Everything went okay down hospital yesterday, was put on monitor and she liked how babies heartbeat…

Everything went okay down hospital yesterday, was put on monitor and she liked how babies heartbeat was and the movements, kept losing his heartbeat but he's fine, just hiding away from us all😦 booked in now for a scan on Tuesday so I'm hoping he's growing okay and everything is fine, if they are happy with heartbeat why do the doctors book you in for a scan?