What
does this medical term mean?
In addition to the
information below, a
full glossary of infertility terms is
maintained by the InterNational
Council on Infertility Information Dissemination
(INCIID).
What is a
"blighted ovum"?
A blighted ovum is
an embryo that stops developing early in the pregnancy,
usually due to an incomplete genetic code. The cells divide
and develop until the code runs out and then everything
stops. The embryo is then either reabsorbed by the body or
miscarried.
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What is a
"missed abortion"?
A missed abortion
occurs when the embryo/fetus has died but the body hasn't
shown any signs of miscarriage yet. This is usually
diagnosed by either an ultrasound or hcg decline. If a
miscarriage does not occur to expel the pregnancy, a D&C
or D&E is usually required.
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What is a
"molar pregnancy"?
A molar pregnancy is
a rare condition where a tumor develops in place of the
embryo. One of the early symptoms is being very large for
dates in early pregnancy. Surgery is required to remove the
growth and monthly check-ups for a year or more are needed
to ensure the mole does not redevelop. Pregnancy is not
recommended for 1 year after a molar pregnancy. Occurrence
of a mole slightly increases future risk of uterine
cancer.
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What is
"CVS" or "chorionic villus sampling"?
Chorionic villus
sampling (or CVS) is a test that takes cells from the
placenta to test for chromosomal or other genetic diseases.
It is considered a higher-lever test than amniocentesis and
also has a slightly higher risk of complications than an
amnio. However, risk declines with a more highly experienced
doctor. The advantage over amnio is that it is done much
earlier (by the end of the first trimester) and gives faster
results (some within 24 hours, as opposed to two weeks). CVS
does not measure AFP (alpha fetal protein)
levels.
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What is
"cordocentesis" or "fetal blood sampling"?
In cordocentesis (or
fetal blood sampling), blood is drawn from the umbilical
cord for karyotyping, detection of fetal virus or other
abnormalities. Used for very high-risk cases or late
detection of problems; can be done at 18-40 weeks. Needle is
inserted into umbilical cord where it connects to placental
wall and 1-4 ml of blood is withdrawn. Risk of miscarriage
is 1-2%, risk of preterm labor is 3-4%, risk of IUGR is
8-9%.
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What is
"HCG"?
HCG is a hormome
secreted by the placenta. Detecting HCG is the easiest test
for confirming pregnancy, and this method is used by most
urine test kits. HCG stands for Human Chorionic
Gonadotropin.
HCG levels may be
used to monitor the progress of a pregnancy. Normally, HCG
levels double about every 3 days. Quantitative serum HCG
tests are used to measure HCG levels. The following table
gives a general guide to expected HCG levels
for a normal single pregnancy:
Pregnancy
from LMP
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HCG
level
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3
weeks
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5 -
50
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4
weeks
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40 -
1,000
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5
weeks
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100 -
5,000
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6
weeks
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600 -
10,000
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7 - 8
weeks
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1,500 -
100,000
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9 - 10
weeks
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16,000 -
200,000
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11 - 14
weeks
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12,000 -
300,000
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Second
trimester
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24,000 -
55,000
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Third
trimester
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6,000 -
48,000
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HCG
info published by the
Center for Human Reproduction in Chicago
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SPALS members have
collected numerous links to sites with information about HCG
levels and monitoring -- these are provided for information
only:
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What is a
"level II" or "level III" ultrasound?
The higher levels
refer generally to greater resolution of the ultrasound
image. Ultrasound machinery ranges in price from $10,000 to
$300,000, so you can imagine the quality of what you see on
the scan can be tremendously different. A higher resolution
machine can give much clearer details of the embryo/fetus
and is often used as a non-invasive means of ascertaining
fetal problems.
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What are
"AC", "BPD", "FL" and "HC" in ultrasound measurements?
Abdominal
Circumference (AC) measures the mother's belly in
cross section. Especially later in pregnancy, it is used as
an indicator of fetal weight and growth. Sometimes, serial
measurements are taken to ensure an accurate
reading.
BPD stands
for Biparietal Diameter and is an ultrasound measurement
taken of the baby's head (from side to side). Along with the
Femur Length (FL) and Abdominal Circumference (AC), it is
used to estimate the fetal weight.
Femur Length
(FL) often is measured along with AC and BLD
measurements. The femur is the longest bone in the body and
measurement of this bone is taken to estimate fetal
growth.
AC, BPD and FL are
combined in a formula to estimate fetal weight. While most
ultrasound machines contain calculators, here is the formula
used to figure the fetal weight: 1.4 X BPD X FL X AC (all in
centimeters) - 200 = Fetal weight. (This is an
estimate and becomes less accurate as baby gets
farther from about 5.5 lbs.)
HC indicates
Head Circumference. Babies of the same weight can have
different head sizes.
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