10 weeks pregnant with only sac visible

I have a friend who is 18 & pregnant. She’s 10 weeks along & had an internal ultrasound at her OB’s. They said everything was fine, but only the sac & i guess part of the umbilical cord were visible. When I was 10 weeks pregnant, I had an external scan & you could see my whole baby. So I am kinda concerned for her. She’s also been bleeding lightly. Has anyone else had this & the pregnancy was fine?