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Maternal mortality in the United States: predictability and the impact of protocols on fatal postcesarean pulmonary embolism and hypertension-related intracranial hemorrhage

Published:March 17, 2014DOI:https://doi.org/10.1016/j.ajog.2014.03.031

      Objective

      The purpose of this study was to examine the efficacy of specific protocols that have been developed in response to a previous analysis of maternal deaths in a large hospital system. We also analyzed the theoretic impact of an ideal system of maternal triage and transport on maternal deaths and the relative performance of cause of death determination from chart review compared with a review of discharge coding data.

      Study Design

      We conducted a retrospective evaluation of maternal deaths from 2007-2012 after the introduction of disease-specific protocols that were based on 2000-2006 data.

      Results

      Our maternal mortality rate was 6.4 of 100,000 births in just >1.2 million deliveries. A policy of universal use of pneumatic compression devices for all women who underwent cesarean delivery resulted in a decrease in postoperative pulmonary embolism deaths from 7 of 458,097 cesarean births to 1 of 465,880 births (P = .038). A policy that involved automatic and rapid antihypertensive therapy for defined blood pressure thresholds eliminated deaths from in-hospital intracranial hemorrhage and reduced overall deaths from preeclampsia from 15-3 (P = .02.) From 1-3 deaths were related causally to cesarean delivery. Only 7% of deaths were potentially preventable with an ideal system of admission triage and transport. Cause of death analysis with the use of discharge coding data was correct in 52% of cases.

      Conclusion

      Disease-specific protocols are beneficial in the reduction of maternal death because of hypertensive disease and postoperative pulmonary embolism. From 2-6 women die annually in the United States because of cesarean delivery itself. A reduction in deaths from postpartum hemorrhage should be the priority for maternal death prevention efforts in coming years in the United States.

      Key words

      See related editorial, page 1
      Maternal mortality rates in the United States have remained unchanged for several decades, with some data suggesting a recent increase in such deaths.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Berg C.J.
      • Callaghan W.M.
      • Syverson C.
      • Henderson Z.
      Pregnancy-related mortality in the United States, 1998 to 2005.
      • Main E.K.
      • Menard M.K.
      Maternal mortality: time for national action.
      In 2008, we published a review of maternal deaths in approximately 1.5 million births from 2000-2006 and drew a number of conclusions regarding the potential value of several specific steps to address this issue effectively in our system and in the nation as a whole.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      These steps included protocols that were directed at prevention of death from postcesarean pulmonary embolism, intracranial hemorrhage in women with hypertensive crisis, and postpartum hemorrhage.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Clark S.L.
      • Meyers J.A.
      • Frye D.K.
      • Perlin J.B.
      Patient safety in obstetrics: the Hospital Corporation of America experience.
      • Clark S.L.
      Strategies for reducing maternal mortality.
      • Clark S.L.
      • Hankins G.D.V.
      Preventing maternal death: 10 clinical diamonds.
      We present a 6-year observation, detailing clinical results of these efforts. In the current study, we also sought to examine the issue of predictability of maternal death and the potential impact of an ideal system of risk identification and transport on maternal mortality rates. Finally, we examined the correlation between diagnostic accuracy regarding the cause of death that was obtained from coding data, and the data that were obtained from medical records review.
      Because maternal death commonly is defined as deaths per 100,000 live births and may include deaths that are associated with early pregnancy loss or stillbirth, the use of the term maternal mortality ratio to describe these deaths statistically would be correct. However, because the term maternal mortality rate is used almost exclusively throughout the literature to describe maternal deaths during pregnancy, we have observed this convention throughout this article.

      Methods

      The Hospital Corporation of America encompasses 110 maternal/newborn facilities in 21 states. Our annual delivery volume is approximately 210,000 or roughly 5-6% of all births in the United States. Our present study consisted of 3 parts.

