Cynthia J. Berg

Amniotic fluid embolism (AFE) is a rare but severe complication of pregnancy. A recent systematic review highlighted apparent differences in the incidence, with studies estimating the incidence of AFE to be more than three times higher in North America than Europe. The aim of this study was to examine population-based regional or national data from five high-resource countries in order to investigate incidence, risk factors and outcomes of AFE and to investigate whether any variation identified could be ascribed to methodological differences between the studies.

To estimate the risk of women dying from pregnancy complications in the United States and to examine the risk factors for and changes in the medical causes of these deaths. De-identified copies of death certificates for women who died during or within 1 year of pregnancy and matching birth or fetal death certificates for 1998 through 2005 were received by the Pregnancy Mortality Surveillance System from the 50 states, New York City, and Washington, DC. Causes of death and factors associated with them were identified, and pregnancy-related mortality ratios (pregnancy-related deaths per 100,000 live births) were calculated. The aggregate pregnancy-related mortality ratio for the 8-year period was 14.5 per 100,000 live births, which is higher than any period in the previous 20 years of the Pregnancy Mortality Surveillance System. African-American women continued to have a three- to four-fold higher risk of pregnancy-related death. The proportion of deaths attributable to hemorrhage and hypertensive disorders declined from previous years, whereas the proportion from medical conditions, particularly cardiovascular, increased. Seven causes of death--hemorrhage, thrombotic pulmonary embolism, infection, hypertensive disorders of pregnancy, cardiomyopathy, cardiovascular conditions, and noncardiovascular medical conditions--each contributed 10% to 13% of deaths. The reasons for the reported increase in pregnancy-related mortality are unclear; possible factors include an increase in the risk of women dying, changed coding with the International Classification of Diseases, 10th Revision, and the addition by states of pregnancy checkboxes to the death certificate. State-based maternal death reviews and maternal quality collaboratives have the potential to identify deaths, review the factors associated with them, and take action on the findings.

Postpartum hemorrhage (PPH) is a major cause of maternal mortality and morbidity worldwide. Several recent publications have noted an increasing trend in incidence over time. The international PPH collaboration was convened to explore the observed trends and to set out actions to address the factors identified.

Although the risk of death from complications of pregnancy in the 20th century has decreased dramatically, several lines of evidence suggest that it has not reached an irreducible minimum. To further reduce pregnancy-related mortality, we must understand which deaths are potentially preventable and the changes needed to prevent them. We sought to identify all pregnancy-related deaths in North Carolina and conduct a comprehensive review examining ways in which the number of these deaths could potentially be reduced. The North Carolina Pregnancy-Related Mortality Review Committee reviewed all of the 108 pregnancy-related deaths (women who died during or within 1 year of the end of pregnancy from a complication of pregnancy or its treatment) that occurred in the state in 1995-1999. For each death, the committee determined the cause of death, whether it could have been prevented, and if so, the means by which it might have been prevented. Although overall, 40% of pregnancy-related deaths were potentially preventable, this varied by the cause of death. Almost all deaths due to hemorrhage and complications of chronic diseases were believed to be potentially preventable, whereas none of the deaths due to amniotic fluid embolus, microangiopathic hemolytic syndrome, and cerebrovascular accident were considered preventable. Improved quality of medical care was considered to be the most important factor in preventing these deaths. Among African-American women, 46% of deaths were potentially preventable, compared with 33% of the deaths among white women. Despite the decline in pregnancy-related mortality rates, almost one half of these deaths could potentially be prevented, mainly through improved quality of medical care. In-depth review of pregnancy-related deaths can help determine strategies needed to continue making pregnancy safer.

To describe trends in pregnancy-related mortality and risk factors for pregnancy-related deaths in the United States for the years 1991 through 1997. In collaboration with the American College of Obstetricians and Gynecologists and state health departments, the Pregnancy Mortality Surveillance System, part of the Division of Reproductive Health at the Centers for Disease Control and Prevention, has collected information on all reported pregnancy-related deaths occurring since 1979. Data include those present on death certificates and, when available, matching birth or fetal death certificates. Data are reviewed and coded by clinically experienced epidemiologists. The pregnancy-related mortality ratio was defined as pregnancy-related deaths per 100,000 live births. The reported pregnancy-related mortality ratio increased from 10.3 in 1991 to 12.9 in 1997. An increased risk of pregnancy-related death was found for black women, older women, and women with no prenatal care. The leading causes of death were embolism, hemorrhage, and other medical conditions, although the percent of all pregnancy-related deaths caused by hemorrhage declined from 28% in the early 1980s to 18% in the current study period. The reported pregnancy-related mortality ratio has increased, probably because of improved identification of pregnancy-related deaths. Black women continue to have an almost four-fold increased risk of pregnancy-related death, the greatest disparity among the maternal and child health indicators. Although review of pregnancy-related deaths by states remains an important public health function, such work must be expanded to identify factors that influence the survival of women with serious pregnancy complications.

