Definition

Oligohydramnios is too little fluid in the amniotic sac. The amniotic sac is the water bag inside the uterus that cushions and protects your baby. It also allows normal growth and development to occur. Normal amniotic fluid levels vary. The average volume during pregnancy is almost one liter at 36-37 weeks.

Low amniotic fluid can indicate a problem in the mother or the baby. It can also cause problems that vary depending on when in pregnancy oligohydramnios occurs.

Problems in the first half of pregnancy may include:

• Higher risk of miscarriage
• Compression of the baby, leading to birth defects
• Lack of lung development

Problems in the second half of pregnancy may include:

• Reduced growth of baby
• Preterm birth
• Fetal distress in labor, possibly leading to cesarean section

Causes

There are many known causes of oligohydramnios. However, sometimes a specific cause cannot 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
• Complication of certain medications

Risk Factors

Factors that increase your chance of getting oligohydramnios include:

• Pregnancy past the due date
• Health problems in the mother or development problems in the baby

Symptoms

Oligohydramnios usually does not cause women to have any symptoms. If the amniotic sac has a tear, you may notice a gush of fluid from the vagina. The fluid may leak out slowly causing constant wetness. Your doctor may also notice that your abdomen is smaller than expected for your gestational age.

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done.

Your doctor will do an ultrasound to view the uterus and fetus. Measurements of the fluid levels will be taken. The fetus will also be closely looked at for any signs of problems.

Your doctor may do other tests including blood tests to check for health problems in the mother. Other tests may be done to look for problems with the fetus’s health.

Treatment

Your doctor will monitor you and your baby closely to make sure the condition does not get worse and that the fetus remains healthy. You will probably have more frequent prenatal visits and regular ultrasound tests. It is very important to keep these appointments.

Treatment options include:

• Increased fluid intake, especially water.
• Your doctor may add fluid to the amniotic sac after you are in labor. This will help cushion the umbilical cord during contractions.

Prevention

The only way to prevent oligohydramnios is to treat its causes if possible. Make sure to get proper care before, during, and after pregnancy. This may include:

• Talking with your doctor about medications, supplements, or herbal treatments you are using before getting pregnant
• Proper diet, adequate rest and fluid intake, taking vitamin supplements, and getting enough exercise
• Regular check-ups throughout pregnancy
• Screening tests

American Pregnancy Association http://www.americanpregnancy.org

The Society of Obstetricians and Gynaecologists of Canada http://www.sogc.org

Pregnancy complication. March of Dimes website. Available at:
http://www.marchofdimes.com/pregnancy/complications_oligohydramnios.html
Updated June 2011. Accessed June 10, 2013.

Prenatal ultrasound screening. EBSCO DynaMed website. Available at:
http://dynamed.ebscohost.com/about/about-us
Updated January 23, 2013. Accessed June 10, 2013.

The American College of Obstetricians and Gynecologists Committee. Medically indicated late-preterm and early-term deliveries. Obstet Gynecol . 2013;121(4):908-910.