I don't think you ever quite feel safe... you worry in the first trimester about miscarriages, you worry in the second trimester about a healthy anatomy scan, you worry in the third about pre term labor, you worry about a healthy delivery, and forget it once they are born... you worry for them to remain healthy. Anyway, I know that's not what you were asking, but the truth is, you will now worry for the rest of your life. Lol.
Anyway back to your question. Overall, in general, the chances of a miscarriage after seeing a heartbeat (I think the main part of this statistic is seeing the heartbeat, not necessarily how many weeks you are) is about 5%. But you will obviously hear countless stories here from the people who were in that 5%, which of coarse is heartbreaking and I can't even begin to imagine what some people have been through. We all pray not to go through that ourselves, but there is no guarantee that any of us won't be in that 5% this time or with another pregnancy. But, I think once there has been a verified healthy heartbeat, you can breathe a little easier than if you haven't had that verification yet. Another piece to this is a healthy heartbeat, because some people will have seen a heartbeat, but it is slower than it should be, which explains some losses after a confirmation of a heartbeat.
You also have to take into consideration the reasons people miscarry vary greatly, so you can't always compare one story to another, if that makes any sense. First trimester losses are usually related to chromosomal abnormalities, progesterone deficiencies, or immune issues whereas later loses tend to be related to infection processes or an incompetent cervix. There are probably some unexplained cases as well, but just knowing how many weeks someone miscarried at doesn't tell the whole story and doesn't mean you are at risk of the same thing. Someone else brought up a great point- that these boards attract those of us who need support because we either struggled to get pregnant, or struggled to remain pregnant so these boards themselves probably don't necessarily paint an accurate story when it comes to statistics.
The first trimester is really tough and I know you have had quite a journey. I really hope this is your forever baby and hope in these next couple of weeks you can start to rest easy and enjoy this special time. Once you feel kicks, it gets less scary but we have a little ways for that yet. Just know you aren't alone, we all are worried about the worst.
For me, I worry less about a miscarriage after I have seen a heartbeat, but then I move right on to worrying about a healthy baby and a healthy pregnancy. Xx
