As an aggregate comparison, two of the maternal morbidities in
this report, maternal transfusions and unplanned hysterectomy, are
also included to some extent on the Center for Disease Control and
Prevention’s (CDC’s) list of severe maternal morbidity indicators (32).
These data are collected from a nationally representative survey based
on International Classification of Diseases, Ninth Revision, Clinical
Modification (ICD–9–CM) codes from hospital discharge records in the
United States.