Important Question!

T
I feel silly asking this, but here goes. Having a brain freeze. 
Last month I went to a fertility specialist in the same office as my obgyn. So he advised on some supplements but strongly encouraged  assisted fertility treatment and iui due to my low AMH. This month after taking supplements I found out I am pregnant. So my question is this: do I go to fertility specialist to check my beta blood work or go straight to my obgyn? Fertility doctor just ran some blood work tests and saline sonogram. 
What do you ladies think?