      Part 1

      After a review of maternal deaths that occurred in our system from 2000-2006, we developed 3 specific patient safety programs that were aimed at reduction in maternal deaths. (1) All affiliated hospitals instituted the universal use of intra- and postoperative pneumatic compression devices in women who undergo cesarean delivery.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Clark S.L.
      • Meyers J.A.
      • Frye D.K.
      • Perlin J.B.
      Patient safety in obstetrics: the Hospital Corporation of America experience.
      (2) We introduced specific checklist-based protocols that were directed at prompt recognition and treatment of hypertensive crisis, with either labetalol or hydralazine, and emphasized the importance of aggressive recognition and management of preeclampsia-related pulmonary edema (Figure 1, Figure 2).
      • Clark S.L.
      • Meyers J.A.
      • Frye D.K.
      • Perlin J.B.
      Patient safety in obstetrics: the Hospital Corporation of America experience.
      • Clark S.L.
      Strategies for reducing maternal mortality.
      • Clark S.L.
      • Hankins G.D.V.
      Preventing maternal death: 10 clinical diamonds.
      (3) We developed and introduced a checklist-based protocol that is directed at summoning assistance and timely fluid, blood, and component replacement in cases of postpartum hemorrhage (Figure 3).
      • Clark S.L.
      Strategies for reducing maternal mortality.
      Figure thumbnail gr1
      Figure 1Blood pressure management of severe intrapartum or postpartum hypertension with hydralazine
      Checklist.
      IV, intravenously; q, every.
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      Figure thumbnail gr2
      Figure 2Blood pressure management of severe intrapartum or postpartum hypertension with labetalol
      Checklist.
      IV, intravenously; q, every.
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      Figure thumbnail gr3a
      Figure 3Recommended protocol for patients with postpartum hemorrhage
      Checklist.
      CBC, complete blood cell count; EBL, estimated blood loss; NS, normal saline solution; OB, obstetrician; PTT, partial thromboplastin time; RN, registered nurse; SpO2, oxygen saturation; STAT, immediately; T&C, type and crossmatch.
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      Figure thumbnail gr3b
      Figure 3Recommended protocol for patients with postpartum hemorrhage
      Checklist.
      CBC, complete blood cell count; EBL, estimated blood loss; NS, normal saline solution; OB, obstetrician; PTT, partial thromboplastin time; RN, registered nurse; SpO2, oxygen saturation; STAT, immediately; T&C, type and crossmatch.
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      We then conducted a similar review of deaths that occurred between Jan.1, 2007, and Dec. 31, 2012, after the introduction of these protocols. Maternal deaths were identified initially from discharge coding data for the years of interest. Pertinent medical records that pertain to the admission ending in death were then examined for extraction of data used in this analysis. For purposes of determining a causal relationship between cesarean delivery and maternal death, we determined whether delivery of the patient whose death was associated with cesarean delivery would likely have been avoided had the patient been delivered vaginally instead of by cesarean section.

      Part 2

      Causes of death from 2000-2012 were determined from medical record review without regard to coded discharge diagnoses. Then, deidentified discharge diagnostic and procedure codes that were associated with women who died during this period were provided to an author (J.T.C.) who is a maternal-fetal medicine specialist and who, for more than a decade, has served on the Coding Committees of the Society for Maternal Fetal Medicine and the American College of Obstetricians and Gynecologists. This investigator assigned a cause of death that was based exclusively on available discharge diagnostic and procedure codes and was blinded to any medical records. The assignments of cause of death from these 2 different types of reviews were then compared.

      Part 3

      Finally, we examined both cause of death and status on arrival to our facility for each patient in the context of a hypothetical ideal medical system with the following features:
      • There is a specialized high-risk maternal center with full-time maternal-fetal medicine, obstetric anesthesiology, and a medical intensivist available within 30 minutes of the facility of presentation.
      • A preexisting transport agreement exists between the facility of admission and such a center.
      • Transport services are available for all patients without delay.
      • All patients consent to any recommendation for transport.
      • There are no insurance or payment barriers to transport to any area facility.
      We then assigned each patient to one of the following categories, assuming the availability of the system described earlier: (1) The patient had no identifiable risk factors for death when she was admitted that would have prompted transport to such a specialized maternal care center. (2) The patient did have identifiable risk factors that could justify transport to a specialized maternal care center. (3) The patient had known end-stage disease for end-of-life care or already had experienced cardiac arrest before evaluation.
      From these data, we sought to determine the maximum possible effect of an ideal system of maternal transport and availability of specialized referral centers on maternal mortality rates.

