As far as I could tell, they could link the hospital admission, OB admission (the hospital runs a separate system for OB) and doctor to the scripts. The RhoGAM

As far as I could tell, they could link the hospital admission, OB admission (the hospital runs a separate system for OB) and doctor to the scripts. The RhoGAM was filled by the hospital pharmacy, and other scripts were filled by CVS. My understanding is that "anonymized" data leaks from subrogration and the PBM as well that can be un-anonymized later.