OBJECTIVE: To examine 12 years of anesthesia-related maternal deaths from 1991 to 2002 and compare them with data from 1979 to 1990, to estimate trends in anesthesia-related maternal mortality over time, and to compare the risks of general and regional anesthesia during cesarean delivery.
METHODS: The authors reviewed anesthesia-related maternal deaths that occurred from 1991 to 2002. Type of anesthesia involved, mode of delivery, and cause of death were determined. Pregnancy-related mortality ratios, defined as pregnancy-related deaths due to anesthesia per million live births were calculated. Case fatality rates were estimated by applying a national estimate of the proportion of regional and general anesthetics to the national cesarean delivery rate.
RESULTS: Eighty-six pregnancy-related deaths were associated with complications of anesthesia, or 1.6% of total pregnancy-related deaths. Pregnancy-related mortality ratios for deaths related to anesthesia is 1.2 per million live births for 1991–2002, a decrease of 59% from 1979–1990. Deaths mostly occurred among younger women, but the percentage of deaths among women aged 35–39 years increased substantially. Delivery method could not be determined in 14%, but the remaining 86% were undergoing cesarean delivery. Case-fatality rates for general anesthesia were 16.8 per million in 1991–1996 and 6.5 per million in 1997–2002, and for regional anesthesia were 2.5 and 3.8 per million, respectively. The resulting risk ratio between the two techniques for 1997–2002 was 1.7 (confidence interval 0.6–4.6, P=.2).
CONCLUSION: Anesthetic-related maternal mortality decreased nearly 60% when data from 1979–1990 were compared with data from 1991–2002. Although case-fatality rates for general anesthesia are falling, rates for regional anesthesia are rising.
LEVEL OF EVIDENCE: II