So my OB said at my next appt the ultrasound was just to make sure she sure head down. What would happen if she wasnt??

So my OB said at my next appt the ultrasound was just to make sure she sure head down. What would happen if she wasnt??

ALSO she mentioned theyre gonna do a membrane something to check for Strep B i think. What happens there and what is that strep b thing??