An uncomplicated in-hospital birth (I10_UNCBRTH = 1) is defined as an in-hospital birth for which the Medicare MS-DRG equaled 796 "Normal Newborn" (DRG 391 prior to 2009). In-hospital births (I10_HOSPBRTH = 1) are defined by two conditions:

• A principal or secondary diagnosis code indicating a live birth (Z38.00, Z38.01, Z38.2, Z38.30, Z38.31, Z38.5, Z38.61-Z38.69, Z38.8) and
• The patient is not born outside the hospital (PointOfOriginUB04 not equal 6 when ATYPE is equal to 4) and not transferred from another acute care hospital or health care facility (PointOfOriginUB04 is not equal to 4, 6, B, D, E, or F, when ATYPE is not equal to 4 or missing; or ASOURCE is not equal 2 or 3).

For data prior to the fourth quarter of 2015, the uncomplicated in-hospital birth indicator is stored in the data element UNCBRTH to indicate the use of the ICD-9-CM coding system.