Blood Sac in pregnancy

[WishIWasSleeping]

Hi. Just looking for some info or advice really. I have a pregnant friend who's just 12weeks, has had some fairly heavy bleeding and so spoke to m/w, got scanned at 9w, heartbeat fine, no further info given. At 12w scan today (further bleeding mon&tue) she was told baby is fine, but there is a sac of blood below the baby and this is what's causing the bleeds. Has anyone heard of this before?
They have booked her in for another 5 scans during the pregnancy to monitor the baby and the sac. I'm presuming if the sac does grow they'll have to get it out or deliver baby, and if it doesn't the baby will squash it and she will just bleed more?!
Any advice welcome. Thanks.

I had this, 11, 13 and 15 week. They called it a subchorionic haemotoma. Its an accumulation of blood within the folds of the chorion (the outer fetal membrane, next to the placenta) or between the uterus and the placenta itself.

It sounds pretty much like what i had

they told me i would either pass it as a clot, or the body will absorb. Worse case it could tear my waters.

I passed to massive clots.

Im now 27 week and touch wood no further problems

I had that too (hematoma) in my middle prengnancy (daughter now healthy 6yr old) It was so scary and upsetting at the time. I stupidly Googled it (as you do...) and found lots of horror stories and remember finding out that it is called a threatened miscarriage in America, and they advise complete bedrest. It seems to be where the placenta has detached partly, and as above I was told it would either absorb or come away and that the baby could come away at the same time.
Mine was at about 10 weeks and the blood clot was actually bigger than the baby at the time. I bled for a few weeks off and on and had no idea if the baby was alive until 16 weeks when I paid for a early gender scan, just to check she was ok. The blood was still visible but had reduced by that point.
By the time I had my 20wk scan, the blood had completely disappeared and baby was growing fine.
My other two babies were big 8/ 9lb'ers and my daughter was only 5lb 12oz so she was much smaller than expected. It might have been coincidence, or it could be that the placenta wasn't feeding her as well as part of it was longer attached.
I hope your friend is OK, I remember the stress and worry it caused xx

Thanks both for your replies.
I didn't want to head straight to google as she's not been told any medical names - hence my vague post name!
The fact both of you share your stories so willingly and have happy endings after what I can only imagine were terribly tense pregnancies should put her at ease a little!
Everyone naturally thinks blood and loss, so it's reassuring this isn't always the case.
They've booked her in for 5 'extra' scans, with the next one being in 2 weeks, and then every month (except April which I thought was a bit weird!)
I can research a little further now and know that she's not totally unique!