pregnancy & prenatal diagnosis , inborn defects.....

1. Pregnancy diagnosis :
by
s Palaniananth
B.sc Biotechnology III RD

2. Pregnancy:
 It can define as the condition of having a
developing a embryo or fetus in the body after
successful conception
Duration of pregnancy :
 Calculated in term of 10 lunar months /9
calender months and 7days 280 days 40 weeks.
 Calculated from 1st day of last menstrual
period
 Also called menstrual or gestational age

3.  First trimester : first 12 weeks
 Second trimester : 13 -28 weeks
 Last trimester : 29 -40 weeks

5. LIFE IN WOMB 9 MONTHS

6. PRESUMPTIVE SIGN :
 AMENORRHEA : ABSENCES OF MENSTRUATION MORE
THAN 3 MONTHS .
 MORNING SICKNESS : NAUSEA AND VOMITING .THESE
SYMPTOMES DISAPPER SPANTANEOUSLY FROM 6 TO 12
WEEKS (FIRST TRIMESTER)
 ENLARGEMENT OF BREASTS : INCREASED SIZE &SENSITIVITY
OF BREASTS AND NIPPLS INCREASED VASCULARITY AND
APPERANCE OF SUBCUTANEOUS VENIS.
 DARK PIGMENT OF THE NIPPLS AND AREOLA.
 SECRETION OF CLOSTRUM
 FREQUENCY OF MICTURITION :
 INCREASED DURING 8TH TO 12TH WEEK OF PREGNANCY.
RESTING OF BULKY UTERUS ON FUNDUS OF BLADDER
CONGESTION OF BLADDER MUCOSA
CHANGES IN MATERNAL OSMOREGULATION CAUSES
INCREASED THIST & POLYURIA .
Hyperpigmentation : MELASMA ,LINCANIGRA
Quickening : 12 to14 weeks women feel fetus moment movement

7. Probable evidence :
GOODELL’S SIGN :Tips of cervix become soft and swollen
CHADWICK’S SIGN: cervix and vagina a violet bluish colour
BALLOTTEMENT :its an bimanually evident from 16th week .
Uterine ‘s sign : The uterus become large in size ,globular in
shape and soft in consistence. By the end of third month the funds
of the uterus can be felt just above symphysis pubis.
Hegar ‘s sign: It is the sofening of isthmus of the uterus the area between the
cervix and body of uterus ,which occur at 6to 8 weeks of pregnancy. This area
may become so soft that on bimanual examination the anterior fornix finger and
abdominally fingers meet each other

8. HEGAR SIGN

9. Positive sign:
Fetal heart sounds : These are usually heard by the 24th
week. The presence is sue sign of pregnancy, their rate
of fetal heart sounds is between 120 to 140 under
normal condition.
Visualization of fetus : By ultra sound scanning.
HCG (HUMAN CHRONIC GONADATROPHIN )
Hormone found in blood and urine of pregnant women
*(HCG is an embryonic hormone that maintains secretion of progesterone and estrogen by
the uterus lining through the first trimester. The level of HCG in maternal blood is so high
that it is present in the urine, which allows it to be detected for pregnancy tests.)*

13. Prenatal diagnosis employs a variety of techniques to
determine the health and condition of an unborn fetus.
Without knowledge gained by prenatal diagnosis, there could
be an untoward outcome for the fetus or the mother or both.
Congenital anomalies account for 20 to 25% of perinatal
deaths. Specifically, prenatal diagnosis is helpful for:
 Managing the remaining weeks of the pregnancy
 Determining the outcome of the pregnancy
 Planning for possible complications with the birth
process
 Planning for problems that may occur in the newborn
infant
 Deciding whether to continue the pregnancy
 Finding conditions that may affect future pregnancies

14. There are a variety of non-invasive and invasive techniques
available for prenatal diagnosis. Each of them can be applied
only during specific time periods during the pregnancy for
greatest utility. The techniques employed for prenatal
diagnosis include:
 Ultrasonography
 Amniocentesis
 Chorionic villus sampling
 Fetal blood cells in maternal blood
 Maternal serum alpha-fetoprotein
 Maternal serum beta-HCG
 Maternal serum estriol
 Karyotyping
 Radiography

