TABLE.

Sources of Maternal Mortality Information in the United States

	NATIONAL CENTER FOR HEALTH STATISTICS (NCHS)	PREGNANCY MORTALITY SURVEILLANCE SYSTEM (PMSS)
Data source	Death certificates	Death certificates linked to fetal death and birth certificates
Time frame	During pregnancy to 42 days postpartum	During pregnancy to 365 days postpartum
Source of classification	ICD-10 codes	Medical epidemiologists assign PMSS codes
Terms	Maternal death	Pregnancy-associated death
		Pregnancy-related death
		Associated but not pregnancy-related death
Measure	Maternal Mortality Rate	Pregnancy-Related Mortality Ratio
	= # of maternal deaths per 100,000 live births	= # of pregnancy-related deaths per 100,000 live births
Purpose(s)	Show national trends and provide basis for international comparison	Analyze clinical factors associated with deaths, publish information that may lead to prevention strategies
Strengths	Best source of historical data (back to 1900)	Most clinically relevant national measure of the burden of maternal deaths
	Reliable basis for international comparison
	Based on readily available data (death certificates)
Challenges	Constrained by ICD-10 codes	Constrained by information available on death and birth certificates
	Lacks sufficient detail to inform prevention strategies	Lacks detailed information on contributors to death

ICD-10=International Classification of Diseases, 10th Revision.

Adapted from St Pierre et al. (80)