Can anyone advice me on something. I had my 20 week scan on Friday where I thought everything was OK. I have been booked for another scan at 28 weeks, this is due to them detecting a single soft maker on my 20 week scan. My midwife told me that my triple test come back at low risk so have no need to worry. What could this single soft maker mean?

A soft marker means there is a possibility of a concern. A number of things, or "markers" are checked on a scan, and once in awhile something may look a bit suspicious so that they will want to investigate further. The triple test tends to have a somewhat high false positive rate, so if that is showing no concern, along with just single marker, it adds to the likelihood that all is well. Certainly they will want to make sure, hence the additional scan when baby is a bit more developed.
Given all of that, obviously you worry... but try to think of it as more of a precaution than a definite problem at this point.

A soft marker means there is a possibility of a concern. A number of things, or "markers" are checked on a scan, and once in awhile something may look a bit suspicious so that they will want to investigate further. The triple test tends to have a somewhat high false positive rate, so if that is showing no concern, along with just single marker, it adds to the likelihood that all is well. Certainly they will want to make sure, hence the additional scan when baby is a bit more developed.
Given all of that, obviously you worry....but try to think of it as more of a precaution than a definite problem at this point.

Thanks!
I asked at the hopital today and they said I am at low risk my results showing - 1 in 12000. The single marker was a renal pelvis dilatation of 3.4mm. I understand that this is concerning the kidneys. Do you know what the national guidelines are for RPD. Is 3.4mm high then?

A measurement of 3.4mm at 20 weeks is fairly small and just under the lower end of the range of concern which I believe is roughly 4mm-8mm (higher than that becomes even more of a concern). In the vast majority of cases at that size, it will sort itself out during pregnancy or soon after birth. The later scan will double check and, if there was still a concern, they would check again after birth.

A measurement of 3.4mm at 20 weeks is fairly small and just under the lower end of the range of concern which I believe is roughly 4mm-8mm (higher than that becomes even more of a concern). In the vast majority of cases at that size, it will sort itself out during pregnancy or soon after birth. The later scan will double check and, if there was still a concern, they would check again after birth.

Thanks Doula for your advice. Can you tell me what my result in the combined test means. My age related risk is 1 to 1100 and my actual result is 1 to 12000. Do results go up in stages for everyone or is every result different for each person depending on what they find on the NT scan and blood test? Thanks again.

You have an initial "risk" based on your age, any health concerns, etc... so right there numbers will vary from person to person from the start, and that will be adjusted, up or down, with what you get as test results. So you could have someone in their early-20's starting with a pretty low risk, but some markers are noted and their risk jumps higher... and someone in their early-30's starting with a bit higher risk (just due to age), but no concerns are shown on the tests so their risk drops.