      Statistical analysis

      Statistical analysis was performed with the 2-tailed Fisher exact test with a probability value of < .05 cutoff for statistical significance.
      Because this project involved examination of deidentified data for quality improvement purposes, it was exempt from institutional review board approval based on 45CFR46.101(b)
      • Berg C.J.
      • Callaghan W.M.
      • Syverson C.
      • Henderson Z.
      Pregnancy-related mortality in the United States, 1998 to 2005.
      and 46.102(f) and 45CFR164.514(a)-(c) of the Health Insurance Portability and Accountability Act.

      Results

      Between Jan. 1, 2007, and Dec. 31, 2012, there were 81 maternal deaths in 1,256,020 deliveries for a rate of 6.4 per 100,000 births. The mean maternal age at time of death was 30.5 years (range, 17–44 years.) Gestational age distribution at the time of death is outlined in Table 1. For women who delivered in our affiliated institutions, 52% had private insurance; 44% had Medicaid, and 4% were uninsured during the time period of this study.
      Table 1Gestational age at the time of maternal death
      Gestational age, wkDeaths
      0-120
      13-244
      25-3630
      37-4157
      >410
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      Causes of death, as determined from medical records review and a comparison of causes of death from 2007-2012 with those from 2000-2006 are detailed in Table 2. There was a significant decline in the rate of fatal postcesarean pulmonary embolism and a significant decline in the rate of deaths from preeclampsia during the study period, as compared with the earlier control period. During the study period, no hypertensive women died because of untreated in-hospital pulmonary edema or hypertensive crisis, in contrast to our preprotocol experience.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      Two women with severe preeclampsia came to our facilities with intracranial hemorrhage that had occurred before presentation to the hospital. Rates of death from other causes did not change.
      Table 2Cause of death
      Category of death2000-2006 (n = 1,461,270)2007-2012 (n = 1,256,020)P value
      Hemorrhage1119NS .07
      Amniotic fluid embolism1311NS 1.0
      Nonobstetric ID710NS .81
      Other118NS .72
      Postcesarean pulmonary embolism71.038
      Other pulmonary embolism27NS .09
      Cardiovascular108NS .48
      End-stage medical disease15NS .10
      Obstetric ID73NS .36
      Trauma/overdose63NS .52
      Hypertension153.02
      Asthma02NS .21
      Medication error/reaction51NS .23
      Total9581NS 1.0
      ID, infectious disease; NS, not significant.
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      In the entire 12-year cohort of 2,717,290 women, there were 176 maternal deaths. Ninety-nine patients (56%) had no significant risk factors for the ultimate cause of death at the initial examination; 32 women (18%) had known, terminal, or end-stage disease or cardiac arrest. Forty-five patients (26%) had known risk factors on admission for their ultimate cause of death (Table 3). However, 76% of these women were admitted to a specialized center that already met the specialist criteria outlined in the “Methods” section. Thus, only 12 of 176 maternal deaths (7%) would have been preventable potentially with an ideal system of risk identification and transport to universally available specialized centers, even assuming all women with common conditions that included preeclampsia or asthma were transported to specialized centers.
      Table 3Admitting diagnosis of cases amenable to admission triage and transport
      Admitting diagnosisPatients, n
      Hypertensive disease12
      Pneumonia10
      Cardiac disease4
      Placenta accreta4
      Meningitis3
      Thrombotic thrombocytopenic purpura3
      Chronic renal failure2
      Asthma2
      Risk factors for thromboembolism2
      Crack cocaine abuse1
      Transplant rejection1
      Sickle crisis1
      Total45
      Clark. Maternal mortality in the United States. Am J Obstet Gynecol 2014.
      A blinded evaluation of general category of death (Table 2) that was based on diagnosis and procedure coding agreed with the cause of death as determined by chart review in 92 of 176 cases (52%).
      Sixty-eight deaths (84%) were associated with cesarean delivery, and 13 deaths (16%) were associated with vaginal birth (P < .001) However, 30 of the cesarean-associated deaths were perimortem procedures; 35 deaths were related to the indication for cesarean delivery and were unrelated causally to the route of delivery. Only 3 deaths potentially were related causally to cesarean delivery, 1 death each because of surgically induced bleeding, pulmonary hypertension, and a pulmonary embolism after cesarean delivery. Only the first of these could be said to be a definite result of cesarean delivery.

