No heartbeat?

They are so small at that point and may not be where expected so I understand it's not uncommon to not hear the heartbeat yet.  If it's any solace, they had a hard time finding my son's heartbeat at different times througout my pregnancy--even at 39 weeks and the day of my c-section.  He moved even then and was not where he should have been and was not in the position he should have been in.  If you do get concerned, don't hesitate to call and request an ultrasound--they'd rather do another one that have you worry.