Amniotic fluid is the fluid that surrounds the fetus in the uterus. The fluid and fetus are contained in membranes called the amniotic sac. Problems with amniotic fluid include
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Too much amniotic fluid
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Too little amniotic fluid
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Infection of the fluid, amniotic sac, and/or placenta (called an intra-amniotic infection)
Pregnancy complications, such as too much or too little amniotic fluid, are problems that occur only during pregnancy. They may affect the woman, the fetus, or both and may occur at different times during the pregnancy. However, most pregnancy complications can be effectively treated.
Too much amniotic fluid
Too much amniotic fluid (polyhydramnios or hydramnios) stretches the uterus and puts pressure on the diaphragm of pregnant women.
Too much fluid may accumulate because of the following:
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Diabetes in the pregnant woman
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More than one fetus (multiple births)
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Anemia in the fetus, such as that caused by Rh antibodies to the fetus’s blood produced by the pregnant woman (Rh incompatibility)
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Birth defects in the fetus, especially a blockage in the esophagus or urinary tract
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Other disorders in the fetus, such as infections or a genetic disorder
However, about half the time, the cause is unknown.
Too much amniotic fluid can lead to several problems:
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The woman may have severe breathing problems.
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The uterus become stretched out and not be able to contract normally (a condition called uterine atony).
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The woman may have bleeding from the vagina after delivery.
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Labor may begin early—before 37 weeks of pregnancy (preterm labor).
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The membranes around the fetus may rupture too soon (called premature rupture of the membranes).
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The fetus may be in an abnormal position or presentation, sometimes requiring cesarean delivery.
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The umbilical cord may come out of the vagina before the baby (called a prolapsed umbilical cord).
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The fetus may die.
The placenta may detach from the wall of the uterus too soon (called placental abruption) if premature rupture of the membranes occurs.
Having too much amniotic fluid may cause no symptoms.
Too little amniotic fluid
There tends to be too little amniotic fluid in the following situations:
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The fetus has birth defects in the urinary tract, particularly in the kidneys.
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The fetus has not grown as much as expected (called intrauterine growth restriction).
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The fetus has died.
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The fetus has a chromosomal abnormality.
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The placenta is not functioning normally (as a result, the fetus may not grow as much as expected).
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The membranes around the fetus rupture too soon (called premature rupture of the membranes) or near the due date.
In many cases, the cause is unknown.
Taking certain drugs such as angiotensin-converting enzyme (ACE) inhibitors (including enalapril or captopril) during the 2nd and 3rd trimesters can result in too little amniotic fluid. These drugs are usually avoided during pregnancy. However, rarely, they are used to treat severe heart failure. Taking nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen) during pregnancy can also reduce the amount of amniotic fluid.
Too little amniotic fluid (oligohydramnios) can also cause problems, such as the following:
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If the amount of fluid is greatly reduced, the fetus may be compressed, resulting in deformities in the limbs, a flattened nose, a recessed chin, and other problems.
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The fetus's lungs may not mature normally. (The combination of immature lungs and deformities is called Potter syndrome.)
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The fetus may not be able to tolerate labor, making cesarean delivery necessary.
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The fetus may die.
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The fetus may not grow as much as expected.
Women may notice that the fetus is not moving as much as earlier in the pregnancy.
Symptoms
Usually, having too much or too little amniotic fluid does not cause symptoms in the woman. The woman may sense that the fetus is not moving as much as expected. Sometimes, when the amount of excess amniotic fluid is large, women have difficulty breathing or painful contractions before their due date.
Disorders causing or contributing to too much or too little amniotic fluid may cause symptoms.
Diagnosis
Doctors may suspect too much or too little amniotic fluid when the uterus is too large or too small for the length of the pregnancy.
Sometimes the problem is incidentally detected during ultrasonography. If a problem is detected, doctors can use ultrasonography to determine how much amniotic fluid is present.
If doctors detect too much or too little amniotic fluid, they check for a possible cause. For example, they may examine the vagina and cervix to determine whether the membranes around the fetus have ruptured too soon.
Blood tests may be done to check for disorders that can affect amniotic fluid (such as infections or diabetes). Ultrasonography and other tests (possibly amniocentesis) may be done to check for birth defects and genetic abnormalities in the fetus.
Treatment
Ultrasonography is done regularly to monitor how much the fetus is growing and to measure the amniotic fluid levels. The fetus’s heart rate is also regularly monitored when the fetus is lying still and as it moves. This test is done to check on the fetus's well-being (called nonstress testing).
Any underlying disorders, such as diabetes and high blood pressure, are treated.
When there is too much amniotic fluid, doctors rarely remove the excess fluid. However, the amniotic fluid can be removed with a needle through the woman's abdomen when
When there is too much amniotic fluid, doctors plan to deliver the baby at 39 weeks in certain cases.
When there is too little amniotic fluid, most experts may recommend delivery between 36 and 37 weeks depending on how the fetus is doing.
Drugs Mentioned In This Article
| Generic Name | Select Brand Names |
|---|---|
ibuprofen |
ADVIL, MOTRIN IB |
enalapril |
VASOTEC |
captopril |
CAPOTEN |
