Maternal death analysis based on data from the nationwide registration system in Japan (2010-2018).

The maternal mortality rate in Japan was 3.5 per 100 000 live births in 2017, similar to that reported in other developed countries. To reduce the number of maternal deaths, a Japanese nationwide registration and analysis system was implemented in 2010. Between January 2010 and April 2018, 367 maternal deaths were reported. Among them, by reviewing 80 autopsy records, the direct obstetric causes of death were identified in 52 women. The major causes of deaths were amniotic fluid embolism and acute pulmonary thromboembolism. The other 26 maternal deaths were associated with indirect obstetric causes including invasive Group A Streptococcus infection, aortic dissection, cerebral stroke and cardiomyopathies. This review highlights the importance of autopsy in maternal deaths. On analyzing 42 autopsy specimens obtained from registered cases of maternal death during 2012-2015, the 36% of causes of death by autopsy were discordant with the clinical diagnosis. Moreover, of the 38% of non-autopsied maternal death, the cause of death could not be clarified from the clinical chart. We emphasized that detailed autopsies are necessary to clarify the precise pathologic evidence related to pregnancy and delivery, especially causes of unexpected death such as amniotic fluid embolism.

Evaluation of the 4 diagnosis criteria proposed by the SMFM and the AFE foundation for amniotic fluid embolism in a monocentric population.

OBJECTIVE: The Society of Maternal Fetal Medicine (SMFM) and the Amniotic Fluid Embolism Foundation have recently proposed four diagnostic criteria for amniotic fluid embolism (AFE): presence of (1) sudden cardiac arrest or both respiratory and hemodynamic collapse, and (2) biological disseminated intravascular coagulopathy (DIC), and (3) absence of fever, and (4) clinical onset during labor or within 30 min of delivery. The objectives of our study were to describe the clinical presentation of women with a strong suspicion of AFE and to assess the validity of the four criteria proposed for AFE definition. MATERIAL AND METHODS: We performed a retrospective study including all patients with a strong suspicion of AFE who delivered between 2006 and 2018 at the Port Royal maternity unit, Paris. Strong suspicion of AFE was defined by a clinical presentation in favor of AFE associated with a biological pattern and/or autopsy result supporting AFE. The mention of AFE in files was essential to include the patients in our study. We estimated the incidence and mortality rate of AFE. Then, the presence of each of the four diagnosis criteria of the SMFM score was described, as well as the clinical and biological patterns. RESULTS: Among the 54 140 women who delivered during the study period, 14 had a strong suspicion of AFE (0.03 %), accounting for 25.9/100 000 deliveries (95 %CI (12.3-39.5/100,000)). All women had biological tests or autopsy supporting the diagnosis of AFE. Six of 14 patients (43 %) presented with all the four diagnostic criteria of the SMFM definition. All 14 women presented a hemodynamic collapse, but respiratory symptoms were lacking in 8 patients (57 %); 71 % fulfilled the criterion of biological DIC, and all patients had a clinical coagulopathy and a massive postpartum hemorrhage. Absence of fever was lacking in three women. In addition, all patients presented premonitory symptoms such as neurological disorders or irreversible and inaugural fetal bradycardia. CONCLUSION: The four SMFM diagnostic criteria were present in less than half of the women with a strong suspicion of AFE. We propose an alternative clinical and pragmatic definition to diagnose AFE, which has to be validated in the future. Early diagnosis of AFE based solely on clinical criteria can help clinicians anticipate the severity of the situation and optimize care.

Anesthetic management of amniotic fluid embolism -- a multi-center, retrospective, cohort study.

INTRODUCTION: Amniotic fluid embolism (AFE) is a rare and potentially lethal obstetric complication, commonly occurring during labor, delivery, or immediately postpartum. There is a paucity of data regarding incidence, risk factors, and clinical management. Our primary objective in this study was to evaluate clinical presentation of AFE and delineate anesthesia management of these cases. METHODS: This 10 years retrospective multi-center cohort study was performed in five tertiary university-affiliated medical centers, between the years 2005 and 2015. All documented cases of AFE identified according to the ICD guidelines were reviewed manually to determine eligibility for AFE according to Clark's criteria. All cases confirming Clark's diagnosis were included in the cohort. RESULTS: Throughout the study period, 20 cases of AFE were identified, with an incidence of 4.1 per 100,000 births. Average age at presentation was 35 ± 5 years. Seventy percent of cases presented during vaginal delivery, 20% occurred throughout a cesarean delivery, and 10% occurred during a dilation and evacuation procedure. The most common presenting symptom was sudden loss of consciousness in 12 parturients (66.7%), fetal bradycardia in 11 parturients (55%), and shortness of breath in 10 parturients (50%). Perimortem cesarean section was performed in 55% of cases, although only one case was performed in the delivery suite, while all others were performed in the operating room. Echocardiography was performed in 60% of the cases and all were pathological. Furthermore, 20% of cases were connected to an extracorporeal membrane oxygenation machine. There was a 15% mortality rate of 15%. A further 15% suffered major neurological disability, 25% suffered minor neurological morbidity, and 45% survived without severe complications. CONCLUSION: AFE is associated with significant maternal morbidity. This study highlights the importance of providing advanced training for the delivery suite staff for cases of maternal cardiovascular collapse secondary to AFE and increasing awareness for this rare and devastating obstetric condition.