15.  Ultrasonography :
This is a non-invasive procedure that is harmless
to both the fetus and the mother. High frequency
sound waves are utilized to produce visible
images from the pattern of the echos made by
different tissues and organs, including the baby in
the amniotic cavity. The developing embryo can
first be visualized at about 6 weeks gestation.
Recognition of the major internal organs and
extremities to determine if any are abnormal can
best be accomplished between 16 to 20 weeks
gestation

16. o Although an ultrasound examination can be quite
useful to determine the size and position of the
fetus, the size and position of the placenta, the
amount of amniotic fluid, and the appearance of
fetal anatomy, there are limitations to this
procedure. Subtle abnormalities may not be
detected until later in pregnancy, or may not be
detected at all.
o A good example of this is Down syndrome
(trisomy 21) where the morphologic abnormalities
are often not marked, but only subtle, such as
nuchal thickening.

17. Ultrasonography

20. AMNIOCENTESIS :
This is an invasive procedure in which a needle is passed
through the mother's lower abdomen into the amniotic cavity
inside the uterus.
 Enough amniotic fluid is present for this to be
accomplished starting about 14 weeks gestation.
 For prenatal diagnosis, most amniocenteses are
performed between 14 and 20 weeks gestation. However,
an ultrasound examination always proceeds
amniocentesis in order to determine gestational age, the
position of the fetus and placenta, and determine if enough
amniotic fluid is present.
o Within the amniotic fluid are fetal cells (mostly derived
from fetal skin) which can be grown in culture for
chromosome analysis, biochemical analysis, and
molecular biologic analysis.

21. In the third trimester of pregnancy, the amniotic
fluid can be analyzed for determination of fetal lung
maturity.
 This is important when the fetus is below 35 to 36
weeks gestation, because the lungs may not be
mature enough to sustain life.
 This is because the lungs are not producing
enough surfactant. After birth, the infant will
develop respiratory distress syndrome from
hyaline membrane disease.
 The amniotic fluid can be analyzed by
fluorescence polarization (fpol), for
lecithin:sphingomyelin (LS) ration, or for
phosphatidyl glycerol (PG).

22. Risks with amniocentesis are uncommon, but include fetal
loss and maternal Rh sensitization.
 The increased risk for fetal mortality following
amniocentesis is about 0.5% above what would normally
be expected.
 Rh negative mothers can be treated with RhoGam.
Contamination of fluid from amniocentesis by maternal
cells is highly unlikely.
 If oligohydramnios is present, then amniotic fluid cannot
be obtained.
 It is sometimes possible to instill saline into the amniotic
cavity and then remove fluid for analysis

24. CHORIONIC VILLUS SAMPLING (CVS)
In this procedure, a catheter is passed via the vagina through
the cervix and into the uterus to the developing placenta
under ultrasound guidance.
 Alternative approaches are transvaginal and
transabdominal.
 The introduction of the catheter allows sampling of cells
from the placental chorionic villi.
 These cells can then be analyzed by a variety of
techniques.
 The most common test employed on cells obtained by CVS
is chromosome analysis to determine the karyotype of the
fetus.
 The cells can also be grown in culture for biochemical or
molecular biologic analysis. CVS can be safely performed
between 9.5 and 12.5 weeks gestation.

25. CVS has the disadvantage of being an invasive
procedure, and it has a small but significant rate of
morbidity for the fetus; this loss rate is about 0.5 to
1% higher than for women undergoing
amniocentesis.
 Rarely, CVS can be associated with limb defects
in the fetus. The possibility of maternal Rh
sensitization is present.
 There is also the possibility that maternal blood
cells in the developing placenta will be sampled
instead of fetal cells and confound chromosome
analysis

28. KARYOTYPING
 Tissues must be obtained as fresh as possible
for culture and without contamination.
 A useful procedure is to wash the tissue samples
in sterile saline prior to placing them into cell
culture media.
 Tissues with the best chance for growth are
those with the least maceration: placenta, lung,
diaphragm.
 Obtaining tissue from more than one site can
increase the yield by avoiding contamination or
by detection of mosaicism

