Assessing the relationship between census tract rurality and severe maternal morbidity in California (1997-2018)

Area of Science:

• Reproductive Health
• Health Services Research
• Rural Health Disparities

Background:

• Existing research indicates elevated severe maternal morbidity (SMM) risks for individuals in rural counties compared to urban ones.
• Previous studies have not explored rurality at the granular subcounty census-tract level, limiting a nuanced understanding of geographic disparities.

Purpose of the Study:

• To investigate the association between subcounty-level rurality and the risk of severe maternal morbidity (SMM) among birthing individuals in California.
• To determine if a more detailed, census-tract level analysis of rurality reveals different patterns of SMM risk compared to broader county-level assessments.

Main Methods:

• Utilized linked vital statistics and hospital discharge records for births in California from 1997 to 2018.
• Defined SMM using 21 potentially fatal conditions and lifesaving procedures.
• Characterized census tract rurality using Rural-Urban Commuting Area codes (2- and 4-category classifications) and employed mixed-effects logistic regression models.

Main Results:

• Out of 10,091,415 births, 1.1% experienced SMM.
• A 10% higher risk of SMM was observed for individuals in rural versus urban tracts (2-category model).
• A 16% higher risk of SMM was found in micropolitan versus metropolitan tracts (4-category model), indicating a significant association at the subcounty level.

Conclusions:

• The elevated risk of SMM associated with rurality is primarily driven by residence in micropolitan census tracts compared to metropolitan ones.
• Potential inequities in resource access within suburban areas may contribute to the observed disparities.
• Emphasizes the critical importance of analyzing rurality at the subcounty census-tract level to accurately identify and address geographic variations in SMM risk.