I had one at about ten weeks.

My GP said best NOT to do but it was quite a while (6 years) since my last one. I asked my GP whether there was any treatment that could be done while pregnant if the test was positive and she said no, so there didn't seem any point having one then stressing if the results were bad if I couldn't have any treatment.

Then when I saw my ob, he said GPs don't like to do them but they are quite safe. He also said there WAS treatment that could be given and best to know one way or the other. He said he does them all the time and GPs are just nervous about it because they don't do them so often on pregnant women.

So ... not sure what to advise you. If you have an ob then I'd probably get one done by him/her instead of the GP if it makes you feel more comfortable about the whole thing.