Pregnancy dating on ultrasound

danieller426

I had an early pregnancy ultrasound today which (based on the GS and yolk sac) measured me at 5 weeks and 2 days pregnant. I had a scan on the Thursday prior which didn’t show a GS yet, so I know there is growth since then. I am worried however, because I have a history of miscarriages and pregnancies not progressing appropriately. I had a miscarriage at the end of July and never got my period. I have only had sex once in the month of October (on Oct 9), and based on the date on my ultrasound it determines conception date to be on Oct 17. Is it possible to conceive a full week after having sex? And, does anyone have experience with the dating of very early pregnancy scans being off at this stage? I’m not sure if I should be worried or not. I also started prednisone to suppress my immune system as soon as I found out I’m pregnant, as prescribed by a reproductive immunologist, who believe my immune system has attacked previous pregnancies.

holly321

danieller426 said:

I had an early pregnancy ultrasound today which (based on the GS and yolk sac) measured me at 5 weeks and 2 days pregnant. I had a scan on the Thursday prior which didn’t show a GS yet, so I know there is growth since then. I am worried however, because I have a history of miscarriages and pregnancies not progressing appropriately. I had a miscarriage at the end of July and never got my period. I have only had sex once in the month of October (on Oct 9), and based on the date on my ultrasound it determines conception date to be on Oct 17. Is it possible to conceive a full week after having sex? And, does anyone have experience with the dating of very early pregnancy scans being off at this stage? I’m not sure if I should be worried or not. I also started prednisone to suppress my immune system as soon as I found out I’m pregnant, as prescribed by a reproductive immunologist, who believe my immune system has attacked previous pregnancies.

I am sorry for your lmprevious loss and anxiety from your scan.  I have had more than my fair share of losses, and honestly,  in my experiences early ultrasound had been no indicator of how the pregnancy will progress.

Early ultrasounds can be off by a few days, which can make a huge difference in growth that early.
With my  oldest son, I know when I ovulated and went for an ultrasound and should have been around 7 weeks.  Scan showed 6 weeks and what seemed an inconsistent HB, around a week later, I was measuring 8 weeks.   I think you can get pregnant from sex that occurs 4-5 days before ovulation  

capnjackharkness

@danieller426 Unfortunately for me, the ultrasounds dating slowly has never boded well in my situations.  However, many people see early ultrasounds that can be off a bit and/or pregnancies that seem to progress a bit slower at the beginning and are fine.  I'm sorry for your losses, I know how stressful these earlier stages are if you have a history of earlier losses.  What does your RE/OB say?  If you haven't had testing and are working with a specialist who knows about your history of losses, I would definitely recommend it at this point to help monitor you more closely and be able to walk you through the specifics of your case while you're in the early stages of pregnancy.

danieller426

So I went back today, and they narrowed the gap by 1 day. So now I’m measuring 6 weeks exactly, with a low normal FHR of 90. On Monday I was measuring at 5w2d, which made me nervous because (although I’m not exactly sure what day I ovulated) that put my conception date at exactly a week after I had sex. So I don’t know if there is an issue yet, or it was just a late ovulation and late implantation. Hopefully the FHR goes up at the next sonogram, otherwise I will know there’s an issue.