Risk factors for fatality in amniotic fluid embolism: a systematic review and analysis of a data pool.

PURPOSE: Investigating risk factors for amniotic fluid embolism (AFE)-induced fatality. METHODS: A systematic review of cases of AFE available on PubMed, Scielo, Scopus and AJOL databases that occurred from 1990 to 2015 was carried out. After careful reading of titles, abstracts and full texts, case reports of AFE were reviewed. Risk factors for AFE were considered as independent variables in logistic regression models. The first model was built on the whole data pool. The second model was built on typical cases of AFE, according to the classical triad of symptoms (heart, lungs, coagulopathy). The dependent variable was fatality in both models. RESULTS: 177 cases of AFE were assessed in the first model, while 121 typical cases of AFE were assessed in the second model. Among typical cases of AFE, only oxytocin infusion during labour increases the likelihood of death (odds ratio 2.890, 95% confidence interval 1.166-7.164, p = 0.022). No risk factors for fatality were found in the whole data pool. CONCLUSIONS: Further research on national registries should focus on the behaviour of oxytocin infusion during labour in AFE cases.

Maternal Death Due to Amniotic Fluid Embolism: A National Study in France.

BACKGROUND: A structured definition of amniotic fluid embolism (AFE) based on 4 criteria was recently proposed for use in research by the Society for Maternal-Fetal Medicine (SMFM) and the Amniotic Fluid Embolism Foundation. The main objective of this study was to review all AFE-related maternal deaths in France during 2007-2011 according to the presence or not of all these 4 diagnostic criteria. METHODS: Maternal deaths due to AFE were identified by the national experts committee of the French Confidential Enquiry into Maternal Deaths during 2007-2011 (n = 39). The maternal mortality ratio for AFE was calculated. We applied the structured definition proposed by the Society for Maternal-Fetal Medicine and the Amniotic Fluid Embolism Foundation to AFE-related maternal deaths identified by the national experts committee. Characteristics of women, pregnancies and deliveries; clinical and biological features of AFE; and specific laboratory tests used were described by the presence or not of all 4 diagnostic criteria. Management of obstetric hemorrhage and quality of care according to the experts were also described. RESULTS: The maternal mortality ratio from AFE was 0.95/100,000 live births (95% confidence interval, 0.67-1.3). Detailed clinical data were collected for 36 women who died from AFE: 21 (58%) had all 4 proposed diagnostic criteria and 15 (42%) had 1 or more missing criterion. Documented early disseminated intravascular coagulopathy was missing for 14 women, and 2 women exhibited more than 1 missing criterion. Ten of the 15 women with missing criteria had clinical coagulopathy, with standard hemostasis tests performed in only 3. Specific diagnostic examinations for AFE were performed in similar proportions by the presence or not of all diagnostic criteria. Opportunities to improve care included timely performance of indicated hysterectomy (n = 13) and improved transfusion practices (n = 9). In the context of maternal cardiac arrest, for 5 of 13 women, fetal extraction was performed within 5 minutes. CONCLUSIONS: The structured definition of AFE for research studies would exclude more than one-third of AFE-related maternal deaths identified by the national experts committee. Inclusion of clinical coagulopathy as a diagnostic criterion for AFE would reduce this proportion to 14%. There is still room for improvement in the management of obstetric hemorrhage and timely fetal extraction in the context of maternal cardiac arrest, frequently observed in AFE-related maternal death.

Perinatal Maternal Mortality in Sickle Cell Anemia: Two Case Reports and Review of the Literature.

