CONGENITAL ANAMOLIES

1. Congenital abnormalities, Prenatal
diagnosis & Fetal surveillance
DR ZUBINA ADNAN
Assistant Professor
OBS & GYN CMH MZD

2. • The birth of a baby with a congenital abnormality
is a stressful condition for the parents and the
doctor looking after the case such babies live a
life full of handicaps and complexities and are a
burden on the family as well as the society so
antenatal diagnosis is important because
• If the malformation is incompatible with life it
may be terminated.
• certain abnormalities are correctable in utero &
some in neonatal period

3. Classification of congenital
malformations
• Chromosomal abnormalities: a. trisomy 21 b. trisomy 18
c. trisomy 13
• Structural abnormalities:
a. GIT system: esophageal or duodenal atresia, gastroschisi,
omphalocele, imperforate anus.
b. CNS: microcephaly, hydrocephaly, spina bifida,
anencephaly
c. Renal system: renal agenesis, polycystic kidney,
d. CVS: AV septal defect,
e. Musculoskeletal: achondroplasia
f. Genetic disorders: inborn errors of metabolism,
hemoglobinopathies

4. PRENATAL DIAGNOSIS
• Screening procedures: by screening procedure we mean a
procedure which is simple cheap least invasive completely safe and
easily repeatable having high specificity sensitivity and predictive
values and the test should be available to all. Following are the
methods
1. History:
A. Relevant factor in the history:
a. maternal age, increased risk with age especially trisomies
(13,18,21)
b. Congenital abnormalities in one or more of the existing children
c. Family Hx of congenital abnormality in either parent
d. previous still birth
e. Hx of recurrent 1st trimester recurrence miscarriage
f. Cousin marriage

5. B. Features on current pregnancy:
a. Drug intake (antiepileptic, warfarin, alcohol, smoking)
b. Radiation exposure
c. Maternal medical disorder like diabetes & cardiac
disease
d. Uterine fundus larger than dates e.g polyhydramnios,
macrosomia & twin pregnancy
e. Fundal height smaller than dates e.g oligihydramnios,
IUGR
f. Abnormally less or weak fetal movement
g. Fetal malpresentation
h. Feature suggestive of viral infection in early
pregnancy e.g flue like symptoms

6. C. Ultrasonography: it has been evaluated as a
screening tool in all 3 trimesters
At 10-14 weeks: NT measurement (a
measurement equal or more to 2.5mm is
strongly associated with chromosomal
abnormalities
At 18- 20 weeks: for screening of structural
congenital abnormalities

7. D Maternal Blood Test:
a. Maternal Alpha feto protein levels used for
screening of NTD like anencephaly,
meningomyelocele & open spina bifida defect. It
is taken between 15-20 weeks of gestation & cut
off value of 2-2.5 multiple of median is used.
b. Free fetal DNA can be extracted from maternal
blood to determine blood of fetus, sex of fetus,
X-linked disorders and aneuploidies

8. Maternal Blood Test
MSAFP is not specific to NTD & levels raised in case of following:
i- miscalculated gestational age
ii- multiple pregnancy
iii- threatened miscarriage
iv- IUD
V- NTD
vi- anterior wall defect
vii- teratoma
viii- miscellaneous anomalies
So women found to have increase MSAFP levels are then subjected
to a detail USG examination

9. Screening for Down Syndrome
• In UK NICE has recommended that all female should be offerred screening for Down Syndrome as a
part of routine antenatal care, it is alsp recommended that the screening test offered should have
atleast a 75% detection rate & <3% false + rate.
Several tests can be offered for the screening of Down Syndrome:
a. NT: a 1st trimester (11-14 weeks) NT together with the maternal age
b. Quadruple test: in 2nd trimester (14-20 weeks) measurement of MSAFP, unconjugated
estriol, beta HCG & inhibin A together with the maternal age
c. Combined test: Late 1st trmester (10-14 weeks) based on NT measurement with B HCG,
pregnancy associated plasma protein A & maternal age
d. Integrated Test: the integration of different screeening markers measured at different
stages of pregnancy into a single test result
e. USG markers: Nuchal skin edema, Short femoral & humeral length, choroid lexus cyst,
bilateral renal pelvic dilatation, echogenic bowel & hyper echoeic foci in fetal heart
DEFINITIVE DIAGNOSIS OF DOWN SYNDROME requires a prenatal diagnosis ny invasive tests

10. •PRETEST COUNCELLING:
prior to the test the clinician should
discuss with women what option would be
available to her if the test result shows that the
fetus is affected in this condition. There is no
point doing any invasive test if it will not be of
any benefit to the mother or baby

11. INVASIVE TEST:
AMNIOCENTESIS:
aspiration of amniotic fluid. Amniotic fluid & cells are cultured which
takes 3 weeks by the time results is available. It is used for estimation of
bilirubin level for detection of hemolytic disease like RH iso immunization
Also analyzed for estimation of AFP levels & presence of Acetyl choline
esterases for diagnosis of NTD. Amniotic fluid cells are also used for
karyotyping & for detection of chromosomal abnormalities & viral infection
like CMV.
RISKS ASSOCIATED WITH AMNIOCENTESIS:
a. Pregnancy loss 1%
b. leakage of amniotic fluid leading to oligohydramnios  RDS
c. Fetal trauma  needle prick to the baby