OBJECTIVE To describe trends in pregnancy-related mortality and risk factors for pregnancy-related deaths in the United States for the years 1991 through 1997. METHODS In collaboration with the American College of Obstetricians and Gynecologists and state health departments, the Pregnancy Mortality Surveillance System, part of the Division of Reproductive Health at the Centers for Disease Control and Prevention, has collected information on all reported pregnancy-related deaths occurring since 1979. Data include those present on death certificates and, when available, matching birth or fetal death certificates. Data are reviewed and coded by clinically experienced epidemiologists. The pregnancy-related mortality ratio was defined as pregnancy-related deaths per 100,000 live births. RESULTS The reported pregnancy-related mortality ratio increased from 10.3 in 1991 to 12.9 in 1997. An increased risk of pregnancy-related death was found for black women, older women, and women with no prenatal care. The leading causes of death were embolism, hemorrhage, and other medical conditions, although the percent of all pregnancy-related deaths caused by hemorrhage declined from 28% in the early 1980s to 18% in the current study period. CONCLUSION The reported pregnancy-related mortality ratio has increased, probably because of improved identification of pregnancy-related deaths. Black women continue to have an almost four-fold increased risk of pregnancy-related death, the greatest disparity among the maternal and child health indicators. Although review of pregnancy-related deaths by states remains an important public health function, such work must be expanded to identify factors that influence the survival of women with serious pregnancy complications.

Objectives: We examined possible reasons for the disparity in the rate of very low birth weight (VLBW) delivery (<1500 g) in the United States between black women and white women. Methods: Using data from a population-based, case–control study of very low birth weight infants, we compared the prevalence of sociodemographic and behavioral characteristics between black and white mothers of normal birth weight infants; the difference in these characteristics between case and control mothers; and, using logistic regression, calculated odds ratios for VLBW for black versus white infants, adjusting for these characteristics. Results: Although black women were disadvantaged on every variable examined, they did not report more behavioral risk factors. Among white women, several traditional risk factors were associated with VLBW, while among black women, only marital status, cigarette smoking, and vitamin nonuse were associated with VLBW delivery. Controlling for the socioeconomic and behavioral factors reduced the odds ratio for VLBW delivery among black mothers from 3.7 to 3.3. Conclusions: Racial disparity in socioeconomic status may be greater than our current ability to adjust for it in epidemiologic studies. The fact that traditional risk factors were not associated with VLBW delivery in black women may be due to the very high prevalence of these risk factors among black women or to different or additional risks or stresses experienced by black women.

Objective: To describe postdelivery mortality rates among residents of Tennessee from 1989 through 1991 and to compare these rates with those of women who had not delivered a live or stillborn infant in the previous year. Methods: Postdelivery deaths (those occurring within a year of delivery of a live or stillborn infant) were identified using a computerized linkage of birth and fetal death certificates to death certificates of female decedents aged 15–44 years. Each identified postdelivery death was reviewed and categorized as either pregnancy-related (temporally and causally related to pregnancy) or pregnancy-associated-but-not-related (temporally but not causally related to pregnancy). Cause-specific mortality rates were compared for women who died postdelivery with women who died but had not delivered in the previous year. Results: We identified 129 postdelivery deaths, one quarter of which were classified as pregnancy-related. The rates of postdelivery pregnancy-related and of pregnancy-associated-but-not-related death were 14.6 and 58.7, respectively, per 100,000 women who had delivered. Nonwhite women were 6.9 times more likely to experience postdelivery pregnancy-related death and 2.0 times more likely to experience postdelivery pregnancy-associated-but-not-related death than were white women. The leading cause of death among both women who had delivered and women who had not delivered a live or stillborn infant in the previous year was injury, although the risk of death the year after delivery was lower than for women who had delivered. Conclusion: Women were less likely to die in the year after delivery than were women who had not delivered a live or stillborn infant in the previous year. However, regardless of their delivery status, injuries were the leading cause of death among women. Postdelivery mortality was statistically significantly higher in nonwhite than white women, especially for pregnancy-related deaths.