QuestionSBA
QuestionChoice
These are screening blood tests which can help inform whether invasive test is needed. AFP and PAPP-a are typically lower in Down's Syndrome pregnancies and serum HCG is typically higher.
10035956
e
AFP, PAPP-a and serum HCG
QuestionChoice
This is a screening test which measures the thickness of a fluid-filled space at the back of the baby's neck during the first-trimester ultrasound. An increased translucency measurement may indicate a higher risk of certain chromosomal abnormalities, prompting further diagnostic testing such as chorionic villus sampling (CVS) or amniocentesis for confirmation.
10035955
d
Nuchal translucency scan
QuestionChoice
Later in pregnancy, this may give evidence related to congenital heart defects related to Down's Syndrome, but would not be diagnostic in and of itself.
10035954
c
Echocardiogram
QuestionChoice
This is correct. This an invasive test to definitively diagnose Down's Syndrome by taking a small sample of placental tissue (chorionic villi) from the uterus, usually through the cervix or the abdomen. It is performed between 11 and 14 weeks.
10035952
a
Chorionic villous sampling
QuestionChoice
This is an invasive test to definitively diagnose Down's Syndrome by inserting a thin needle through the abdomen into the uterus to withdraw a small amount of amniotic fluid surrounding the foetus, which is then analysed. It is performed after 15 weeks of gestation.
10035953
b
Amniocentesis
Concept
Chapter
2693
6172
Down's Syndrome
Topic
333
Obstetrics and Gynaecology
19594
Chorionic villus sampling is an invasive procedure used for definitive prenatal diagnosis of Down's Syndrome between 11 and 14 weeks of gestation.
A 45-year-old multigravida presents to the antenatal clinic worried about the risk of her child developing Down’s Syndrome. She would like a definitive test performed. She is 13 weeks pregnant.

Which of the following is the most appropriate investigation to order?
a