diagnosis and tests of embryo and fetus : prenatal diagnosis

1. JIMMA UNIVERSITY
SCHOOL OF BIOMEDICAL SCIENCES
DEPARTMENT OF ANATOMY
EMBRYOLOGY ASSIGNMENT
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2. Diagnosis And Test Of
Embryo And Fetus
By: Eyassu Kassahun(BSc. MSc student)
Submitted to: Mr. Getachew C.(BSc. MSc. And PHD fellow)
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3. Outline
• Objective
• Introduction
• Indication
• Importance
• Types
• Non Invasive methods
• Invasive Methods
• Ethical debate
• Summary
• reference
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4. Objective
• Understand the definition of prenatal diagnosis.
• Identify the indications and importance of prenatal diagnosis.
• Differentiate between the types of prenatal diagnosis.
• Explain the different types of invasive prenatal diagnosis and
non invasive prenatal diagnosis.
• Identify the ethical debate of preimplantation diagnosis
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5. Introduction
• Prenatal tests/Diagnosis are medical tests pregnant women
get during pregnancy.
• Procedures undertaken to diagnose genetic abnormalities and
structural anomalies often on early embryo and fetus in order to
undertake timely prenatal counseling and appropriate
interventions.
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6. Con’t
• Embryo testing and treatments can be used by people who have
serious inherited diseases in their family and want to avoid
passing the disease onto their children.
• There several approaches for assessing growth and development
of the fetus in utero, including ultrasound, amniocentesis,
chorionic villus sampling, and maternal serum screening.
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7. Con’t
• In combination, these techniques are designed to detect
malformations, genetic abnormalities, overall fetal growth, and
complications of pregnancy, such as placental or uterine
abnormalities.
• Their use and development of in utero therapies have heralded a
new concept in which the fetus is now a patient.
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8. Indications for prenatal diagnosis
• Advanced maternal age
• Previous child with a chromosome abnormality
• Women who are pregnant with multiples (twins or more)
• Family history of single gene disorder
• Family history of a neural tube defect
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9. Con’t
• Family history of other congenital structural abnormalities
• Abnormalities identified in pregnancy
• Women who have previously had miscarriages
• Other high risk factors(consanguinity, Maternal illnesses)
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10. Importance of Prenatal diagnosis
Allows
• To identify structural, functional or chromosomal
abnormalities.
• timely medical treatment of a condition before or after birth
• Parents to make decisions regarding whether to abort a fetus
with diagnosed condition
• Parents to prepare psychologically, socially, financially and
medically for a baby with a health problem or disability
• Determine the outcome of pregnancy
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11. Types: Methods of prenatal diagnosis
Invasive
• Amniocentesis
• Cordocentesis
• CVS
• Coelocentesis
Non-invasive
• Ultrasonography
• MRI
• Cell-free fetal DNA
• Triple test
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12. Invasive Vs Non-Invasive
• In non-invasive prenatal diagnosis there is no need to take a sample
from inside the uterus (in contrast with invasive prenatal diagnosis
using amniotic fluid or chorionic villus sampling).
• This removes the small chance of miscarriage associated with
invasive procedures.
• It can be performed from as early as eight to nine weeks’ gestation
(dependent on the condition to be tested for).
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13. ULTRASONOGRAPHY
• is a safe, commonly used, relatively accurate and non-invasive technique
that uses high-frequency sound waves reflected from tissues to create
images.
• It may be transabdominal or transvaginal, with the latter producing images
with higher resolution.
• It has advanced to a degree where detection of blood flow in major vessels,
movement of heart valves, and flow of fluid in the trachea and bronchi is
possible.
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15. Important parameters revealed by ultrasound include:
• characteristics of fetal age and growth;
• presence or absence of congenital anomalies like anencephaly and
spina bifida, omphalocele and gastroschisis , cleft lip and palate;
• status of the uterine environment, including the amount of amniotic
fluid;
• placental position and umbilical blood flow; and
• whether multiple gestations are present
• Monitor needle or catheter insertion during amniocentesis and
chorionic villus biopsy
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16. Ultrasound may be used at:
• First trimester - to check
• the embryo is developing inside the womb (rather than inside a fallopian
tube)
• confirm the number of embryos,
• calculate the gestational age and the baby’s due date.
• Second trimester - to check
• the development of fetal structures such as the spine, limbs, brain and
internal organs.
• The size and location of the placenta is also checked.
• The baby’s sex can be established, if the parents wish to know.
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17. Con’t
• Third trimester - to check
• the baby is continuing to grow at a normal rate.
