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Presented by: Abhinay BhugooML-510
September 2010
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` First trimester screening is a combination of fetal ultrasound and maternal bloodtesting performed during the first trimester of pregnancy. This screening processcan help to determine the risk of the fetus having certain birth defects.Screening tests may be used alone or in combination with other tests.(11th -14th week)
` ultrasound test for fetal nuchal translucency (NT)Nuchal translucency screening uses an ultrasound test to examine the area at
the back of the fetal neck for increased fluid.` Nasal bone visibility
not visible in downs syndrome
` two maternal serum (blood) testsThe blood tests measure two substances found in the blood of all pregnantwomen: pregnancy-associated plasma protein screening (PAPP-A) - a protein produced by the
placenta in early pregnancy. Abnormal levels are associated with an increased risk forchromosome abnormality.
Beta-human chorionic gonadotropin (-hCG) - a hormone produced by the placenta inearly pregnancy. Abnormal levels are associated with an increased risk for chromosomeabnormality.
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` Used for diagnosis of birth defects such as Down
syndrome, trisomy 18, or trisomy 13.
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` Usually between the 15th and 20th weeks of
pregnancy
` alpha-fetoprotein screening (AFP) - a blood test that
measures the level of alpha-fetoprotein in the mothers'
blood during pregnancy. AFP is a protein normally
produced by the fetal liver and is present in the fluid
surrounding the fetus (amniotic fluid), and crosses the
placenta into the mother's blood. The AFP blood test is
also called MSAFP (maternal serum AFP).
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`Abnormal levels of AFP may signal the
following: open neural tube defects (ONTD) such as spina bifida
Down syndrome other chromosomal abnormalities
defects in the abdominal wall of the fetus
twins - more than one fetus is making the protein
a miscalculated due date, as the levels vary throughout
pregnancy
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Diagram of alpha-fetoprotein (AFP) concentration across gestational age infetal plasma, amnionic fluid, and maternal
serum. The scale refers to the fetal plasma level, which is approximately150 times greater than the amnionic fluid
concentration and 50,000 times greater than the maternal serumconcentration.
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` hCG - human chorionic gonadotropin hormone (a
hormone produced by the placenta)
` estriol - a hormone produced by the placenta
` inhibin - a hormone produced by the placenta
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` Abnormal test results of AFP and other markers may
indicate the need for additional testing.
` ultrasound is performed to confirm the dates of the
pregnancy and to look at the fetal spine and other body
parts for defects.
` amniocentesis
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` An amniocentesis is a procedure used to obtain a small
sample of the amniotic fluid that surrounds the fetus to
diagnose chromosomal disorders and open neural tube
defects (ONTDs) such as spina bifida
` between the 15th and 20th weeks of pregnancy who areat increased risk for chromosome abnormalities, such as
women who are over age 35 years of age at delivery, or
those who have had an abnormal maternal serum
screening test` small risk of miscarriage associated with amniocentesis
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` Chorionic villus sampling (CVS) is a prenataltest that involves taking a sample of some of theplacental tissue
` This tissue contains the same genetic materialas the fetus and can be tested for chromosomalabnormalities and some other genetic problems.
` Ultrasound is used to guide the catheter (fortransvaginal CVS) or needle (for transabdominal
CVS) into place near the placenta.
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` Using a fetoscope (a type of stethoscope) to listen to
the fetal heart beat is the most basic type of fetal heart
rate monitoring.
` Another type of monitoring is with a hand held Doppler
device
` During contractions, an external tocodynamometer (a
monitoring device that is placed over the top of the
uterus with a belt) can record the patterns of
contractions.` Cardiotocography(CTG)
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` glucose tolerance test
A glucose tolerance test, usually conducted in the
24 to 28 weeks of pregnancy, measures levels of
sugar (glucose) in the mother's blood. Abnormalglucose levels may indicate gestational diabetes.
` Rhesus factor
Hemolytic disease of newborn
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` found in the lower genital tract of about 25 percent
of all women.
` GBS may cause chorioamnionitis (a severe
infection of the placental tissues) and postpartuminfection
` GBS is the most common cause of life-threatening
infections in newborns, including pneumonia and
meningitis.
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` cystic fibrosis
` Duchenne muscular dystrophy
` hemophilia A
` thalassemia` sickle cell anemia
` polycystic kidney disease
` Tay-Sachs disease
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Genetic screening methods may include the following:
` ultrasound scan
` alpha-fetoprotein test (AFP) or multiple marker test
` chorionic villus sampling (CVS)` amniocentesis
` percutaneous umbilical blood sampling (withdrawing asmall sample of the fetal blood from the umbilical cord)
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weeks
First visit 15-20 24-28 29-41
history
complete
updated
Physical examination
complete
Blood pressure
maternal weight
Pelvic cervical
examination
Fundal height
Fetal heart
rate/position
A Performed at 28 weeks, if indicated.BTest should be offered.C High-risk women should be retested at the beginning of the third
trimester.DHigh-risk women should be screened at the first prenatal visitand again in the third trimester.E Rectovaginal culture should be obtained between 35 and 37weeks.
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weeks
First visit 15-20 24-28 29-41
Laboratory test
Hemotocrite of
hemoglobin
Blood type and Rh factor
Antibody screening A
Pap smear screening
Glucose tolerance test
Fetal aneuploidy
screening
Ba and/or B
Neural-tube defect
screening
B
Cystic fibrosis screening B or B
Urine protein assesment
Urine culture
Rubella serology
Syphilis serology C
Gonococcal culture D D
Chlamydia culture C
Hepatitis B serology
HIV serology B
Group B streptococcus
culture
E
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` 1. Diagnosis and confirmation of early pregnancy
The gestational sac can be visualized as early as
four and a half weeks of gestation and the yolk
sac at about five weeks. The embryo can beobserved and measured by about five and a half
weeks. Ultrasound can also very importantly
confirm the site of the pregnancy is within the
cavity of the uterus.
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` 2. Vaginal bleeding in early pregnancy.
The viability of the fetus can be documented in
the presence ofvaginal bleeding in early
pregnancy.` visible heartbeat
` Missed abortions and blighted ovum will usually
give typical pictures of a deformed gestational sac
and absence of fetal poles or heart beat.
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` 3. Determination of gestational age and
assessment of fetal size (foetometry)
a) The Crown-rump length (CRL)
b) The Biparietal diameter(BPD)c) The Femur length (FL)
d) The Abdominal circumference (AC)
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` 4. Diagnosis of fetal malformation (can usually
be made before 20 weeks).
` Common examples include hydrocephalus,
anencephaly, myelomeningocoele,achondroplasia and other dwarfism, spina bifida,
exomphalos, Gastroschisis, duodenal atresia
and fetal hydrops.
` . With more recent equipment, conditions suchas cleft lips/ palate and congenital cardiac
abnormalities are more readily diagnosed and at
an earlier gestational age.
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` 5. Placental localization.` 6. Multiple pregnancies.` 7. Hydramnios and Oligohydramnios` 8. Other areas.Ultrasonography is of great value in other obstetric conditions
such as:a) confirmation of intrauterine death.
b) confirmation of fetal presentation in uncertain cases.c) evaluating fetal movements, tone and breathing in thebiophysical profile.d) diagnosis of uterine and pelvic abnormalities during pregnancy
e.g. fibromyomata and ovarian cyst.
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` Transvaginal Scans
` Doppler Ultrasound
` 3-D and 4-D Ultrasound
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