Cynthia J. Berg

Pregnancy-Related Mortality in the United States, 1991-1997

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.

Pregnancy-Related Mortality in the United States, 1998 to 2005

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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, 10thRevision, 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. LEVEL OF EVIDENCE: III

Trends in postpartum hemorrhage in high resource countries: a review and recommendations from the International Postpartum Hemorrhage Collaborative Group

AbstractBackgroundPostpartum 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.MethodsWe reviewed available data sources on the incidence of PPH over time in Australia, Belgium, Canada, France, the United Kingdom and the USA. Where information was available, the incidence of PPH was stratified by cause.ResultsWe observed an increasing trend in PPH, using heterogeneous definitions, in Australia, Canada, the UK and the USA. The observed increase in PPH in Australia, Canada and the USA was limited solely to immediate/atonic PPH. We noted increasing rates of severe adverse outcomes due to hemorrhage in Australia, Canada, the UK and the USA.ConclusionKey Recommendations 1. Future revisions of the International Classification of Diseases should include separate codes for atonic PPH and PPH immediately following childbirth that is due to other causes. Also, additional codes are required for placenta accreta/percreta/increta.2. Definitions of PPH should be unified; further research is required to investigate how definitions are applied in practice to the coding of data.3. Additional improvement in the collection of data concerning PPH is required, specifically including a measure of severity.4. Further research is required to determine whether an increased rate of reported PPH is also observed in other countries, and to further investigate potential risk factors including increased duration of labor, obesity and changes in second and third stage management practice.5. Training should be provided to all staff involved in maternity care concerning assessment of blood loss and the monitoring of women after childbirth. This is key to reducing the severity of PPH and preventing any adverse outcomes.6. Clinicians should be more vigilant given the possibility that the frequency and severity of PPH has in fact increased. This applies particularly to small hospitals with relatively few deliveries where management protocols may not be defined adequately and drugs or equipment may not be on hand to deal with unexpected severe PPH.

Risk factors for legal induced abortion-related mortality in the United States.

OBJECTIVE: To assess risk factors for legal induced abortion–related deaths. METHODS: This is a descriptive epidemiologic study of women dying of complications of induced abortions. Numerator data are from the Abortion Mortality Surveillance System. Denominator data are from the Abortion Surveillance System, which monitors the number and characteristics of women who have legal induced abortions in the United States. Risk factors examined include age of the woman, gestational length of pregnancy at the time of termination, race, and procedure. Main outcome measures include crude, adjusted, and risk factor–specific mortality rates. RESULTS: During 1988–1997, the overall death rate for women obtaining legally induced abortions was 0.7 per 100,000 legal induced abortions. The risk of death increased exponentially by 38% for each additional week of gestation. Compared with women whose abortions were performed at or before 8 weeks of gestation, women whose abortions were performed in the second trimester were significantly more likely to die of abortion-related causes. The relative risk (unadjusted) of abortion-related mortality was 14.7 at 13–15 weeks of gestation (95% confidence interval [CI] 6.2, 34.7), 29.5 at 16–20 weeks (95% CI 12.9, 67.4), and 76.6 at or after 21 weeks (95% CI 32.5, 180.8). Up to 87% of deaths in women who chose to terminate their pregnancies after 8 weeks of gestation may have been avoidable if these women had accessed abortion services before 8 weeks of gestation. CONCLUSION: Although primary prevention of unintended pregnancy is optimal, among women who choose to terminate their pregnancies, increased access to surgical and nonsurgical abortion services may increase the proportion of abortions performed at lower-risk, early gestational ages and help further decrease deaths. LEVEL OF EVIDENCE: II-2

Trends in postpartum hemorrhage: United States, 1994–2006

OBJECTIVE The purpose of this study was to estimate the incidence of postpartum hemorrhage (PPH) in the United States and to assess trends. STUDY DESIGN Population-based data from the 1994-2006 National Inpatient Sample were used to identify women who were hospitalized with postpartum hemorrhage. Data for each year were plotted, and trends were assessed. Multivariable logistic regression was used in an attempt to explain the difference in PPH incidence between 1994 and 2006. RESULTS PPH increased 26% between 1994 and 2006 from 2.3% (n = 85,954) to 2.9% (n = 124,708; P < .001). The increase primarily was due to an increase in uterine atony, from 1.6% (n = 58,597) to 2.4% (n = 99,904; P < .001). The increase in PPH could not be explained by changes in rates of cesarean delivery, vaginal birth after cesarean delivery, maternal age, multiple birth, hypertension, or diabetes mellitus. CONCLUSION Population-based surveillance data signal an apparent increase in PPH caused by uterine atony. More nuanced clinical data are needed to understand the factors that are associated with this trend.