• The location of the placenta is checked to make sure it isn’t blocking the
cervix.
• There are no known risks, complications or side effects for either the
mother or her unborn baby.
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18. Limitations
• Small field of view,
• Limited soft-tissue acoustic contrast,
• Beam attenuation by adipose tissue,
• Poor image quality in oligohydramnios, and
• Limited visualization of the posterior fossa after 33 weeks'
gestation because of calvarial calcification.
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19. MRI: Magnetic Resonance Imaging
• MRI can supplement the information obtained from your high-
resolution fetal ultrasound and can provide additional information
regarding your baby’s diagnosis.
• It is performed in the 2nd or 3rd trimester of pregnancy. This type of
examination is used to evaluate abnormalities in your baby's brain,
spine, and body.
• Important advantages of magnetic resonance imaging are that it does
not use ionizing radiation and that it has high soft-tissue contrast
and resolution
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20. Cell-free fetal DNA Screening
• as noninvasive prenatal testing (NIPT) with high sensitivity and specificity
identifying DNA fragments that are derived primarily from apoptotic trophoblasts
• can be performed at any time later 9 to 10 weeks' gestation. Results are available
in 7 to 10 days.
• he screening performance the pooled sensitivity to detect Down syndrome was 99
%, and for trisomies 18 and 13, 96% and 91%, respectively. 90% with Turner
syndrome (45,X) and 93% with sex chromosome aneuploidies other than 45,X.
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21. Cordocentesis
• Fetal blood samples may be obtained directly from the umbilical vein.
• It is used for the diagnosis of many fetal abnormal conditions,
including aneuploidy, fetal growth restriction, fetal infection, and
fetal anemia.
• is usually performed after 18 weeks of gestation under continuous
direct ultrasound guidance, which is used to locate the umbilical cord
and its vessels.
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22. 22

23. Con’t
• It can obtain a sample of blood from a fetus’s umbilical cord to detect
blood disorders, infections and genetic mutations.
• It also permits treating the fetus directly, including the transfusion of
packed red blood cells for the management of fetal anemia or deliver
medications.
• It’s also called percutaneous umbilical cord blood sampling (PUBS)
or funipuncture.
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24. What does cordocentesis test for?
• Blood disorders such as fetal hemolytic disease, when red blood cells
break down quickly, Anemia, Thrombocytopenia.
• Chromosomal abnormalities (inherited or random genetic
mutations), such as Down syndrome.
• Infection, such as toxoplasmosis or rubella.
• Isoimmunization, when a pregnant person’s blood isn’t compatible
with the fetus’s.
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25. AMNIOCENTESIS
• is the most common invasive prenatal diagnostic procedure, usually
performed between 15 and 18(20) weeks gestation.
• Amniocentesis is a procedure in which amniotic fluid and fetal cells
is removed from the uterus for testing or treatment.
• Approximately 20 to 30 ml of amniotic fluid is sampled by inserting
a 22-gauge needle through the mother’s anterior abdominal and
uterine walls into the amniotic cavity by piercing the chorion and
amnion.
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26. 26

27. Con’t
• Amniocentesis is a test used for prenatal diagnosis of
• inherited diseases,
• genital infections
• alloimmunization
• Rh incompatibility,
• neural tube defects,
• lung maturity.
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28. Con’t
• Although amniocentesis does carry some significant risks, the
medical community commonly accepts it as a safe and useful
procedure.
• The amniocentesis procedure-related loss rate approximates 0.
1 to 0.3 percent when performed by an experienced provider
about 1 per 500 procedures.
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29. COMPLICATIONS
A. Maternal Complications:
1. Infection,
2. Hemorrhage (placental or uterine injury),
3. Premature rupture of membranes and premature labor,
4. Maternal iso-immunization in Rh - negative mother.
B. Fetal complications:
1. Trauma
2. Feto-maternal hemorrhage.
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30. Coelocentesis
• Coelocentesis is an invasive technique that can provide prenatal
diagnosis of disorders, from as early as 7 weeks' gestation.
• Fluid take from coelomic space b/n amniotic membrane and
uterine cavity.
• The risk of fetal loss is 0 or less than that of aminocentesis.
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32. MATERNAL SERUM SCREENING
• Maternal serum screening provides a relatively non-invasive
technique for an initial assessment of fetal well being.
• A search for biochemical markers of fetal status led to development
of maternal serum screening tests.
• AFP is produced normally by the fetal liver, peeks at approximately
14 weeks, and “leaks” into the maternal circulation via the placenta.
• Thus, AFP concentrations increase in maternal serum during the
second trimester and then begin a steady decline after 30 weeks of
gestation.
