First two DC fine, but didn't do bloodwork.
DC3 was 1 in 34 thanks to PAPP-A of 0.21MoM and 1.89MoM bHCG. He has typical chromosomes after I waited it out for a late "safe" amnio at 32 weeks. I was 34.
This DC, I'm 37 now, was 1 in 5 thanks almost entirely to the bloodwork, although the nuchal was borderline high (but bloodwork only would have been 1 in 16) Normal PAPP-A, but 5.43MoM for the bHCG. FMC say the high bHCG is most probably due to the bleeding I had. According to Harmony she has typical chromosomes and all the scans have checked out so far (am now 28ish weeks)
One thing I would suggest if your midwife/consultant hasn't already is to make sure you get a growth scan at 28-32 weeks as low PAPP-A and high bHCG can be indicative of potential placenta issues.. rare, but a higher risk than usual. So long as you have the scan, if there are any issues they can consider early delivery, so the overall long term risk to the baby is low. But not having that scan and there is an issue could potentially lead to problems.
Hang on to the fact your baby is 85% likely to have typical chromosomes! And from my experience of hanging around on forums like these (and over on Babycentre where there is quite a high traffic one devoted to amnios etc) that it was very rare indeed for a "bloods only" high risk screening to result in a baby with non typical chromosomes. Usually there was something else seen on the scan, or a noticeably thickened nuchal fold.
Good luck with the wait and your result!