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Pregnancy: Ages 25-34 Community
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Avatar universal

Early ultrasound vs last menstrual period, which is more accurate?

I thought I had a period that started Jan 25 and lasted around 5-6 days, it was a little lighter than normal, but it lasted long enough that I was sure it was a period. My periods have always been regular and its never more than 28 days in my cycle. My previous period started Dec 29, so it seemed about the right time for me to have a period. In March I missed my period and took an at home pregnancy test because I was a few days late, it read positive in 5 seconds. I went to the doctor to see how far along I was because I was using the Nuvaring for birth control. I never took it out until it had been there for 3 weeks, so I was shocked that I was pregnant. At that time the doctor told me I was at least 8 weeks, which means what I thought was a period in January was implantation bleeding. If I go by my last menstrual period it started on December 29, which would put me at 13w2d. According to the date the doctor gave me based on my vaginal ultrasound, I am 12w on Wed. Which is more accurate? The early ultrasound measured my embryo to be 17.8mm at 8 weeks according to the doctor, does anybody else have measurements of their embryo at 8 weeks? Just curious:-)
5 Responses
Avatar universal
The transvaginal ultrasound is more accurate at that stage all babies develope the same.
Avatar universal
Ultrasound is much more accurate than last period.
Avatar universal
Since it's pretty much impossible to calculate the exact moment of conception they use the ultrasound to take measurements. This is the most accurate. Congrats!
Avatar universal
My last menstrual was jan 25 and im 9 weeks. Your pregnancy starts from the first day of your last period (it includes your period week) so the 8 week measurement is right. So in January that was your period as you suspected.
Avatar universal
Thank all of you that responded to my post!
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