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33. • In cases of neural tube defects and several other abnormalities, including
omphalocele, gastroschisis and others, AFP levels increase in amniotic
fluid and maternal serum.
• In other instances, AFP concentrations decrease as, for example, in Down
syndrome, trisomy 18, and sex chromosome abnormalities.
• These conditions are also associated with lower serum concentrations of
human chorionic gonadotropin (hCG) and unconjugated estriol
• Alpha-fetoprotein(AFP), human chorionic gonadotropin(HCG) and
unconjugated estriol(UE3) are called Triple Tests.
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34. Alpha-Fetoprotein Assay
• An AFP test is a test that is mainly used to measure the level of
alpha-fetoprotein (AFP) in the blood of a pregnant women.
• Alpha-fetoprotein (AFP) is a glycoprotein that is synthesized in the
fetal liver, umbilical vesicle, and gut.
• AFP is found in high concentration in fetal serum, peaking 14 weeks
after the LNMP. Small amounts of AFP normally enter the amniotic
fluid.
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35. • An AFP test is usually done between 15 and 20 weeks of
pregnancy.
• During pregnancy, if your AFP blood levels are higher or lower
than normal, it may be sign that:
• The baby has a high risk of having a genetic disorder
like neural tube defect and down syndrome.
• Your estimated due date is wrong.
• You're pregnant with more than one baby.
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36. Chorionic Villus Sampling
• It involves inserting a needle transabdominally or transcervical into
the placental mass and aspirating approximately 5 to 30 mg of
trophoblastic tissue.
• Biopsy of chorionic villi is typically performed between 10 and 13
weeks' gestation.
• Advantage: results are available earlier in pregnancy, permitting
more time for decision-making.
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37. 37

38. Indications
• Previously affected child or a family history of a genetic disease,
chromosomal abnormalities, or metabolic disorder
• Maternal age over 35 years by the pregnancy due date
• Risk of a sex-linked genetic disease
• Previous ultrasound with questionable or abnormal findings
• Abnormal cell-free DNA test
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39. • Used to detect
• chromosomal abnormalities,
• inborn errors of metabolism,
• X-linked disorders.
• The rate of fetal loss is approximately 1%, slightly more than the
risk from amniocentesis.
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40. Applications of prenatal diagnosis
• Maternal serum screening:- Fetoprotein, estriol and HCG estimation
• Ultrasonography:- Structural abnormalities
• Amniocentesis:-
• Fetoprotein and acetylcholinesterase
• Chromosomal analysis
• Biochemical analysis
• Chorionic villus sampling:-
• DNA analysis
• Chromosomal analysis
• Biochemical analysis
• Fetal blood sampling:-
• Chromosomal analysis
• DNA analysis
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41. Debate: Preimplantation Genetic Testing
• During the process of IVF, Testing involves removing one or a few
cells from the embryo, and analyzing the DNA.
• After testing, the healthiest embryos can be selected, greatly
improving the couple's chances of having a healthy baby.
• The advantage of testing embryos before they are implanted is that
only the ones that are free of harmful genetic conditions are allowed
to develop.
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42. Con’t
• Two main sets of ethical objections make PGD and proposals for
its extension controversial.
• One set of objections arises from the need to create and then select
embryos on chromosomal or genetic grounds, with the deselected
embryos then usually discarded.
• Other objections concern the fact of selection itself.
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43. Summary: key takeaways
• Prenatal tests/Diagnosis are medical tests pregnant women get
during pregnancy undertaken to diagnose genetic abnormalities and
structural anomalies.
• There are invasive and non invasive types of prenatal diagnosis with
the latter having no or less risk on the mother and fetus
• Ultrasonography is a safe, commonly used, relatively accurate and
non-invasive technique
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44. • Amniocentesis is the most common invasive prenatal diagnostic
procedure, usually performed between 15 and 18(20) weeks
gestation.
• Preimplantation Genetic Testing raises ethical objections.
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45. Any Questions?
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46. Reference
• Langman’s medical embryology, 8th edition , T.W. Sadler.
• The developing human, clinically oriented embryology, 9th edition,
Keith L. Moore, T.V.N Persaud, Mark G. Torchia, 2013
• BRS Embryology, 5th edition Ronald W. Dudek, 2011
• William’s Obstatrics, 25th edition, F. Gary Cunningham Kenneth J.
Leveno Steven L. Bloom Jodi S. Dashe Barbara L. Hofman Brian M.
Casey Catherine Y. Spong, 2018
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47. Thank you
For your attention
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