Early pregnancy investigation
1. Biochemical
2. Biophysical
3. Cytogenetic
1. Biochemical
Maternal serum alpha fetoprotein (MSAFP), produced by yolk sac and fetal liver.
AFP highest level in serum and amniotic fluid reached; 13 week after it decreases.
Low level of maternal serum found in trisomy (Down syndrome), gestational trophoblast disease.
If AFP reached peak around 32 weeks, then
1.Wrong gestation age
2.Open neural tube defect (NTDs)
3. Rhisoimmunization
4. Renal anomalies
5. IUFD (intrauterine fetal demise)
Test to done between 15-20 weeks.
2. Triple test
Triple marker test include;
MSAFP
HCG
UE3 (unconjugated oestriol)
Done in 15-18 weeks
Low level of MSAFP and UE3 and high hCG in second trimester indicates down syndrome.
3. Inhibin A test
Made by placenta during pregnancy and corpus leuteum.
Raised serum level of inhibin A; fetus with down syndrome.
4. Screening
1. First trimester screening
Increase hCG, decrease MSAFP, decrease PAPP (pregnancy associated plasma protein).
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Can detect trisomy
2. In second trimester screening
Triple test (decrease MSAFP, decrease UE3, increase hCG).
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Can detect trisomy
3. Quadruple test
(Decrease MSAFP, decrease UE3, increase hCG, increase inhibin A).
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Can detect trisomy 21
5. Prenatal genetic diagnosis
1.Amniocentesis (14-16 weeks)
Early (12-14 weeks)
2. CVS (chorion villus sampling)
3. Cordocentes
1.Cytogenetic analysis
Diagnose of chromosomal anomalies.
G-banding (karyotype)
Trisomy 21
Turner syndrome
2. DNA analysis
To diagnose single gene disorder
Cystic fibrosis
Tay Sachs disease (nerve cells in the brain and spinal cord)
3. Biochemical analysis
Amniotic fluid AFP level increase; open neural tube defect.
Chorionic villus sampling (CVS)
Between 10-12 weeks
Transcervically (10-20weeks)
Transabdominally (20 weeks to term)
Limb reduction defect (LRD) are high; when CVS perform less than 10 weeks of gestation.
Anti-D immunoglobulin IM 30 µg administer following procedure to Rh negative mother.
Cordecentesis (18-20 weeks) ;Fetal blood sampling
Percutaneous umbilical cord sampling
Perform under local anaesthesia.
22G spinal niddle 13cm length inserted through maternal abdominal and uterine wall inder ultrasound guidance.
Puncture the umbilical vein approx 1-2cm from placental insertion.
0.5-2ml of fetal blood collected.
Invasive procedures may lead;
Abortion
Preterm labour
Intrauterine fetal death
Cord haematoma formation
PROM
Infection (Amnionitis)
Anti-D immunoglobulin 100 µg give to The negative woman.
Haematological;
For fetal anaemia
Bleeding disorder
Rhesus disorder
Fetal infection; Toxoplasmosis
Viral infection
Fetal blood gas and acid base status; in fetal growth restriction
Fetal therapy; Blood transfusion, drug therapy
Biophysical marker;
Ultrasonography examination of fetus in early (10-14week pregnancy)
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Detect fetal anomalies
Crown-Rump length (CRC) smaller than gestational age (Risk of chromosomal anomalies).
Nuchal translucency (NT); increase NT appearance of collection of fluid under skin behind the fetal neck done at 20-14 weeks.
(Detection with many chromosomal abnormalities)
Absence of nasal bone (NB) on USG at 10-12 weeks (fetal down syndrome).
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