All notes/flashcards obstetrics

Amniocentesis

• What is the main risk of amniocentesis? Miscarriage, 0.5%, higher risk in multiple pregnancy

• When can amniocentesis be performed? From week 15 onwards

• What does amniocentesis look at in the fluid? Foetal cells

• Describe the amniocentesis procedure. Local anaesthetic, then under ultrasound guidance, a needle is passed through the mother’s abdominal wall and into the amniotic sac. The needle should not pass through the placenta unless absolutely necessary.

  A small amount of amniotic fluid is taken, and fetal cells are sent for karyotyping and/or PCR.

  Note: Rhesus-negative women will need Anti-D immunoglobulin after the test.

• What is the most common indication for amniocentesis? A “high risk” result from a first trimester screening test, or a previous pregnancy affected by a genetic condition.

• What does amniocentesis look for? Down’s syndrome, Edward’s syndrome and/or Patau’s syndrome

Chorionic villus sampling

• When can CVS be performed? 10-13+6 gestation