Early Pregnancy Sac Detection: Understanding Ultrasound Timing

Question
Hi, on an ultrasound when can a sac be seen from actual conception? I had intercourse on October 28th and ultrasound said my conception was October 31st.. from that ultrasound it said i was 10 weeks along.. my first ultrasound before that one up i seen a sac.. the lady said it was to early to tell but she does see something there.. so could i have been 3 weeks or 5 weeks? can you really see a sac at 3 weeks? or is 3 weeks to early to see anything?

Answer
Dear Anna

It is definitely possible to see a 3 weeks gestational sac. However; an importnat point to be aware of, is that doctors calculate the pregnancy age from the first day of your missed period. Considering that ovulation on the average occurs 14 days after the star of menses, you will be pregnant about 2 weeks by the time of your next menses. A doctor would say a 4 weeks pregnancy but the actual age is 2 weeks calculated from the time of ovulation.

I hope these information are helpful.