Measuring a week ‘behind’ but no explanation for this?

[EyeCleo]

Hi everyone. I had my follow up ultrasound yesterday. According to my LMP and tracked ovulation, I should be just over 7 weeks. When I had a very early scan two weeks ago, a gestational sac and yolk sac was seen but very small. He increased my progesterone and yesterday returned for follow up. There was now a much larger sac, yolk, and an embryo with CRL measuring 3.7mm. He said this corresponds to 6w1d but this is a discrepancy of a week - but he was reassured that it progressed how he liked in the two weeks since that last scan. He couldn’t detect a heartbeat but said he didn’t want to apply too much pressure to the sac, and I have some adenomyosis that was already putting pressure on it. (Sac was a bit elongated) He said he was happy? And to have another scan in 1-2 weeks to see cardiac activity.

I feel okay… but the discrepancy with my menstrual and ovulation dates is bothering me a lot, and I am worried still. Can anyone enlighten me here what is going on? I’m sure I ovulated around 10th june… and I got first clear positive pregnancy test 23rd June. I just don’t understand how the pregnancy can be only 6 weeks, not 7?

I had an early loss (blighted ovum last year)

Thank you 😢🤍🙏

Being honest with my own experiences not seeing a heartbeat at 7 weeks isn’t great. But unfortunately all you can do is wait and see for the next scan. I’ve had a few missed miscarriages with slow growth and I know how awful they are. Until you know it’s over though there is still hope. I would prepare myself for the worst though if I was you.

Unfortunately I had the same experience, measured a week behind and eventually was what a slow HB ended in a missed miscarriage at almost 8 weeks. Hoping this is a different outcome for you & I have read posts about it going either way.

Hi - I wasn’t 7 weeks though, it was measuring 6 weeks, and no heartbeat. I guess the confusion is as to why the pregnancy is behind :( yep. I hope it’s okay. But of course something isn’t adding up. x

Thanks for sharing. I know, I’m preparing for bad news. I wish I wasn’t. Sorry for your loss x

But I thought you said you were measuring 6 weeks but were actually meant to be over 7 weeks by tracking ovulation? If you are sure of your dates and you should be 7 weeks you should really see a heartbeat by that point regardless of what it is measuring. Sometimes very early on measurements can be a bit out as it’s so small. If you were measuring 6 weeks with a strong heartbeat it might not be as concerning. But if you are sure of your dates and are really meant to be over 7 weeks and there’s no heartbeat that’s why it’s more of an issue. So both measuring behind and no heartbeat in my own experience hasn’t been good news. I had a scan once at 6w6 and was measuring 5w5 with slow heartbeat. 2 weeks later it was still about 6w and no heartbeat. Another time I had a scan at 7w1 and was only measuring 6w and no heartbeat. 2 weeks later was still only 6 weeks so again was a confirmed missed miscarriage.

In many cases women can be wrong with their dates. If you weren’t tracking ovulation it’s possible you ovulated later and that’s why it’s measuring behind. In theory that could still be a possibility. Sometimes the body can try to ovulate but fail so it tries again later. It’s why clinics will never diagnose anything straight away. They will always scan again a week or two later to double check.

When you had your first scan did they tell you what you were measuring then? if it was 2 weeks before the first one and they said you were 6 weeks then you would have only been 4w the first time. Does this add up to what the doctor said B at the first scan?

Hang in there pp. it's a rough ride when you have to wait but sending you best wishes !

Hey yes I see what you mean.
So I was measuring behind at the first one too. Thought I was around 5.5 weeks but sac was very small and there was a yolk sac. He said it seemed more like 4-5 weeks. But couldn’t be sure, just the sac was so small. I got put on progesterone twice daily at this point to help the pregnancy. Went back two weeks later and this is the one measuring approx 6week 1 day the sac had grown considerably, and embryo of 3.7mm but he didn’t want to probe too hard and said the measurements were not fully accurate. So there has been progression but still discrepancy with the dates overall. That’s why it’s confusing because he was very hopeful and optimistic? But, I’m wondering why I’m measuring behind and yes, of course no heartbeat but I know that could still be the case. I asked him about it and he said if he’d pushed harder he probably would have detected it but he didn’t want to press too hard on the sac and it’s being compressed a little by underlying adenomyosis. That’s why he said progesterone would help a lot.

I have my follow up in a week’s time. So that will give me the answer, but yes, I’m very scared it will be another missed miscarriage. I’m trying to find the answer in my head but it’s not appearing. Weird, as I did have a hcg draw repeat at around 5 weeks and it had doubled appropriately. x

Hm if your first was behind too, it sounds like it's all just abit to early!

The progression sounds right.

Hey - thanks so much for reassurance. I wish I could take it BUT I know my dates unfortunately and tracked ovulation with strips and BBT. Even if I got that wrong slightly, the timing of when I got my positive pregnancy test meant I can’t have ovulated much later than I thought, so kind of no explanation as to why I’m measuring a week behind :( a few days at most would be reasonable x