Definition
Oligohydramnios is a lower than normal level of amniotic fluid. This fluid supports and protects the baby. It also important for the growth of the baby. Low levels of this fluid can lead to problems for the baby and mother.
Oligohydramnios in the first half of pregnancy may cause:
- Miscarriage
- Compression of the baby, leading to birth defects
- Poor or no lung development
Oligohydramnios in the second half of pregnancy may cause:
- Growth problems for the baby
- Early birth
- Distress for the baby during labor—may lead to cesarean section
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Causes
There are many known causes. Sometimes the exact cause may not be found.
Conditions that can cause oligohydramnios include:
- Birth defects
- Problems with the fetus's urinary system
- A problem with the placenta
- Tear in the amniotic sac
- Pregnancy continuing past the due date
- Problems in the mother, such as dehydration, diabetes, or high blood pressure
- Complications of certain medications
Risk Factors
Factors that increase the chance of getting oligohydramnios include:
- Pregnancy past the due date
- Health problems in the mother
- Development problems in the baby
Symptoms
The mother may not have symptoms. The mother may notice a gush of fluid from the vagina. The fluid may also leak out slowly. This will lead to constant wetness.
The mother’s belly may be smaller than is expected.
Diagnosis
The doctor will ask about any symptoms and health history. A physical exam will be done. An ultrasound will help to:
- View the uterus and fetus
- Measure fluid levels
- Look for signs of problems in the fetus
- Look for potential causes
The doctor will use a measurement called the amniotic fluid index. It will help to determine if the fluid level is abnormal.
Treatment
Treatment of the cause may relieve the problem.
The doctor will monitor the mother and baby. Regular tests will make sure the fluid level does not continue to drop. They will also help to ensure the fetus’s health. Further treatment may not be needed.
Treatment options for continued oligohydramnios that is causing problems include:
- Amnioinfusion—amniotic fluid is injected into the space around the baby
- Induced labor—if baby is developed enough for birth
There will be more prenatal visits than normal. It is very important to keep these appointments.
Prevention
Oligohydramnios cannot always be prevented. Prenatal care may help to find problems before they effect the fluid level. Make sure to get proper care before, during, and after pregnancy.
RESOURCES
American Pregnancy Association http://americanpregnancy.org
The American Congress of Obstetricians and Gynecologists http://www.acog.org
CANADIAN RESOURCES
Health Canada http://www.hc-sc.gc.ca
The Society of Obstetricians and Gynaecologists of Canada https://sogc.org
References
Amniotic fluid abnormalities. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T905317/Amniotic-fluid-abnormalities . Updated March 29, 2017. Accessed April 7, 2017.
Low amniotic fluid levels: Oligohydramnios. American Pregnancy Association website. Available at: http://americanpregnancy.org/pregnancy-complications/oligohydramnios. Updated August 2015. Accessed April 7, 2017.
Oligohydramnios. March of Dimes website. Available at: http://www.marchofdimes.org/complications/oligohydramnios.aspx. Updated June 2012. Accessed April 7, 2017.
Prenatal ultrasound screening. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T115088/Prenatal-ultrasound-screening . Updated February 5, 2016. Accessed April 7, 2017.
The American College of Obstetricians and Gynecologists Committee. ACOG committee opinion no. 560: Medically indicated late-preterm and early-term deliveries.. Obstet Gynecol. 2013;121(4):908-910. Reaffirmed 2015.