Can I estimate when I conceived?

[Adalanta]

I had a miscarriage on the 28th of March and got pregnant right away, no period in between. I have no idea when I conceived but I had a bit of blood, which proved to be implantation bleeding, on May 2nd. Went to the doctor who confirmed the pregnancy but couldn't see anything on the ultrasound, "it's too small" he said and told me to come back after a week. I' m happy but a bit freaked out, is it normal that he couldn't see anything? Is there a way to find out how many weeks I am?

 

[Topanga053]

When you say there was nothing on the ultrasound, do you mean no baby or really nothing as in no gestational sac? Either way, it's hard to tell if that's cause for concern without knowing your dates. Nothing on the scan can indicate the pregnancy implanted somewhere else (ie ectopic pregnancy), that it's not viable, that your BFP was the result of leftover HCG from your miscarriage, OR that it's simply too early to see anything. Knowing when you think you might have conceived gives you a much better idea which one of these is more likely.

First, are you sure that there is no way the test was positive because of leftover HCG from the miscarriage? Sometimes after a miscarriage it takes a long time for HCG to leave your system (up to months, if there is retained products of conception). For women with leftover HCG, they would still get a positive pregnancy test sometimes weeks later, but it's from the miscarriage and not a new pregnancy. You can rule this out if you've had a negative pregnancy test between your MC and this BFP, if your doctor tested your blood for HCG after the loss, or (in other cases) if you had a period in between. If you didn't get a BFN before you got your positive test, I would suggest there's also a small possibility that its left over HCG and not a new pregnancy, which could also explain nothing showing up on a scan. There would be no way to know if this is the case except to wait. A follow up scan and/or blood draws to determine if your HCG levels are RISING would be the only way to determine whether it's residual HCG or a new pregnancy.

I assume you weren't charting? Do you know the says you DTD? When did you first test positive?

A fertilized egg generally implants 6-10 days after fertilization and a test will usually be positive 3-4 days after that. So, using averages and working backwards, you could have conceived anywhere from about 9-14 days before you first got a positive pregnancy test, assuming this is a new pregnancy (which I hope!!).

Even in healthy pregnancies, it's not surprising to see little to nothing in a scan before 5-6 weeks (or 3-4 weeks after conception). You might see a gestational sac earlier than that, but no baby.

If you tell us when you tested positive, I'm sure we can help you guess how many weeks you might be.

PS- not that it's important, but this is why I don't like really early scans. They're not at all conclusive and they can FREAK US OUT even when the pregnancy is perfectly healthy.

 

[Adalanta]

Thank you so much for taking the time to write such a detailed answer.

I mean there wasn't any sac on the scan. I tested positive on May 4th and I took a blood test on May 5rd, b hcg was 230. When I miscarried it had fallen to 25 a few days later.

You're totally right about early scans, today I have another appointment so I hope we'll get to know what's going on...

 

[lilmisscaviar]

The fact that your levels were at 230 I would estimate you are about 4 weeks pregnant... way too early to see anything on u/s. I would try to wait it out at least 2 more weeks if you hope to see something so you're not worried again. Here is an article about it: https://americanpregnancy.org/while-pregnant/hcg-levels/