The principal goal of prenatal diagnosis is to provide risk information to families to help them make informed choices during pregnancy. Potential benefits include early reassurance for normal results, risk information for couples who may terminate affected pregnancies, and time to prepare for birth of an affected child. Nuchal translucency screening between 10-14 weeks gestation is currently the most powerful first trimester marker for detecting Down syndrome, though an increased measurement can also indicate other genetic syndromes or developmental delays. Management depends on gestational age at diagnosis, presence of other anomalies, karyotype results, infection studies, and parental views, and may involve pregnancy termination, fetal testing, or delivery planning.

1. •Principal goal of prenatal diagnosis is to supply information to at risk families so they
can make informed choice during pregnancy.
•Potential benefits of prenatal diagnosis are
1) early reassurance to at risk families if results are normal.
2) Risk information to couples who would not have child without defects.
3) Allowing couples to prepare for the birth of an affected child.
4) Risk information to couples for whom termination is an option
4) Risk information to couples (From callens 5th
First Trimester Screening
Screening methods
age-
1.Age of mother Risk of Downs syndrome and any
aneuploidy increases with age.
2.Women with age 35 years and singleton pregnancy and
age of 31 years with twins (dizygotic), put women into
high risk group of fetal aneuploidy.
3..
4.
5.Nuchal translucency.
6.Nuchal Translucency(NT) refers to the normal subcutaneous fluid filled space
between the back of the neck and underlying skin.
7.Single most powerful marker available today for differentiating Downs syndrome
from euploid pregnancy in 1st
trimester.
8.NT is not specific for aneuploidy its also increased in
9.CHD
11.Genetic syndrome
11.Abnormal or delayed development of lymphatic.

2. 12.Time – 10 to 14 weeks ( CRL of 36 to 84mm).
13.
14.
15.. If NT is ≥ 3.5 mm significant risk of aneuploidy ----appropriate to perform invasive
testing..

3. 16.

16. Soft marker by ultrasond

31. 

Depend on
1.gestational age at diagnosis
2.presence of other anomalies
3.results of the karyotype
4.infectious studies
5.views of the parents.


If the diagnosis is made prior to
fetal viability: patient may
consider pregnancy termination.
If the diagnosis is made after
viability or the couple chooses to
continue with the pregnancy: the
following procedures can be
performed (depending on the
circumstances)
I. isolated or associated with
other congenital anomalies.

32. Isolated ventriculomegaly is
associated in 3% of cases with
chromosomal anomalies.
If associated with other defects,
this figure rises to 36%.
The most common associated
anomaly (25-30%), is spina
bifida, followed by other defects
(CNS, renal, GIT) in 7-15%
1.Fetal echocardiogram to check
for cardiac anomalies
2.Amniocentesis to analyze the
fetal karyotype
3.Maternal testing to check for
recent or current infections
4. Genetic counseling: X-linked
recessive aqueductal stenosis
carries a 1 in 4 risk of recurrence
for future pregnancies and a 1 in

33. 2 risk for male fetuses.
Cerebellar agenesis with
hydrocephalus is rare but may
also be sex-linked and thus have
a similar recurrence risk.
II. Degree of ventriculomegaly
Mild: > 10 mm cortical thickness +
normal BPD Severe: < lOmm cortical
thickness + abnormally increased
BPD
Atrium of lateral ventricle: <10
mm Mild: 10-15 mm Severe: >15
mm


Timing of delivery 1.
Associated with other defects or
chromosomal abnormalities:
couple should be counselled
about termination of the

34. pregnancy 2. No clear indication
for preterm delivery if the
hydrocephalus is rapidly
progressive prior to fetal lung
maturity {respiratory distress
syndrome, which would delay
shunt placement, could actually
worsen the final outcome}. 3. If
the hydrocephalus is rapidly
progressing and delivery is
necessary prior to lung maturity:
corticosteroids {decrease the
severity of RDS}.


Mode of delivery
1.CS: a. isolated disease and
moderate to severe
macrocephaly {facilitate the
atraumatic delivery of the
enlarged fetal head}. b.
Macrocrania is present

35. 2. Vaginal delivery
a.vertex presentation and has
only mild macrocephaly.
b.Associated anomalies that are
either incompatible with life or
associated with the severest
forms of neurologic dysfunction
e.g., alobar holoprosencephaly,
hydrancephaly, or thanatophoric
dysplasia with cloverleaf skull),
cephalocentesis and subsequent
vaginal delivery are an
acceptable alternative to
cesarean delivery.


Cephalocentesis prior to
delivery –
This is a destructive procedure.

36. done to reduce the cranial size
and potentially allow for vaginal
delivery.
This is associated with
significant fetal/neonatal
morbidity and is indicated only in
cases where the prognosis is
thought to be extremely poor.
performed by passing a 14- to
18-gauge needle
transabdominally or
transvaginally under US
guidance, and removing
sufficient cerebrospinal fluid to
allow overlapping of the cranial
sutures