I just got back from the E.R. where I had a Threatened Miscarriage (thankfully baby seems to still be alive!). This is my 7th pregnancy with 5 alive children. I am 100% certain of my conception date (March 13th) which would make me 9wks and 3days along, however at the E.R. I was only measuring 5 1/2 weeks. No heartbeat was detected (too early I was told), and my HcG levels were 6066 which does place me 5-6 weeks, however, I am POSITIVE of my conception date. Any other possibilities of why I could be measuring small? Thanks.