Langdon Down London 1866 Subgroup of idiots Down syndrome mongolian people Downs theoryretrogression of ethnic type Darwins contemporary scientific reasoning for evolution ID: 933177
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Slide1
E.Keshavarz MD
First trimester screening
Slide2Langdon Down (London 1866)
Subgroup of idiots…. Down syndrome(
mongolian
people)
Down’s
theory:retrogression
of ethnic type
(Darwin’s contemporary scientific reasoning for evolution)
Theory was not true but 100 years later:
Skin:dirty
yellowish tinge skin and is deficient in
elasticity,giving
the appearance of being too large for the body
Slide31866:congenital,dating from intrauterine life
1909:association with maternal age
1914:no increased within families
1914:syphilis,TB,epilepsy,alcholism,insanity,nervouse instability , endocrine abnormalities(thyroid , adrenal ,
pitiutary
, thymus)
1932:diz.t:un.equally
monoz.t:equally
transmission from mother to the baby
*** 1934:unequal migration of chromosomes during cell division…
trisomy
Slide41960:familial Down syndrome
translocation(15:21),no
trisomy
1961:mosaism type of Down syndrome
mosaism
of normal and
trisomic
cells
1966:karyotyping of cultured amniotic fluid cells
Slide5Whole or a segment of long arm of
ch
21 is in three copies:
1-non
dysjunction
(95%)
2-translocation
3-mosaicism
1991:95% of non
dysjunction
: maternal origin
Slide6Only amniocentesis !
1-private health care system:>35 y
was 5% now 10% and more!
2- NHS:5% pregnant mothers…>37-40 y
only 30% of
trisomy
21 babies !
Slide7Aneuploidy Screening
Slide8CRL measurement
CRL measurements can be carried out
transabdominally or
transvaginally.
A
midline sagittal section
of the
whole embryo
or fetus should be
obtained.
Slide9NT measurement
- CRL:45-84 mm (11w-13w 6d)
- TAS(95% success)=TVS(other 5%)
- Waiting for spontaneous fetal movement, asking the mother to cough, tapping the maternal abdomen(amnion membrane!)
Slide10NT measurement
Good work after 80-100 sonography and at least 10 min
Study on 100,000 cases:normal:1.2 (11w) to 1.9(13w 6d)
abnormal:above the 95
th
centile(>=3mm)
Slide11Umbilical cord around the fetal neck( 5-10
%)
Slide12Slide1311-14 week sonography
Trisomy 13 and Turner:
mild growth restriction
tachycardia(delay maturation of
para.s
)
Trisomy 18 and triploidy:
mod-severe growth restriction
bradycardia
(early onset of growth restriction)
Trisomy 21:
normal growth
mild increased in FHR (HF and compensatory increased FHR)
Slide14Slide15Maternal Serum Biomarkers
Type
of aneuploidy
Free
β-
hCG
PAPP-A
Trisomy 21
↑↑
↓↓
Trisomy 18 & 13
↓↓
↓↓
Sex chromosomal anomalies
Nl
↓↓
Diandric triploidy
↑↑↑
↓
Digynic triploidy
↓↓↓
↓↓↓
Slide16Down screening
Triple test at 11w – 13w 6d
detection rate:90%
Maternal serum biochemistry 16w
detection rate:60%
Combination of them:90%+(60% of other 10%)
detection rate :96%
Slide17PAPP-A :lower in smoking and IVF
Higher in black(60%)
Free BHCG is more in 21 (than 18 and 13) specially in W13
PAPP-A is more in 21 (than 18 and 13) specially inW11
The difference is more in PAPP-A than Free BHCG
Maternal serum biochemistry screening in W11 is better than W13 and also better in W10 than W11
W12 NT+W12
MSB:detection
rate 84%
W12 NT+W10
MSB:detection
rate 94%
Slide18OSCAR
New methods of biochemical testing within 30 min(
time-resolved-amplified-
cryptate
-emission
)+ NT at the same time:
O
ne
S
tep
C
linics for
A
ssessment of Risk
Slide19Maternal age+NT+FHR+FreeBHCG+PAPP
-A
Slide20New US markers
1-NB
2-Facial angle
3-Ductus
venusus
flow
4-Trichospid flow
1-NB
2-DV PI
3-TR
Slide21Aneuploidy Screening
Method of screening
Detection
Rate (%)
False Positive
Rate (%)
MA
30
5
MA + fetal NT
75-80
5
MA + serum free
β-
hCG & PAPP-A
60-70
5
MA + NT + free β-hCG & PAPP-A (combined test)
85-95
5
Combined test + NB
or
TV flow
or
DV flow
93-96
2.5
Slide22Trisomy 21 Screening
Method of screening
Detection
Rate (%)
False Positive
Rate (%)
Combined test
90
5
Combined test + NB
92
3
Combined test + FMF Angle
92
3
Combined test
+ DV Flow
96
3
Combined test + TV Flow
96
3
Combined test + 2 additional markers
94
2
Combined test + 3 additional markers
95
2
Combined test + 4 additional markers
96
2
Slide23NB
If NB is absent in 11 to 12 week:
Patients are
rescanned after 12
week and action is only taken at that point if there is persistence of the absence of the nasal bone.