      Comment

      Despite ongoing calls by both professional and lay organizations to address US maternal mortality rates, the rate of death in the United States has remained steady for several decades and appears to be increasing in recent years.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Berg C.J.
      • Callaghan W.M.
      • Syverson C.
      • Henderson Z.
      Pregnancy-related mortality in the United States, 1998 to 2005.
      • Main E.K.
      • Menard M.K.
      Maternal mortality: time for national action.
      • Clark S.L.
      Strategies for reducing maternal mortality.
      • Clark S.L.
      • Hankins G.D.V.
      Preventing maternal death: 10 clinical diamonds.

      Amnesty International. Deadly delivery: the maternal health care crisis in the USA. Available at: http://www.amnestyusa.org/research/reports/deadly-delivery-the-maternal-health-care-crisis-in-the-usa. Accessed Nov. 12, 2013.

      • Wright J.D.
      • Herzog T.J.
      • Shah M.
      • et al.
      Regionalization of care for obstetric hemorrhage and its effect on maternal mortality.
      • Tucker M.J.
      • Berg C.J.
      • Callaghan W.M.
      • et al.
      The black-white disparity in pregnancy-related mortality from 5 conditions: differences in prevalence and case-fatality rates.

      HealthyPeople 2020 Maternal Infant and Child Health. Available at:http://www.healthypeople.gov/2020/topicsobjectives2020/objectiveslist.aspx?topicId=26 Accessed Nov. 12, 2013.

      Although this increase has been attributed, in part, to a change in coding practice in 1999, the rate has continued to climb since that time, which suggests that such deaths are actually increasing in frequency. Healthy People 2020 has set a goal of reducing the US maternal mortality rate to 11.4 in 100,000 live births by 2020.

      HealthyPeople 2020 Maternal Infant and Child Health. Available at:http://www.healthypeople.gov/2020/topicsobjectives2020/objectiveslist.aspx?topicId=26 Accessed Nov. 12, 2013.

      Our rate of 6.4 in 100,000 births is one-half the national average and well below this target, even though we have included in our statistics deaths that would be excluded by World Health Organization definitions because of accidental or incidental causes; elimination of these deaths from our reported population would yield a death rate of 5.6 per 100,000 births The facts that 18% of our patients had known terminal disease for end-of-life care or were transported to our facilities after cardiorespiratory arrest and that a maximum of 7% of women who died in the peripartum period can be identified and potentially out-transported before death suggest that our patient population represents a higher risk subgroup of the general population. From an ethnic, demographic, and geographic standpoint, our population has been shown previously to be representative of the US population as a whole.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Clark S.L.
      • Belfort M.A.
      • Hankins G.D.V.
      • et al.
      Variation in the rates of operative delivery in the United States.
      During this study period, the ethnic makeup of our delivery population was 48% white, 14% black, and 36% Hispanic and other. This closely mirrors the US delivery population for 2008 (52% white, 16% black, and 32% Hispanic and other.)

      Births, Birth rates and fertility. Available at: http://www.census.gov/compendia/statab/2012/tables/12s0081.pdf. Accessed Dec. 2, 2013.

