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Abruption
See placental abruption.
Alpha Fetal Protein (AFP)
AFP is a genetic test that is usually performed in the second trimester between 16 to 18 weeks. AFP tests the mother's blood for
alpha fetal protein--a protein that is produced by the fetus and appears in the mother's blood during
pregnancy. When a positive amount of AFP is found in the mother's blood, the risk of having a baby with
Down syndrome is increased. This test is
only a screening, it does not give an absolute diagnosis. If your
AFP test comes back positive, your doctor or a genetic counselor will probably recommend
further tests (such as
amniocentesis) to determine whether the baby has
Down syndrome.
In recent years, the AFP blood test has been expanded to include two pregnancy hormones, estriol and human
chorionic gonadotropin (hCG). This test is usually refered to as a triple screen. Some doctors also
recommend a quadruple screen test which includes the AFP, estriol, and hCG, as well as a chemical
produced by the placenta and overies called inhibin-A. These triple screen and quadruple screen tests do
provide the odds as to whether the fetus has
spina bifida,
trisomy 18 (another chromosomal defect), and other
conditions such as severe kidney or liver disease. However, these tests do not give a definite diagnosis and
if the results are positive further testing may be necessary.
To find out more about genetic tests, what they detect, and how they compare, take a look at the
genetic testing section here at HighRisk.org.
More information about the AFP, triple screen, and quadruple screen tests, can also be found at
Kids Health.org
and UpToDate.com.
Amniocentesis
Amniocentesis is the "gold standard" when it comes to prenatal
genetic testing. Amniocentesis is
performed during the second trimester of pregnancy from weeks 15 through 18. Sometimes amniocentesis is
performed before 14 weeks, but this is not common.
Amniocentesis is used to detect genetic disorders, such as
Down syndrome, chromosonal defects,
spina bifida (nural tube
defects), anencephaly (where the brain is partially or completely missing), skeletal diseases, infections,
Rh incompatability, and lung maturity. Also,
amniocentesis can be used to find out the baby's sex.
A specially trained doctor first uses ultrasound to view the growing fetus, uterus, placenta, and
amniotic sac. Then a long needle is inserted through the mother's abdomen and uterus into the amniotic sac
to collect a small amount of amniotic fluid.
The chance of miscarriage is small (roughly 1 out of 200 women will miscarry). If you are considering
amniocentesis, you should check out the doctor who is going to perform the test and ask some questions--
What is the doctor's miscarriage rate? How many amniocentesis tests does the doctor perform each year? Be
proactive and listen to yourself. If a doctor doesn't feel right, look around and find one who you can trust.
For a full description of amniocentesis and how it is performed, look at
MedicineNet.com and
Kids Health.org.
Amniotic Sac
The amniotic sac is a bag or pouch inside the uterus that is made up of two tough membranes. It contains a growing fetus and the amniotic fluid that surrounds
the fetus. Some people call the amniotic sac the "bag of waters."
To see a few drawings of the uterus, amniotic sac, and amniotic fluid, check out
MedLine Plus.
For an an article about amniotic sac development, take a look at
Radiology,
the journal of the Radiological Society of North America.
Anemia
Anemia occurs when red blood cells and
hemoglobin are low in the
mother's blood. Many times there are no symptoms of this condition, but if the anemia is severe enough
the woman can feel tired and weak, be short of breath, have headaches, and have pale skin, gums, and lips.
Testing for anemia usually occurs early in the
first trimester and then again at
the beginning of the
third trimester, around 28 weeks.
Anemia occurs during pregnancy because of the increased need for iron. Since the mother's blood volume increases
by 50% during pregnancy, this can lead to an iron deficiency. In addition, the fetus stores iron in its
body (especially during the third trimester) and will take it from the mother even if she does not have
enough.
Iron deficient anemia can be treated by taking iron pills to help quickly raise the iron level in the blood.
Iron pills should be taken with a glass of orange juice because the vitamin C helps the body to absorb iron.
Also, foods rich in iron should be eaten, including soy products, red meats, green vegetables, and dried
fruits and beans.
For more info about anemia and pregnancy, check out the
March of Dimes.
Antibodies
If a mother is
Rh negative, one of the standard blood
tests given during the first weeks of pregnancy checks for Rh antibodies in the mother's blood stream. This
is very important because if the Rh negative mother is carrying a baby whose blood is Rh positive, the
antibodies in the mother's blood could attack the baby's blood making the baby dangerously
anemic. For more information, take
a look at the
University of Maryland Medical Center page about Rh sensitivity.
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