12. CHORIONIC VILLOUS SAMPLING
is a procedure of collection of piece of placental tissue containing
chorionic villi, the cells are then examined for diagnosis of congenital
abnormalities
Done between 11-14 weeks
INDICATIONS FOR CVS:
a. DNA analysis hemoglobinopathies, hemophilias, muscular dystrophy,
cystic fibrosis, A1 antitrypsin deficiency
b. Chromosomal abnormalities
c. In born error of metabolism
CVS is associated with high risk of miscarriage (1-2%) as compared to
amniocentesis

13. CORDOCENTESIS
is performed when fetal blood is needed or when a rapid full
culture for karyotyping is needed. Can be performed from
about 20 weeks of gestation.
INDICATIONS :
a. Prenatal diagnosis
b. Fetal assessment: red cell alloimmunisation, hydrops
fetalis, viral infections, platelet alloimmunisation
RISKS OF CORDOCENTESIS:
a. Bleeding from site of puncture
b. Cord hematoma
c. Fetal bradycardia
d. Fetal death

14. FETAL SURVEILLANCE
is broadly classified into 2 groups.
Screening tests Specific tests
a. Fetal movements a. cardiotocography
b. symphysiofundal height b. USG
c. BPP
d. doppler USG

15. SCREENING TESTS
1. Fetal movements: normal fetus moves >10
times/hour. FM is greatest between 28-30
weeks
a. Cardiff count to 10 kick chart: mother is
asked to start counting fetal movements at 9
am and record the time when she completes
10 movements, if 10 movements not felt by 9
pm that is 12 hours further investigation are
required

16. SCREENING TESTS
b. Other methods:
daily counting of fetal movements at the same
time for 1 hour, preferably in evening when fetus is most
active. If fewer than 10 movements are appreciated
counting is continued for another one hour & if fewer
than 10 movements in 2 hours patient should contact
physician.
Counting fetal movements daily 2-3 times daily
for 30 mins. With this approach further evaluation is
recommended if there are fewer than 4 strong
movements in a 30 min period.

17. ADVANTAGES OF FETAL MOVEMENT
• Cheap method of fetal monitoring
• It allows continuous observation of fetal well
being at home
• It involves mother herself in care of fetus
• It has been reported to reduce the peri natal
mortality rate

18. DISADVANTAGES OF FETAL
MOVEMENTS
• Increases maternal anxiety
• Increase frequency of hospital admission
• Use of CTG
• C section

19. SYMPHYSIOFUNDAL HEIGHT
Fetal growth as well as well being can be judged
from assessment of SFH. It is simple method of
assessing altered growth but it’s a crude method
having low positive predictive value.

20. SPECIFIC TESTS
• CARDIOTOCOGRAPHY:the record of fetal cardiac and
uterine behaviour on a paper is called a Cardiotocograph & the
procedure is called cardiac tocography
• a CTG carried out in antenatal period in absence of any stress is
called non stress test
• 4 observations are important in the interpretation of CTG:
a. Baseline fetal heart rate
b. Fetal heart rate variability
c. Acceleration
d. Deceleration
All 4 variables are effected by oxygen deficiency making it a
useful tool for diagnosis of antepartum fetal hypoxia

21. REACTIVE CTG
Is one with baseline FHR of 110-160 beats/min.
fetal heart rate variability of 5-25 beats/min at
least 2 acceleration of > 15 beats/min over 15-
20 min & no deceleration

22. Ultrasound
• Fetal growth asssessment by fornightly
ultrasound

23. BIOPHYSICAL PROFILE
Variable included in BPP:
1. Non stress test (CTG) for 20 mins 2
2. Fetal breathing movement 2
3. Gross fetal movements 2
4. Fetal tone 2
5. Amniotic fluid volume 2
Total score 0-10
If score 8-10 …… satisfactory
If score 6 …… repeat assessment
If score 4 …. Expedite delivery
Most important tools of BPP are CTG & amniotic fluid volume

24. DOPPLER Ultrasound
• Umblical artery flow, velocity, wave forms:
a. Blood flow through umblical artery gives a typical low
resistant pattern demonstrating continuous forward
flow during systole as well as dystole.
S labelled as peak systolic flow
D as end diastolic flow
Low S/D ratio means there is low resistance of flow
Increase ratio means increase flow with further increase
in resistance in the placental blood vessel abscent end
diastolic flow occurs which further leads to reverse
diastolic flow

25. DOPPLER Ultrasound
• Increase S/D ratio & absent diastolic flow
shows fetal hypoxia so intensive fetal
monitoring is required,
• Reverse end diastolic flow may cause fetal
demise within 24-48 hours so need immediate
delivery.

26. THANK YOU