IVF transfer then hcg then no hcg then hcg

someone help...........
I had a frozen embryo (well graded) transfer on may 7...on may 11 my hcg was 9...then may 13  and may 14 my hcg level was less than 1 confirmed by 2 different labs...so no lab error...then on may 18 my hcg was 44....how the heck did this happen...did i get pregnant on my own...remember w a transfer we dont take meds that show hcg in blood....anyone have an explanation

[Stacey1718]

Very confusing.  May 11 would have been really early to get a positive but you never know. The most important thing is that your May 18 number is great!  That is definitely a positive!  Your numbers should double at your next blood test.

Congratulations!!  

[40smama]

Could there still be hcg leftover from the trigger that caused the first BFP - especially since it was done 4 days after transfer?

It seems to me that would explain it - that there was still hcg in your system from the trigger, then once it was out, you got the BFN and then now you're pregnant and the embryo's producing HCG.  Just a theroy anyway

Congrats on your BFP & SSBD! - jen