Fetal pole but no heartbeat? (6 weeks pregnant)

Hi, all. I just went in for an early scan (6 weeks 1 day) and the doctor told me that I should likely prepare to miscarry, as they detected a fetal pole, but no heartbeat. Fetal pole measured 4 mm. She made it seem like there should always be a heartbeat if a fetal pole is present. I just miscarried 3 months ago as well, so I’m heartbroken that she thinks this will be the outcome. Just wondering if anybody has had a similar experience. Any insight is greatly appreciated.

Update for anybody that comes across this thread in the future:

I went back 6 days later and baby had a strong heartbeat and was measuring right on track at a little over 7 mm!!! I was just a little too early the first time.