I took a pregnancy test the 12th of this month and my LMP was 8/16/12. I tested positive but I got an ultrasound today which I am 4 weeks and 4 days and there was no evidence of a gestational sac. What does this mean?

Was the ultrasound transvaginal or abdominal?

At 4 weeks it may just be too early to see anything. It's best to get retested in a few weeks.

Was the ultrasound transvaginal or abdominal?

At 4 weeks it may just be too early to see anything. It's best to get retested in a few weeks.

It was abdominal - Im an ultrasound student on my extern right now -- there is increased blood flow to the uterus and a thickened endo. I have experienced quite a bit cramping the last few days as well.

At 4 weeks a transvaginal ultrasound is a better choice. Most likely the pregnancy was missed using an abdominal ultrasound.