Preventability of pregnancy-related deaths: results of a state-wide review.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. LEVEL OF EVIDENCE: III

Association between Obesity during Pregnancy and Increased Use of Health Care

BACKGROUND In the United States, obesity during pregnancy is common and increases obstetrical risks. An estimate of the increase in use of health care services associated with obesity during pregnancy is needed. METHODS We used electronic data systems of a large U.S. group-practice health maintenance organization to identify 13,442 pregnancies among women 18 years of age or older at the time of conception that resulted in live births or stillbirths. The study period was between January 1, 2000, and December 31, 2004. We assessed associations between measures of use of health care services and body-mass index (BMI, defined as the weight in kilograms divided by the square of the height in meters) before pregnancy or in early pregnancy. The women were categorized as underweight (BMI <18.5), normal (BMI 18.5 to 24.9), overweight (BMI 25.0 to 29.9), obese (BMI 30.0 to 34.9), very obese (BMI 35.0 to 39.9), or extremely obese (BMI > or =40.0). The primary outcome was the mean length of hospital stay for delivery. RESULTS After adjustment for age, race or ethnic group, level of education, and parity, the mean (+/-SE) length of hospital stay for delivery was significantly (P<0.05) greater among women who were overweight (3.7+/-0.1 days), obese (4.0+/-0.1 days), very obese (4.1+/-0.1 days), and extremely obese (4.4+/-0.1 days) than among women with normal BMI (3.6+/-0.1 days). A higher-than-normal BMI was associated with significantly more prenatal fetal tests, obstetrical ultrasonographic examinations, medications dispensed from the outpatient pharmacy, telephone calls to the department of obstetrics and gynecology, and prenatal visits with physicians. A higher-than-normal BMI was also associated with significantly fewer prenatal visits with nurse practitioners and physician assistants. Most of the increase in length of stay associated with higher BMI was related to increased rates of cesarean delivery and obesity-related high-risk conditions. CONCLUSIONS Obesity during pregnancy is associated with increased use of health care services.

Identification of severe maternal morbidity during delivery hospitalizations, United States, 1991-2003.

OBJECTIVE This investigation aimed to identify pregnancy complications and risk factors for women who experienced severe maternal morbidity during the delivery hospitalization and to estimate severe maternal morbidity rates. STUDY DESIGN We used the National Hospital Discharge Survey for 1991-2003 to identify delivery hospitalizations with maternal diagnoses and procedures that indicated a potentially life-threatening diagnosis or life-saving procedure. RESULTS For 1991-2003, the severe maternal morbidity rate in the United States was 5.1 per 1000 deliveries. Most women who were classified as having severe morbidity had an ICD-9-CM code for transfusion, hysterectomy, or eclampsia. Severe morbidity was more common at the extremes of reproductive age and for black women, compared with white women. CONCLUSION Severe maternal morbidity is 50 times more common than maternal death. Understanding these experiences of these women potentially could modify the delivery of care in healthcare institutions and influence maternal health policy at the state and national level.

Barriers and motivators to prenatal care among low-income women

Substantial evidence exists which links prenatal care to improved birth outcomes. However, low-income and nonwhite women in the United States, who are at greatest risk for poor birth outcomes, continue to receive the poorest prenatal care. The purpose of this study was to identify and compare barriers and motivators to prenatal care among women who lived in low-income census tracts. The stratified sample included recently delivered white, black and American Indian women who received adequate, intermediate, and inadequate prenatal care. Interviews were conducted which focused primarily on the womens perceptions of problems in obtaining prenatal care and getting to appointments. Results indicated that women with inadequate care identified a greater number of barriers and perceived them as more severe. Psychosocial, structural, and socio-demographic factors were the major barriers, while the mothers beliefs and support from others were important motivators. The predictive power of selected barrier variables was examined by a regression analysis. These variables accounted for 50% of the variance in prenatal care use. The results affirm the complexity of prenatal care participation behavior among low-income women and the dominant influence of psychosocial factors. Comprehensive, coordinated and multidisciplinary outreach and services which address psychosocial and structural barriers are needed to improve prenatal care for low-income women.

Maternal mortality in developed countries: Not just a concern of the past**

Objective To review the activities in selected developed countries for strategies to identify maternal deaths, the impact of these strategies on underreporting, and the information needed to understand the events leading to death. Data Sources We reviewed the literature from the United States, Europe, and Australia for publications dealing with maternal death identification and investigation from 1980 to April 1995. We also obtained information directly from researchers involved in major maternal mortality studies. Methods of Study Selection We included all 31 reports (from 14 countries) that discussed methods to improve the ascertainment of maternal deaths beyond the routine use of vital registration. Because of the nature of the subject matter, almost all reports relied on descriptive epidemiology. Data Extraction and Synthesis We found that a variety of methods can be used to improve the ascertainment of maternal deaths, including linkage of birth and fetal death certificates, check-boxes on death certificates, periodic review of deaths of reproductive-age women, and ongoing birth registries and medical audits. Information from a variety of sources is also needed to understand the events leading to death. Conclusion The numbers of deaths due to pregnancy and its complications are underestimated in most developed countries. Improved ascertainment of maternal death is needed to determine the magnitude of the problem and to assess trends and identify risk groups, allowing development of appropriate and effective strategies to prevent the morbidity and mortality associated with pregnancy.