      For this analysis, we also examined insurance availability as an indicator of socioeconomic status. Our delivery population (52% privately insured, 44% Medicaid, and 4% uninsured) corresponds closely with recently published national data from the Centers for Disease Control in which the payment status of women who delivered babies was 57% private insurance and 43% Medicaid.
      • D'Angleo D.V.
      • Williams L.
      • Harrison C.
      • Ahluwalia B.
      Health status and health insurance coverage of women with liveborn infants: an opportunity for preventative services after pregnancy.
      The demographic similarities between the Hospital Corporation of America and the US population as a whole and the fact that our delivery population has a lower percentage of privately insured patients and a higher percentage of patients who are covered by Medicaid supports our belief that the dramatically lower Hospital Corporation of America maternal mortality rate is related primarily to quality of care in our affiliated institutions, rather than population differences.
      Our approach to this and other perinatal quality issues consistently has involved a similar process: (1) identification of possible areas of preventable morbidity or death, (2) collection of data to quantify the nature and extent of the problem, (3) development and promotion of narrowly focused programs that specifically are targeted at problems identified through steps 1 and 2, and (4) remeasurement of quantitative outcome indices to document improvement. As observed by Lord Kelvin, “if you cannot measure it, you cannot improve it.”

      Thompson W (Lord Kelvin). Available at: http://zapatopi.net/kelvin/quotes/. Accessed Nov. 12, 2013.

      This approach has informed all our quality improvement efforts and appears to be more effective than general calls to action and expressions of concern.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Clark S.L.
      • Meyers J.A.
      • Frye D.K.
      • Perlin J.B.
      Patient safety in obstetrics: the Hospital Corporation of America experience.
      • Clark S.L.
      Strategies for reducing maternal mortality.
      • Clark S.L.
      • Hankins G.D.V.
      Preventing maternal death: 10 clinical diamonds.
      • Clark S.L.
      • Belfort M.A.
      • Saade G.A.
      • et al.
      Implementation of a conservative, checklist based protocol for oxytocin administration: maternal and fetal outcomes.
      • Clark S.L.
      • Belfort M.A.
      • Miller D.K.
      • et al.
      Neonatal and maternal outcomes associated with elective term delivery.
      • Mah M.P.
      • Clark S.L.
      • Akhigbe E.
      • et al.
      Reduction of severe hyperbilirubinemia following institution of universal predischarge bilirubin screening in a large private hospital system.
      • Clark S.L.
      • Frye D.R.
      • Meyers J.A.
      • et al.
      Reduction in elective delivery prior to 39 weeks gestation: comparative effectiveness of 3 approaches to change and the impact on neonatal outcome and stillbirth.
      Accordingly, based on data from maternal deaths from 2000-2006, we identified 3 areas of principle focus: postcesarean delivery pulmonary embolism, preeclampsia-related deaths because of uncontrolled hypertension and unrecognized pulmonary edema, and deaths caused by postpartum hemorrhage.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      This recognition gave rise to 3 specific programs.
      First, in 2007, we implemented a program of universal thromboembolism prophylaxis for all women who undergo cesarean delivery. This was followed in 2011 by similar recommendations from the Society for Maternal Fetal Medicine and the American College of Obstetricians and Gynecologists.

      Contemporary OB/GYN. Society for Maternal Fetal Medicine. Thromboprophylaxis for cesarean delivery. June 1, 2011. Available at:http://contemporaryobgyn.modernmedicine.com/contemporary-obgyn/news/modernmedicine/modern-medicine-now/thromboprophylaxis-cesarean-delivery?id=&pageID=1&sk=&date=. Accessed May 5, 2014.

