Question about miscarriage statistics

[corduroybear]

Apologies if this is insensitive - I hope not.

Do the statistics about miscarriage include miscarriages which have already happened but not been diagnosed? For example, if you have a 5% risk of miscarriage at 7wks (as one site I found says), does that include the risk of discovering a missed miscarriage/blighted ovum which occurred prior to 7wks, or is it just relating to miscarriages which have yet to happen (rather than be discovered)?

I know that it is just statistics, but I have a first scan in two days and am trying to calm my nerves.

They are cumulative and look forward: so the 5% means after 7 weeks, if a heartbeat is found, only 5% of women will subsequently lose the pregnancy. However do check the miscarriage association stats - most sites have it up to 95% success rate after 8 or 9 weeks.

The baseline at BFP depends on factors such as age, weight, health conditions etc'. In women without a prior medical condition it varies from 60%-80%. This would be about 4 or 5 weeks.

The most accurate information would probably be found here miscarriageassociation.org.uk - avoid googling, there is a lot of bunkum out their either scaring women or full of superstition.

...if the site is using it's own system I would be wary. The risk 'per scan' is not generally how it is viewed.

My understanding is that the stats refer to what happens at the scan eg for a 5% risk at 7 weeks, it means at 7 weeks, if there is a heartbeat and everything looks ok, then at that point there is only a 5% risk of miscarriage. Things that have already happened would be discovered at this scan and so those pregnancies would not fall into the 5% chance, if that makes sense.

The run up to a scan is a horrible thing, be gentle with yourself.

I'd say those stats include the missed miscarriages. The figure most often quoted is 15% of all established pregnancies, where there was a positive test after the point at which period has been missed. Drops to 3% if an 8 week scan is correct size for dates and HB seen, 1% if all is well at 12 weeks. I'd say the 15% includes those pregnancies that didn't develop beyond 6-7 weeks but not picked up as a MMC until 12 week scan, as well as those where the physical loss happened earlier.

Good luck for your scan. Whatever stats you quote, you have a very good chance of all being well.

Thank you.

I have yet to see a heartbeat (first scan) and although all my symptoms are getting stronger and in line with my other (successful) pregnancies, and despite having had no bleeding, I'm petrified of going in and there not being a baby or there being no heartbeat. But you're right: the odds are in my favour.