Early pregnancy scan - timings not adding up?

[ForMintGuide]

Hi everyone
this is my first (planned) pregnancy and my partner and I are overwhelmed and lost with what to think! I’ve had endometriosis since i was 17 (now 26) and always been told its not possible. I found out I was pregnant on 30.11.24 and since then have been called in for 3 HCG bloods and an early scan. Blood levels have been rising nicely but at the scan they said it was too early to see anything, and that I was likely 5w+4. My GS was 7.2mm and there was a yolk sac but no visible fetal pole. I went for a follow up scan 5 days later and my GS was 13.5mm, yolk sac and (she thinks?!) a CRL of 1.8mm. This sonographer said I was now at 6w+3. I’m due to have another scan in another week where they’ve said if a heartbeat is not seen, a miscarriage will be called. Can I be 6+3 with a CRL of 1.8 and no heartbeat? Does this all sound ok? It’s extremely overwhelming and we feel like we’re getting mixed messages from everyone. Please help! Thank you

In these situations unfortunately all you can do is wait. Googling will only lead to finding stories that can go either way. I had an early pregnancy scan at what should have been 6.4 and I was only measuring 5.4 but there was a yolk sac and fetal pole. Unfortunately for me 2 weeks later it was the same and it was a missed miscarriage. But those 2 weeks I googled I found plenty of stories that were happy endings. My second one was a scan at 7.2 and there was no heartbeat so we knew instantly that time it was over but I still needed to wait a week to check. Normally I think at 6.3 it’s likely you’d see a heartbeat but not for certain. My IVF clinic prefers to scan after 7 weeks as they feel this is when it is certain you should see one. So next week you will definitely get a conclusive answer.

Hi OP, the diagnosis for unviable pregnancy is not having a heartbeat at 5mm CRL. So you are absolutely fine now at 1.8mm without a heartbeat. The embryo grows 1mm a day so will grow a lot in a week when you will be able to see a heartbeat. The good news is both your sac and embryo are growing nicely (they should both grow about 1mm a day). As for whether the weeks don't match up, at this early stage the ultrasound does have +- 5 days discrepancy as per the NHS guidelines, so don't focus on that. They're pixels at this point so a bit miscalculated here and there adds up to a lot.

I wouldn't worry and enjoy this week. You are pregnant, there is a little baby in there so no cause to worry unless you have to. Easier said than done but there's nothing you can do - so best to assume the best. Good luck!

Also the normal cut off to see a heartbeat before they get concerned is 6w5-7w. So you could have a heartbeat at 6w4d because things change so quickly in there. That's why they wait a week as some embryos grow a bit slower but catch up eventually.

At this early stage dating and even measurements can be very inaccurate as they are literally dealing in fractions of millimetres!
Unfortunately, the only thing that can give you any answers on whether or not this is a viable pregnancy and if everything is OK, is time.
Good luck for your next scan