      • James A.
      Committee on Practice Bulletins–Obstetrics. Thromboembolism in pregnancy. American College of Obstetricians and Gynecologists Practice bulletin no. 123.
      Our current data demonstrate a dramatic reduction in deaths from postcesarean thromboembolism after the implementation of this protocol (Table 1). The observed 86% reduction in deaths because of postcesarean pulmonary embolism is in line with reported efficacy of prophylactic measures for other types of major surgery.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      In a similar manner, the development of a highly specific protocol of antihypertensive therapy that is instituted rapidly and automatically without additional physician orders any time that specific blood pressure thresholds are exceeded and an emphasis on prompt recognition and management of preeclampsia–related pulmonary edema resulted in a complete elimination of these causes of death in a delivery population of 1.25 million women and a reduction in the importance of hypertensive disease as a cause of death from #1 to #11 in our population (Figure 1).
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      • Clark S.L.
      Strategies for reducing maternal mortality.
      • Clark S.L.
      • Hankins G.D.V.
      Preventing maternal death: 10 clinical diamonds.
      We are convinced that such very narrowly focused programs that are directed at the specific clinical events within broad categories of disease that actually result in morbidity or death are much more effective than broad programs, bundles, or toolkits that describe the overall management of disease processes. To be most effective, principles of patient safety that are advocated by the Institute of Medicine should inform the development of disease-specific programs, rather than being presented as stand-alone, abstract concepts.
      Institute of Medicine
      Crossing the quality chasm–a new health system for the 21st century.
      Based on our initial data, we also developed a protocol that is aimed at recognition of postpartum hemorrhage, provider notification, and prompt blood and component replacement; actual identification of the cause of hemorrhage and management of such bleeding was left to the discretion of the attending obstetrician.
      • Clark S.L.
      Strategies for reducing maternal mortality.
      In contrast to our success with deaths because of postcesarean pulmonary embolism and hypertension, this program was less effective; we saw no reduction in deaths from hemorrhage in response to this protocol, which suggests that additional efforts will be necessary.
      Although cardiovascular disease remained a leading cause of maternal death, the diversity of pathologic entities within this category (pulmonary hypertension, 2 cases; acute myocardial infarction, 1 case; peripartum cardiomyopathy, 1 case; ruptured splenic, 1 case; aortic aneurism, 1 case; or intracranial aneurism, 2 cases) does not lend itself readily to conclusions regarding preventability, which was a conclusion also reached in our earlier series.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      These data confirm our previous observations regarding the extremely rare causal relationship between cesarean delivery and death.
      • Clark S.L.
      • Belfort M.A.
      • Dildy G.A.
      • et al.
      Maternal death in the 21st century: prevention and relationship to cesarean delivery.
      Only 1 patient's death could be definitively linked in a causal manner, and 3 deaths possibly were linked causally to cesarean delivery of the pregnancy in question in 465,880 such procedures. With 1 million cesarean deliveries performed annually in the United States, our data suggest that 2-6 women die annually in the United States because the delivery was by cesarean section. This is an astounding safety profile and suggests that cesarean delivery is not only the most common major operative procedure in the United States, but also that it is probably the safest.
      In recent years, concern has been expressed regarding the need to establish more definitive criteria for patient transport to specialized centers based on maternal condition and on the development of formal maternal levels of care similar to those in existence for newborn and adult care.
      • Wright J.D.
      • Herzog T.J.
      • Shah M.
      • et al.
      Regionalization of care for obstetric hemorrhage and its effect on maternal mortality.
      • Hankins G.D.
      • Clark S.L.
      • Pacheco L.
      • et al.
      Maternal mortality, near misses, and severe morbidity: lowering rates through designated levels of maternity care.
      • Campbell K.
      • Savitz D.
      • Werner E.F.
      • et al.
      Maternal morbidity and risk of death at delivery hospitalization.
      • Glance L.G.
      • Osler T.M.
      • Mukanel D.W.
      • Dick A.W.
      Impact of trauma center designation on outcomes: is there a difference between level I and level II trauma centers?.
      We found that most women who died during the delivery admission either had no risk factors for the ultimate cause of death on admission (56%) or had known terminal disease or postcardiac arrest (18%). Although 26% of women who died did have known risk factors for death, many of these were very common conditions such as preeclampsia or asthma, which did not appear to pose a significant risk for death at the time of admission. Further, a large proportion of these women were already at an established tertiary care center. Our data should not be interpreted to imply that the establishment of maternal levels of care and the development of specialized regional centers for care of critically ill mothers is not important. Rather, our experience simply suggests that additional factors, which include improved ability to handle emergencies at smaller facilities, will be necessary to materially alter the US maternal mortality rate.
      Two conditions were observed in which frequency was sufficient to warrant special mention. An unusual number of women died of pneumonia in this series.