Slide24Increased NT/ Abnormal reverse a wave in ductus
In addition, there is an increased risk for cardiac defects and therefore such patients should have a follow up specialist fetal cardiac scan.
Slide25Slide26Slide27Additional US Markers
Classic Markers
Newer Markers
Minor
Markers
(Less important)
Nasal Bone (NB)
Fronto-Maxillary Angle (FMF angle)
Ductus Venosus (DV) Flow
Tricuspid Valve (TV) Flow
Ductus Venosus Pulsatility Index for Veins (DV PIV)
Hepatic
Artery Pulsatility Index (HA PI)
Maxillary length
Ear length
Femur & humerus length
Single umbilical artery
Megacystis
Exomphalos
Choroid plexus cysts
Pyelectasis
Cardiac echogenic foci
Slide28Preeclampsia
Slide29Preeclampsia
Preeclampsia, which affects about 2% of pregnancies, is a major cause of
perinatal
and maternal morbidity and mortality
The likelihood of developing preeclampsia is increased by a number of factors in the maternal history, including
Afro-Caribbean race,
nulliparity
, high body mass index and personal or family history of preeclampsia
. However, screening by maternal history may detect only about
30%
of those that will develop preeclampsia for a false positive rate of 5%.
Slide30measurement of the uterine artery
pulsatility
index (PI) at 11-13 weeks' gestation in combination with
maternal history
(inc)
mean arterial pressure
(inc)
serum PAPP-A
(
dec
…>inc)
placental growth factor (PLGF) (dec…>inc)
The factors in the maternal history that appear to make a significant independent contribution to the preeclampsia risk assessment included maternal BMI, age, ethnicity, smoking, and parity.
Slide31early rather than late preeclampsia is associated with an increased risk of
perinatal
mortality and morbidity and both short-term and long-term maternal complications.
Combination of the above mentioned risk factors was shown to predict
90%
of early preeclampsia,
35%
of late preeclampsia, and
20%
of gestational hypertension.
This compares favorably with screening based on maternal history alone where only
30%
of early and 20% of late preeclampsia are predicted for a 5% false positive rate.
Slide32Slide33Gender Determination
Slide34Gender Determination
Deciding
whether to carry out
prenatal
invasive testing
in pregnancies at risk of
sex-linked
genetic
abnormalities
Just necessary in
male
fetuses
Angle between
the
genital tubercle
&
a
horizontal line
through the lumbosacral skin
surface:
Male
if
> 30
°
Female
if
Parallel or
C
onvergent
(<
20°)
Slide35Test Properties
Test accuracy:
11 wks. 70.3%
12 wks. 98.7%
13 wks. 100%
In
the
male
fetuses, there is a significant increase in the angle of the genital tubercle from the horizontal with CRL increment
Final
decision
should
be undertaken
only
after
12
weeks
Gestational
Age
Male
(Wrong
assignment)
Female
(Wrong assignment)
11 wks
56%
5%
12
wks
3%
0%
13
wks
0%
0%
Slide36Thank you