An unborn baby (fetus) lives in the mother's uterus in a sac of amniotic fluid. This fluid:

  • Protects the fetus from trauma.

  • Helps the fetus move freely inside the uterus.

  • Helps the fetal lungs, kidneys, and digestive system develop.

  • Protects the baby from infections.  

Oligohydramnios is when there is not enough amniotic fluid in the amniotic sac. If this happens early in pregnancy, a fetus might not develop normally. If this happens in the second half of a pregnancy, a fetus might not grow as much as it should and could cause problems during delivery.  

Oligohydramnios can also cause:

  • Pregnancy loss (miscarriage).

  • Premature birth.

  • Deformities of the face or body.

  • Problems with muscles and bones.

  • Pressure and compression on the umbilical cord, which decreases oxygen to the fetus.

  • Lung problems.

  • Stillbirth.


A cause cannot always be found. However, possible causes include:

  • A leak or a tear in the amniotic sac.

  • A problem with the placenta.

  • Having identical twins who share the same placenta.

  • A fetal birth defect. This is usually something in the fetal kidneys or urinary tract that has not developed as it should.

  • A pregnancy that goes past the due date.

  • Something that affects the mother's body, such as:

  • Dehydration.

  • High blood pressure.

  • Diabetes.

  • Some medications (examples include ibuprofen and blood pressure medicines). 

  • A disease that affects the skin, joints, kidneys and other organs (systemic lupus).

  • Birth defects.


  • There may be no symptoms. 

  • Leaking fluid from the vagina.

  • Measuring smaller than usual uterus at a routine pregnancy exam.


To diagnose and evaluate oligohydramnios, your caregiver may:

  • Order a prenatal ultrasound test. This test:

  • Measures the amniotic fluid level. This will show if the amount of fluid is right for the stage of pregnancy.

  • Checks the fetal kidneys.

  • Checks fetal growth.

  • Evaluates the placenta.

  • Confirm that you broke your water, if this is suspected by your caregiver.

  • Order a nonstress test. This noninvasive test is an assessment of fetal well-being. It monitors the fetal heart rate patterns over a 20 minute period.

  • Order a biophysical profile. This test measures and evaluates 5 observations of the baby (results of nonstress testing, fetal breathing, movements, muscle tone, and amount of amniotic fluid).

  • Assess fetal kick counts. Tell your caregiver if the baby appears to become less active.

  • Order a uterine artery doppler study. This is a type of ultrasound. It can show if enough blood and nourishment are getting to the fetus through the placenta and umbilical cord.

  • Check your blood pressure.

  • Check your blood sugar.


Treatment will depend on how low the fluid is, how far along in the pregnancy you are, and your overall health. Treatment options include:

  • Watching and waiting. You will need to be checked more often than normal.

  • Increasing your fluid intake. This may be done by mouth, or you might get the fluids through the vein (intravenously, IV).

  • Delivering the baby if recommended by your caregiver.


  • Only take medicine as directed by your caregiver, especially if you have a medical problem (diabetes, high blood pressure).

  • Follow your caregiver's instructions regarding physical activity, especially if you have a medical problem (diabetes, high blood pressure).

  • Keep all prenatal care appointments.

  • Rest as much as possible. Your caregiver may put you on bed rest.

  • Drink enough fluids to keep your urine clear or pale yellow.

  • Eat a healthy and nourishing diet.

  • Do not smoke, drink alcohol, or take illegal drugs. 


  • You have any questions or worries about your pregnancy.

  • You notice a decrease in fetal movement.


  • Fluid comes out of your vagina.

  • You start to have labor pains (contractions).

  • You have a fever.