1 Dr.Maysarah M. AL-Badran M.B.ch.B,C.A.B.O.G,F.I.C.MPrenatal diagnosis Dr.Maysarah M. AL-Badran M.B.ch.B,C.A.B.O.G,F.I.C.M

2 Prenatal diagnosis Identification of a disease before birth.Usually preceded by screening test,women with risk factor identified during screening may undergo diagnostic test.

3 Screening test Include:history:family hx,past obstetric hxmaternal biochemistry:Down syndrom U/S:anomaly scan at 18-22wk

4 Diagnostic tests High risk pregnancies Invasive and non invasiveInvasive:amniocentesis,CVS, cordocentesis. Risk of miscarrige

5 Non invasive prenatal diagnostic testsUS for structural abnormalities Viral serology free fetal DNA extracted from maternal blood to determine fetal blood group or the sex of fetus by PCR. Fetal RNA from maternal to detect aneuploidy.

6 Pre-test counselling Indication The procedure Risk,limitationsManagement options:continue or terminate pregnancy

7 Amniocentesis At or after 15 wk Additional risk of miscarrige 1%Earlier amniocentesis is more risk

9 Chorionic villus samplingAt or after 11 wk Additional risk of miscarrige 2% If performed before 10 wk:limb distruption and oromandibular hypoplasia Transabdominal 0r transcervical Confined placental mosaicim

11 Laboratory analysis Full culture for karyotyping:7-10 daysResult for common aneuploidy(trisomy21,18,13) take 48 hours by Fluorescence in situ hybridization(FISH)or Polymerase chain reaction(PCR) Tests for genetic disorders take varying time

12 Cordocentesis Around 20 wkGreater risk of miscarrige than amniocentesis and CVS(2-5%) When fetal blood is needed as in alloimmune thrombocytopenia or when a rapid full culture for karyotype is needed

14 Screening for Down’s syndromRisk increases with age. Quadriple test(14-20wk):B-hCG,α-fetoprotein,unconjugated estriol,inhibin A Nuchal transulency:11-14 weeks Combined test(11-14wk): NT,B-hCG,pregnancy associated plasma protein A(PAPP-A)

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16 Structural abnormalityNeural tube defects: Anencephaly&encephalocele can be detected on first trimester U/S Spina bifida:’lemon’&’banana’sign Can be prevented by folic acid 400Mg-----high risk 5mg

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18 Congenital heart defectsGenetic,maternal DM,viral inf.,lithium Screening by U/S &fetal echo.

19 Diagnosis of GIT Structural abnormalitiesGastroschisis: US detect 90% of cases,not associated with other abn. or chrom. abn. Follow up is required—>risk of IUGR & oligohydramnios. exomphalos:US detect 90% of cases,associated with chrom. Abn.& other structural abn.

20 Other methods of AN diagnosis3D & 4D ultrasound Fetal MRI:CNS abnormalities

21 THANK YOU