Dr requested urgent ultra sound

C

So yesterday was my first official appt i got to see baby during my regular appt and since we thought i was further i also had a nuchal ultrasound. The tech let me know i wasn’t measuring where i needed to be to do the testing so i would have to reschedule which was no problem. I rescheduled further out so i would have to deal with not measuring correctly no problem. I ended up receiving a phone call a few hours later saying my dr needs me to get an urgent ultrasound within the next week. What should i think of this? Has this happened to anyone else? What could it be? Baby looked active and heart was beating strong yesterday when we saw him. Why could she want this? Someone help get these thought out of my mind