Prenatal Diagnosis Flashcards

Flashcards to review key concepts in prenatal diagnostics.

What is the purpose of prenatal diagnostic tests?

To assess the health of the fetus, enable couples at risk of genetic disorders to have unaffected children, identify potentially important intrauterine treatment, plan for complications at birth, decide whether to continue pregnancy, and discover conditions that may impact future pregnancies.

What are the indications for prenatal diagnosis related to genetic risks?

Advanced maternal age, previous affected pregnancy, family history of a known genetic condition or congenital abnormalities, and either of the couple affected by congenital disorder

What are the indications for prenatal diagnosis beyond genetic risks?

Previous history of a pregnancy affected by congenital anomalies, maternal medical conditions, medications, congenital infections and abnormal ultrasound findings (soft markers)

What are non-invasive methods of prenatal diagnostics?

First trimester screening, maternal serum biochemistry, NIPDT (analysis of fetal cells in maternal blood), ultrasonography, echocardiography, Doppler sonography, preeclampsia screening, and pre-implantation diagnosis

What are invasive methods of prenatal diagnostics?

Chorionic villus sampling, amniocentesis, cordocentesis, and fetoscopy

What does the first trimester combined test involve?

Measures pregnancy-associated plasma protein-A (PAPP-A) and human chorionic gonadotropin (HCG) levels in blood, and includes a Nuchal Translucency ultrasound exam

What is the significance of cell-free fetal DNA (cffDNA) testing?

High sensitivity in detecting trisomy 21, where a negative test makes trisomy 21 very unlikely

What are the indications for cffDNA testing?

Age >35 years old, sonographic evidence of aneuploidy, previous pregnancy with trisomy, and positive triple test

What is Preimplantation Genetic Diagnosis (PGD)?

A reproductive technology during IVF cycle for couples at increased risk for chromosome abnormalities or specific genetic disorders.

What is Chorionic Villus Sampling (CVS)?

A prenatal test where a sample of chorionic villi is removed from the placenta for testing, either transcervically or transabdominally, after the 11th week of pregnancy

What are the disadvantages of Chorionic Villus Sampling (CVS)?

No AFP determination in amniotic fluid possible, and possible mosaic formation in the placenta affecting the information

What is Amniocentesis?

A procedure that takes a sample (15–20 ml) of amniotic fluid containing fetal cells after the 15th week of pregnancy

What are the diagnostic indications for Amniocentesis?

Chromosomal analysis, detection of inherited metabolic disorders, checking AFP levels to rule out neural tube defects, detecting fetal lung maturity, and measuring bilirubin levels to diagnose fetal haemolytic disease

What is the Cordocentesis procedure?

Puncture of the umbilical vein under ultrasound guidance, usually at its placental origin

What are the indications for Cordocentesis?

Assessment and treatment of red cell or platelet alloimmunization, assessment of congenital infections, assessment of fetal anemia, and unclear karyotyping from amniotic fluid

What is Fetoscopy?

An endoscopic procedure during pregnancy to allow access to the fetus, amniotic cavity, umbilical cord, and fetal side of the placenta, done during and after 18 weeks of pregnancy

What are the indications for Fetoscopy?

Clarification of suspected skin diseases (e.g., Epidermolysis and congenital Ichthyosis), and fetoscopically controlled therapy (e.g., laser coagulation for fetofetal transfusion syndrome)

What is required after a positive NIPT result?

Confirmatory invasive diagnostic testing.