Figure 2. Diagram Indicating Eligible, Excluded, and Analysis Population Beginning With Total Hospital Discharges for New York (NY), California (CA), and Florida (FL) for the Duration of the Observation Period.

Patients younger than age 12 years, missing linkage information, admitted outside of the pregnancy observation time window, and those with false labor, subsequent pregnancies, and nonlabor or delivery admissions were excluded. The exclusion criteria are not mutually exclusive, and patients may fall into more than 1 exclusion category. More than 3 million unique patients with labor and delivery diagnosis were included. Among these patients, those with a prior diagnosis of intracerebral hemorrhage (ICH) were also excluded, resulting in the eligible analysis population for ICH risk. The eligible population was divided into those who did and did not have an ICH diagnosis during pregnancy and the postpartum period. Those who died before the 64-week crossover period and those who were reexposed (pregnant or postpartum period) during the crossover period were excluded from the final matched cohort. Jan indicates January; and Sep, September.