Do i go for amniocentesis?

I am trying to make a decision and don't know what to do. I am 13 weeks tomorrow and I am trying to decide whether or not to go ahead with an amniocentesis test.

My sister had downs syndrome and died very young, I really don't think I could go through that. Also my neighbours have a son with downs, when the parents died he was sent to a home because his brother couldn't take care of him full time.

At the same time the scan can risk the babies life. They say there is a 1:150 chance of miscarriage but that this does not take into account the variance in how many weeks pregnant you are or experience of person doing the test.

My mother had the scan with me and my sister-in-law had the scan and babies were all fine. My midwife had it as well. She in fact said it would be ok but now the expert doesn't think so. I have a not test appointment withthe expert on 10 September so I will have to decide soon.

Also if you get the scan you get better care. I live in Edinburgh and we only get one scan at 12 weeks. nothing else but if you get the amnio they give you your 20 week scan as well, which would be really good because this can pick up so much.