknown.
Moderate to severe cases may be because of:
Treatment is often not necessary in mild cases.
Additional appointments may be useful to monitor the growth of the uterus.
Other options include inducing labor early.
A Word From Verywell
Amniotic fluid surrounds the fetus during pregnancy and serves an important function.
It protects the fetus from harm and allows for healthy development.
Complications can occur when there is too much or too little amniotic fluid.
If you are concerned about your pregnancy, you should speak with your healthcare provider.
Johns Hopkins Medicine.Anatomy: fetus in utero.
