Ob-Gyn questions? Ask a gynecologist online.
Hello, I'm Dr Manos, M.D., board certified ObGyn. You had an ultrasound on March 6th and were told you had a 6 week sac. That means that conception occurred on February 6th. If you had sex one time from early February 5th to February 9th you could have conceived. I hope this information helps you.