E.Keshavarz MD First trimester screening - PowerPoint Presentation

Slide1

E.Keshavarz MD

First trimester screening

Slide2

Langdon 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

Slide3

1866: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

Slide4

1960: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

Slide5

Whole 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

Slide6

Only 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 !

Slide7

Aneuploidy Screening

Slide8

CRL measurement

CRL measurements can be carried out

transabdominally or

transvaginally.

A

midline sagittal section

of the

whole embryo

or fetus should be

obtained.

Slide9

NT 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!)

Slide10

NT 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)

Slide11

Umbilical cord around the fetal neck( 5-10

%)

Slide12

Slide13

11-14 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)

Slide14

Slide15

Maternal Serum Biomarkers

Type

of aneuploidy

Free

β-

hCG

PAPP-A

Trisomy 21

↑↑

↓↓

Trisomy 18 & 13

↓↓

↓↓

Sex chromosomal anomalies

Nl

↓↓

Diandric triploidy

↑↑↑

↓

Digynic triploidy

↓↓↓

↓↓↓

Slide16

Down 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%

Slide17

PAPP-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%

Slide18

OSCAR

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

Slide19

Maternal age+NT+FHR+FreeBHCG+PAPP

-A

Slide20

New US markers

1-NB

2-Facial angle

3-Ductus

venusus

flow

4-Trichospid flow

1-NB

2-DV PI

3-TR

Slide21

Aneuploidy 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

Slide22

Trisomy 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

Slide23

NB

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.

Slide24

Increased 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.

Slide25

Slide26

Slide27

Additional 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

Slide28

Preeclampsia

Slide29

Preeclampsia

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%.

Slide30

measurement 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.

Slide31

early 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.

Slide32

Slide33

Gender Determination

Slide34

Gender 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°)

Slide35

Test 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%

Slide36

Thank you