Polyhydramnios is too much fluid in the amniotic sac. The amniotic sac is the “water bag” inside the womb that protects your baby. Usually, there is about 1 liter of fluid by 36 weeks of pregnancy. Polyhydramnios is defined as a measurement, called the amniotic fluid index (AFI), of greater than 25 cm. About 2% of pregnant women have more than 25 cm and have polyhydramnios. Increased amniotic fluid can indicate a problem in the mother or the baby. It can also cause the following:
- Early labor and delivery (preterm delivery)
- Cesarean delivery
- Increased bleeding after delivery
- Reduced growth in the baby
- Cord prolapse
—The umbilical cord descends into the vagina before the baby.
About two-thirds of the time, the cause of polyhydramnios is unknown. One-third of the time, a cause is found. Some causes are related to the mother, and others are related to the baby.
Conditions that can cause polyhydramnios:
- Birth defects in the fetus (anencephaly)
- Rh disease
(a treatable condition that occurs when mother and baby have different blood types)
- Diabetes
in the mother
- Identical twins (twin-to-twin transfusion)
Risk Factors
The presence of a known cause of polyhydramnios (eg, diabetes in the mother) increases the risk of developing it.
Symptoms
Symptoms in the mother:
- Discomfort in the abdomen
- Trouble breathing due to crowding of the lungs (The large uterus in the abdomen pushes up your diaphragm.)
If you have mild polyhydramnios, you may not have any symptoms.
Diagnosis
Your doctor will ask about your symptoms and medical history. She will also do a physical exam. You will probably be referred to a doctor who specializes in obstetrics.
Tests may include the following:
- Ultrasound
—a test that uses sound waves to examine your uterus (womb) and baby
- Amniotic fluid index—shows the amount of amniotic fluid based on the ultrasound picture. More than 25 cm means you have polyhydramnios.
- Blood glucose—a blood test to check for diabetes
- Amniocentesis
—a test in which some amniotic fluid is removed for chromosome analysis to check for possible birth defects
Treatment
You will probably have more frequent prenatal visits and regular ultrasound tests. It is very important to keep these appointments.
About half the time, polyhydramnios gets better without any treatment at all. In other cases, treating the cause of the increased amniotic fluid takes care of the problem. For example, diabetes treatment may make the polyhydramnios go away.
Your doctor will suggest a treatment plan based on your due date and the amount of amniotic fluid. If treatment is needed, options include the following:
- Removal of amniotic fluid—Your doctor may do a procedure to remove some amniotic fluid. This is similar to amniocentesis, but more fluid is removed.
- Medicine—A medicine may be used to decrease amniotic fluid. It is effective about 90% of the time, but cannot be used in the last eight weeks of pregnancy.
Prevention
The only way to prevent polyhydramnios is to treat the cause. Getting regular check-ups while you are pregnant can help find the problem early.
American Congress of Obstetricians and Gynecologists. Ultrasound in pregnancy.
Practice Bulletin.
2009;101.
Amniotic fluid abnormalities. March of Dimes website. Available at:
http://www.marchofdimes.com/printableArticles/188_1044.asp. Accessed August 3, 2005.
Amniotic fluid abnormalities. March of Dimes website. Available at:
http://www.marchofdimes.com/professional/681_4536.asp. Accessed August 4, 2005.
Cunningham G, et al.
Williams Obstetrics. New York City, NY: Appleton & Lange; 1997.
High amniotic fluid levels: polyhydramnios. American Pregnancy Association website. Available at:
http://www.americanpregnancy.org/labornbirth/highamnioticfluidpolyhydramnios.htm. Accessed August 3, 2005.
Last reviewedDecember 2011by
Ganson Purcell Jr., MD, FACOG, FACPE
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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