Amniotic Fluid Problems / Hydramnios / Oligohydramnios
Amniotic Fluid Problems / Hydramnios /
Oligohydramnios
What is amniotic fluid?
Amniotic
fluid is an important part of pregnancy and fetal development. This watery
fluid is inside a casing called the amniotic membrane (or sac) and fluid
surrounds the fetus throughout pregnancy. Normal amounts may vary, but,
generally, women carry about 500 ml of amniotic fluid. Amniotic fluid helps
protect and cushion the fetus and plays an important role in the development of
many of the fetal organs including the lungs, kidneys, and gastrointestinal
tract. Fluid is produced by the fetal lungs and kidneys. It is taken up with
fetal swallowing and sent across the placenta to the mother's circulation.
Amniotic fluid problems occur in about 7 percent of pregnancies. Too much or
too little amniotic fluid is associated with abnormalities in development and
pregnancy complications. Differences in the amount of fluid may be the cause or
the result of the problem.
What is hydramnios?
Hydramnios
is a condition in which there is too much amniotic fluid around the fetus. It
occurs in about 3 to 4 percent of all pregnancies. It is also called
polyhydramnios.
What causes hydramnios?
There are
several causes of hydramnios. Generally, either too much fluid is being
produced or there is a problem with the fluid being taken up, or both. Factors
that are associated with hydramnios include the following:
- Maternal factors:
- diabetes
- Fetal factors:
- gastrointestinal
abnormalities that block the passage of fluid
- abnormal
swallowing due to problems with the central nervous system or chromosomal
abnormalities
- twin-to-twin
transfusion syndrome
- heart failure
- congenital
infection (acquired in pregnancy)
Why is hydramnios a concern?
Too much
amniotic fluid can cause the mother's uterus to become overdistended and may
lead to preterm labor or premature rupture of membranes (the amniotic sac).
Hydramnios is also associated with birth defects in the fetus. When the
amniotic sac ruptures, large amounts of fluid leaving the uterus may increase
the risk of placental abruption (early detachment of the placenta) or umbilical
cord prolapse (when the cord falls down through the cervical opening) where it
may be compressed.
What are the symptoms of hydramnios?
The
following are the most common symptoms of hydramnios. However, each woman may
experience symptoms differently. Symptoms may include:
·
rapid growth of
uterus
·
discomfort in the
abdomen
·
uterine contractions
The
symptoms of hydramnios may resemble other medical conditions. Always consult
your physician for a diagnosis.
How is hydramnios diagnosed?
In
addition to a complete medical history and a physical examination, hydramnios
is usually diagnosed with ultrasound (a test using sound waves to create a
picture of internal structures) by measuring pockets of fluid to estimate the
total volume. In some cases, ultrasound is also helpful in finding a cause of
hydramnios, such as multiple pregnancy or a birth defect.
Treatment for hydramnios:
Specific
treatment for hydramnios will be determined by your physician based on:
- your pregnancy, overall health, and
medical history
- extent of the condition
- your tolerance for specific
medications, procedures, or therapies
- expectations for the course of the
condition
- your opinion or preference
Treatment
for hydramnios may include:
- close
monitoring the amount of amniotic fluid and frequent follow-up visits with
the physician
- medication (to
decrease fetal urine production)
- amnioreduction
- amniocentesis (inserting a needle through the uterus and into the
amniotic sac) to remove some of the amniotic fluid; this procedure may
need to be repeated.
- delivery (if
complications endanger the well-being of the fetus or mother, then an
early delivery may be necessary)
The goal
of treatment is to relieve the mother's discomfort and continue the pregnancy.
What is oligohydramnios?
Oligohydramnios
is a condition in which there is too little amniotic fluid around the fetus. It
occurs in about 4 percent of all pregnancies.
What causes oligohydramnios?
There are
several causes of oligohydramnios. Generally, it is caused by conditions that
prevent or reduce amniotic fluid production. Factors that are associated with
oligohydramnios include the following:
- premature rupture of membranes (before
labor)
- intrauterine growth restriction (poor
fetal growth)
- post-term pregnancy
- birth defects, especially kidney and
urinary tract malformations
- twin-to-twin transfusion syndrome
Why is oligohydramnios a concern?
Amniotic
fluid is important in the development of fetal organs, especially the lungs. Too
little fluid for long periods may cause abnormal or incomplete development of
the lungs called pulmonary hypoplasia. Intrauterine growth restriction (poor
fetal growth) is also associated with decreased amounts of amniotic fluid.
Oligohydramnios may be a complication at delivery, increasing the risk for
compression of the umbilical cord and aspiration of thick meconium (baby's
first bowel movement).
What are the symptoms of
oligohydramnios?
The
following are the most common symptoms of oligohydramnios. However, each woman
may experience symptoms differently. Symptoms may include:
- leaking of amniotic fluid when the
cause is rupture of the amniotic sac
- decreased amount of amniotic fluid on
ultrasound
The
symptoms of the oligohydramnios may resemble other medical conditions. Always
consult your physician for a diagnosis.
How is oligohydramnios diagnosed?
In
addition to a complete medical history and physical examination, a diagnosis is
usually made using ultrasound. Pockets of amniotic fluid can be measured and
the total amount estimated. Ultrasound can also show fetal growth, the
structure of the kidneys and urinary tract, and detect urine in the fetal
bladder. Doppler flow studies (a type of ultrasound used to measure blood flow)
may be used to check the arteries in the kidneys.
Treatment for oligohydramnios:
Specific
treatment for oligohydramnios will be determined by your physician based on:
- your pregnancy, overall health, and
medical history
- extent of the condition
- your tolerance for specific medications,
procedures, or therapies
- expectations for the course of the
condition
- your opinion or preference
Treatment
for oligohydramnios may include:
- closely
monitoring the amount of amniotic fluid and frequent follow-up visits with
the physician
- amnioinfusion -
instilling a special fluid into the amniotic sac to replace lost or low
levels of amniotic fluid. Amnioinfusion is still experimental, but it may
be offered during pregnancy in an attempt to help prevent pulmonary
hypoplasia (underdeveloped lungs), or at delivery to help prevent
compression of the umbilical cord.
- delivery (if
oligohydramnios endangers the well-being of the fetus, then an early
delivery may be necessary)
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