Amniotic
fluid provides cushioning for your baby. She can move around
in it and strengthen her bones and muscles. If you have too
little amniotic fluid it is called oligohydramnios; if you have
too much amniotic fluid it is called polyhydramnios.
What
is Oligohydramnios?
About
eight percent of pregnant women will have low amniotic fluid
and four percent will be diagnosed with oligohydramnios. Oligohydramnios
(low amniotic fluid) is diagnosed from ultrasound findings.
Your doctor will measure the pockets of amniotic fluid surrounding
your baby to determine how much amniotic fluid you have.
Amniotic
Fluid Index (AFI)
There
are several ways that doctors determine how much amniotic
fluid a woman has but the most common measurement is the amniotic
fluid index or AFI. Your doctor will measure the largest pockets
of amniotic fluid in four different quadrants of your uterus.
He will add up these measurements and the total will be your
AFI. If your amniotic fluid index is less than 5 centimeters
then you have oligohydramnios (low amniotic fluid); if it
is greater than 25 centimeters, you have polyhydramnios.
What
causes oligohydramnios (low amniotic fluid)?
In the
majority of cases the cause of oligohydramnios is unknown.
Some other causes of low amniotic fluid include:
- premature
rupture of membranes or leaking membranes
- problems
with the placenta
- intrauterine
growth restriction
- birth
defects (particularly kidney or urinary tract defects)
- certain
maternal medical conditions (such as diabetes, preeclampsia,
lupus, or high blood pressure)
- twin-to-twin
transfusion syndrome
- post
term pregnancy
How is
oligohydramnios (low amniotic fluid) treated?
If you
are diagnosed with oligohydramnios your doctor will want to
monitor you very closely. You will likely receive weekly or
more frequent ultrasounds to make sure that your amniotic
fluid is not decreasing. You may be given non-stress tests
or be asked to do
fetal kick counts to see how your baby is doing. If your
amniotic fluid decreases your doctor may want to induce labor.
Low amniotic fluid may increase your risks of complications
during labor. The concern with oligohydramnios is that the
fluid may become so low that there is nothing cushioning the
umbilical cord and it becomes compressed. If this happens,
it can cause your baby to go into distress. To help avoid
labor complications your doctor may insert a tube into your
cervix during your labor that will fill your uterus with saline
fluid. If your baby shows signs of distress a c-section may
become necessary.
