I had INVitro Fertilization done, and gave birth to twin boys. The invitro was very calculated. I had a positive pregnancy test 10 days after they transfered my eggs back inside of me. The embryos were 5days old when they put them back, and in 10days my urine & blood tested positive. That would make them 15days old, and they were secreting hcg. also my hcg blood levels were so high on the 10th day, they knew I was having twins. The embryo secretes the hcg hormone instantly, I am sure, even before implantation, it just goes undectected until the embryo grows. They are also able to tell if the embryo is healthy by the hcg levels. If you #'s double everyother day, that is a good sign. I had an ectopic as well, and the hcg levels grew but did not double, and they knew by the 1st two blood draws that the pregnancy would not make it.
HI IT IS PROBABLY AFTER IMPLANTANTION.IT TAKES ABOUT 1 OR 2 MONTHS FOR THE HCG HORMONE TO SHOW UP IN YOUR BLOOD OR URINE.THE ONLY WAY TO FIND OUT IS TO HAVE PREGNANCY TEST.IF YOU HAVE MISSED ONE,AND USUALLY DON'T MISS A PERIOD,YOU MIGHT BE.YOU HAVE TWO OPTIONS BUY A HOME PREGNANCY TEST OR MAKE AN APPOINTMENT WITH YOUR GYNECOLOGIST.GOOD LUCK.TAKE CARE OF YOUR SELF TNT406.