      HealthyPeople 2020 Maternal Infant and Child Health. Available at:http://www.healthypeople.gov/2020/topicsobjectives2020/objectiveslist.aspx?topicId=26 Accessed Nov. 12, 2013.

      Several of these cases involved the recent H1N1 pandemic during which pregnant women were observed to be especially vulnerable to death. In addition, 3 women died of complications of placenta accreta, despite preoperative knowledge of this condition and delivery in large, metropolitan tertiary care centers. These data would suggest that pregnant women with any form of pneumonia may be at heightened risk of death and should be cared for in a regional center. Further, we emphasize the fact that placenta accreta may be a lethal condition, despite optimal care; such women must be delivered in large centers with ready access to both multiple surgical specialists and massive blood banking capability. These observations also support the concept that women with suspected placenta accreta may benefit from the establishment of quarternary regional care centers that focus on the management of this condition and have resources beyond those available at many tertiary centers. That such transfer is essential for women with many of the other high-risk conditions that were identified in this series is self-evident (Table 3).
      When blinded to any medical record information, a review of discharge diagnosis and procedure codes resulted in a correct identification of cause of death in only 52% of cases. Such inaccuracies reflect the complex nature of many of the conditions that lead to maternal death. This type of side-by-side comparison has not been published previously and suggests the need for great caution in the interpretation of published data that involve maternal morbidity and death based on administrative data, rather than on medical record review. Certainly, any serious review of maternal death at the institutional or governmental level must involve chart review by experienced and knowledgeable physician specialists if the purpose of review is quality improvement.
      Despite the success of protocols directed at deaths from preeclampsia and postcesarean pulmonary embolism, several problematic areas remain. First, our overall mortality rate did not decline significantly. We attribute this primarily to increased disease acuity. Six women were admitted to our affiliated hospitals with known terminal illness for end-of-life care and delivery compared with 1 from 2000-2006, and 12 women were admitted to our facilities after out-of-hospital cardiac arrest compared with 3 from 2000-2006. If one considers only the care of nonterminal, potentially salvageable patients, we experienced a 19% decline in maternal deaths from 2007-2012. This observation raises the possibility that the recent upward trends in national death rates that was discussed earlier may also be influenced by similar increased acuity in the US population as a whole.
      Although deaths from postcesarean pulmonary embolism were reduced dramatically with perioperative prophylaxis, we continued to see a significant number of deaths from antepartum thrombosis and after vaginal delivery in women who would not currently be candidates for any form of thromboembolism prophylaxis. This finding speaks to the need for additional studies to be directed at the identification of women at particular risk for venous thromboembolism in addition to the classic postoperative group.

      Royal College of Obstetricians and Gynecologists. Reducing the risk of thrombosis and embolism during pregnancy and the puerperium. Available at: http://www.rcog.org.uk/files/rcog-corp/GTG37aReducingRiskThrombosis.pdf. Accessed May 1, 2014.

      Finally, despite implementation of protocols that facilitate both prompt provider notification and blood and component replacement, deaths from hemorrhage did not decrease. Our analysis of case detail suggests that life-threatening postpartum hemorrhage may simply be too uncommon to afford adequate training to many otherwise well-trained obstetricians and nurses; when faced with an actual patient rapidly bleeding to death, a knowledge of general principles of treatment and experience with less critical patients may not be sufficient. We are in the process of developing a step-by-step protocol for recognition and management of uterine atony, retained placenta, lacerations, and coagulopathy, which is as specific and prescriptive as those that have proved so effective in the management of hypertensive crisis (Figure 1).
      • Clark S.L.
      Strategies for reducing maternal mortality.
      Our data suggest that the management of postpartum hemorrhage remains the last major potentially preventable category of death in the United States without a good solution.
      • Dilla A.J.
      • Waters J.H.
      • Yazer M.H.
      Clinical validation of risk stratification criteria for peripartum hemorrhage.
      Management of postpartum hemorrhage should be the major focus of future efforts to reduce the maternal mortality rate in this country.

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