Amniocentesis

Question 1

rates of loss with CVS

Answer 1

Transabdominal approach 0.2%
Transcervical approach 0.5%
higher risk if cannula method (3% vs forcepts)

Question 2

risk of pregnancy loss with amnio and CVS

Answer 2

pooled ratio 0.11% for amnio
0.22% CVS
in general additional risk of miscarriage is quoted 0.5%

Question 3

risks of amnnio/ CVS

Answer 3

risk of failed rapid cell culture 1-2%
risk of cell culture failure: -.5%
risk od need for repeat procedure 6%
risk of contamination with maternal cells 1-2%
risk of bloodstained sample (amnio) 0.8%
risk of placental mosaisism (CVS) 2%

Question 4

how many amnios do you need to do/ supervise a year to be competent

Answer 4

20

Question 5

when do you need to review practice with amnio loss

Answer 5

if >3% loss/ year

Question 6

risk of loss is how many times higher in early vs midtrimester amnio

Answer 6

9x (1.8% vs 0.2%)

Question 7

Risk of PTL if third trimester amnio between 34-37 weeks

Answer 7

4-8%

Question 8

Risk of PTL if third trimester amnio befor 34 weeks

Answer 8

3-4%

Question 9

risk of blood stained sample with third trimester amnio

Answer 9

5-10%

Question 10

cell culture failure in third trimester amnio

Answer 10

9.7%

Question 11

risk of needing multiple needle insertions in third trimester amnio

Answer 11

5%

Question 12

cell culture failure after amnio between 36-40 weeks

Answer 12

40%

Question 13

risk of transmission of HIV during amnio if not on HAART

Answer 13

2.3% (0% if on ART)

Question 14

risk of hep B transmission in amnio

Answer 14

OR 4.76 (17.4% vs 4.2%) if copies >6.99 log