Ask your midwife - when i had my first visit at about 8 or 9 weeks my midwife asked if i wanted to have a private scan. I declined but had the test for downs and spina bifda and my result was 1:5000.
How far gone are you?? I wouldnt worry, im 20 and my consultant said the average is 1:1500. Im sorry to hear about your friend its just unfortuante that she is that 1, but if your midwife had any concerns she would have sent you for more tests. But ask about private tests if you are concerned...good luck
Lauren xXx