31. DNA PROBES : (is single standard seqences that is complementary to know the region od dna)
 Fetal cells obtained via amniocentesis or CVS can be analyzed by
probes specific for DNA sequences.
 One method employs restriction fragment length polymorphism
(RFLP) analysis.
 This method is useful for detection of mutations involving genes that
are closely linked to the DNA restriction fragments generated by the
action of an endonuclease. The DNA of family members is analyzed to
determine differences by RFLP analysis.
 In some cases, if the DNA sequence of a gene is known, a probe to a
DNA sequence specific for a genetic marker is available, and the
polymerase chain reaction (PCR) technique can be applied for
diagnosis.
 There are many genetic diseases, but only in a minority have
particular genes been identified, and tests to detect them have been
developed in some of these. Thus, it is not possible to detect all
genetic diseases. Moreover, testing is confounded by the presence of
different mutations in the same gene, making testing more complex.

33. and then detect the matches by using x-ray flim

34. MATERNAL SERUM ESTRIOL
 The amount of estriol in maternal serum is dependent
upon a viable fetus, a properly functioning placenta, and
maternal well-being.
 The substrate for estriol begins as
dehydroepiandrosterone (DHEA) made by the fetal adrenal
glands. This is further metabolized in the placenta to
estriol.
 The estriol crosses to the maternal circulation and is
excreted by the maternal kidney in urine or by the
maternal liver in the bile. The measurement of serial estriol
levels in the third trimester will give an indication of
general wellbeing of the fetus.
 If the estriol level drops, then the fetus is threatened and
delivery may be necessary emergently.
 Estriol tends to be lower when Down syndrome is present
and when there is adrenal hypoplasia with anencephaly.22

35. FISH (PERFORMED ON FRESH TISSUE OR PARAFFIN
BLOCKS)
 In addition to karyotyping, fluorescence in situ
hybridization (FISH) can be useful. A wide variety of probes
are available. It is useful for detecting aneuploid conditions
(trisomies, monosomies).
 Fresh cells are desirable, but the method can be applied
even to fixed tissues stored in paraffin blocks, though
working with paraffin blocks is much more time consuming
and interpretation can be difficult. The ability to use FISH
on paraffin blocks means that archival tissues can be
examined in cases where karyotyping was not performed,
or cells didn't grow in culture.

38. RADIOGRAPHY
 Standard anterior-posterior and lateral radiographic views are essential
for analysis of the fetal skeleton. Radiographs are useful for
comparison with prenatal ultrasound, and help define anomalies when
autopsy consent is limited, or can help to determine sites to be
examined microscopically. Conditions diagnosed by postmortem
radiography may include:
 Skeletal anomalies (dwarfism, dysplasia, sirenomelia, etc.)
 Neural tube defects (anencephaly, iniencephaly, spina bifida, etc.)
 Osteogenesis imperfecta (osteopenia, fractures)
 Soft tissue changes (hydrops, hygroma, etc.)
 Teratomas or other neoplasms
 Growth retardation
 Orientation and audit of fetal parts (with D&E specimens)
 Assessment of catheter or therapeutic device placement

39. dysplasia

40. Radiograph

41. MICROBIOLOGIC CULTURE
 Culture can aid in diagnosis or confirmation of congenital
infections. Examples of congenital infection include:
 T - toxoplasmosis
 O - other, such as Listeria monocytogenes, group B
streptococcus, syphilis
 R - rubella
 C - cytomegalovirus
 H - herpes simplex or human immunodeficiency virus
(HIV)
 Cultures have to be appropriately obtained with the proper
media and sent with the proper requisitions ("routine"
includes aerobic and anaerobic bacteria; fungal and viral
cultures must be separately ordered).
 Viral cultures are difficult and expensive. Separate media
and collection procedures may be necessary depending
upon what virus is being sought.
 Bacterial contamination can be a problem

42. THANK YOU