8B) Antenatal Care - Invasive testing

Question 1

What percentage of pregnant women are offered invasive testing?

Answer 1

5%

Question 2

What is the most common type of invasive testing?

Answer 2

Amniocentesis

Question 3

When can invasive testing be performed?

Answer 3

Amniocentesis usually after 15 weeks gestation.
CVS 11-13+6.

CVS cannot be performed before 10 weeks.
Amnio prior to 14 weeks associated with increased fetal loss, talipes and respiratory morbidity.

Question 4

Risk of miscarriage after invasive testing

Answer 4

1%

Question 5

Technique for invasive testing

Answer 5

• Ultrasound guidance reduces blood staining from 2.4 to 0.8%
• Avoid transplacental passage of amniocentesis needle
• Maximum outer gauge needle size 0.9mm (20 gauge)

Question 6

Competency rules for invasive testing

Answer 6

Must perform at least 30 per year.

Review competence if fetal loss in more than 4/100 consecutive amniocentesis or more than 8/100 consecutive CVS.

Question 7

Who should have anti-D after invasive procedures?

Answer 7

All Rh NEG people!