As outcomes of patients with sickle cell anemia improve and survival into adulthood with good quality of life and expectation of long-term survival becomes more common, challenges have developed, including issues related to reproduction. Pregnancy is frequently complicated in patients with sickle cell anemia with mortality up to 4.0%. Here we report maternal perinatal mortality in two women with sickle cell anemia who died post-partum due to acute chest syndrome (ACS), caused by bone marrow fat embolism and review the literature pertinent to this subject. Patient A was a 28-year-old woman with sickle cell anemia with multiple complications. At 30 weeks' gestation she developed hemolysis associated with poor placental function necessitating delivery by C-section. The fetus was delivered successfully but she died due to multi organ failure after delivery. Autopsy showed pulmonary and amniotic fluid embolization. Patient B was a 37-year-old woman with uncomplicated sickle cell anemia who presented with pre term labor and crisis, then ACS and fetal distress. The infant was delivered successfully but the patient died after cardiovascular collapse. Autopsy results showed fat and bone marrow embolization as the cause of death. Pregnancy continues to be high risk for patients with sickle cell anemia including those with mild disease. Maternal perinatal mortality could be unpredictable due to serious complications of sickle cell disease. More studies to assess maternal perinatal mortality are needed.

Amniotic fluid embolism mortality rate.

AIM: The objective of this study was to determine the mortality rate of amniotic fluid embolism (AFE) using population-based studies and case series. METHODS: A literature search was conducted using the two key words: 'amniotic fluid embolism (AFE)' AND 'mortality rate'. Thirteen population-based studies were evaluated, as well as 36 case series including at least two patients. RESULTS: The mortality rate from population-based studies varied from 11% to 44%. When nine population-based studies with over 17 000 000 live births were aggregated, the maternal mortality rate was 20.4%. In contrast, the mortality rate of AFE in case series varies from 0% to 100% with numerous rates in between. CONCLUSION: The AFE mortality rate in population-based studies varied from 11% to 44% with the best available evidence supporting an overall mortality rate of 20.4%. Data from case series should no longer be used as a basis for describing the lethality of AFE.

Assessing malpractice lawsuits for death or injuries due to amniotic fluid embolism.

Amniotic fluid embolism (AFE) is a pregnancy complication known to be extremely hard to diagnose, since it manifests itself abruptly and with no warning signs, presenting an incidence rate of about 1 in 40000 deliveries, and maternal morbidity and mortality ranging from 20% to 60%. Although almost a century has gone by since it was first identified (1926) and despite medical research having been conducted on such a syndrome, diagnostic procedures and treatment methods have not yet been clarified enough. Specific biochemical markers have been produced in research laboratories, but their clinical value results to be limited, given how rapid the pathological process moves forward. At the time being, no diagnosis is feasible which may effectively prevent the disease from occurring. Certainly, a multidisciplinary approach might contribute to saving the lives of mother and infant, as well as ensuring better life standards. The paper's authors aim to highlight the medico-legal issues, in light of several rulings from the Italian Constitutional Court as well as lower courts. The authors also advocate for the creation of a nation-wide registry meant to collect all signaled AFE instances so that research on this as yet devastating syndrome can be conducted based on hard data.

[Analysis of maternal morbidity and mortality in Slovak Republic in the years 2007-2012]. / Analýza materskej morbidity a mortality v Slovenskej republike v rokoch 2007-2012.

OBJECTIVE: Analysis of maternal morbidity and mortality in Slovak Republic (SR) in the years 2007-2012. DESIGN: Epidemiological perinatological nation-wide. SETTINGS: 1st Department of Gynaecology and Obstetrics School of Medicine, Comenius University and University Hospital, Bratislava, Slovak Republic. METHODS: The analysis of selected maternal morbidity and mortality data prospective collected in the years 2007-2012 from all obstetrics hospitals in the Slovak Republic. RESULTS: Caesarean section rate progressively increased from 24.1% in the year 2007 up to 30.3% in the year 2012. In the year 2012 the frequency of vacuum-extraction was 1.4%, forceps 0.6%, perineal tears 3th and 4th degree 0.49% and episiotomy 65%. Incidence of total severe acute maternal morbidity was 6.34 per 1,000 births. Incidence (per 1,000 births) of transport to anaesthesiology department/intensive care unit was 2.32, postpartum hysterectomy 0.72, HELLP syndrome 0.63, eclampsia 0.29, abnormal placental invasion 0.37, uterine rupture 0.27, severe sepsis in pregnancy and puerperium 0.21. In the years 2007-2012 frequency of fatal amniotic fluid embolism was 2.46/100,000 maternities or 2.43/100,000 live-births. Maternal mortality ratio in this period was 14 per 100,000 live births and pregnancy-related deaths ratio was 11.9 per 100,000 live births. CONCLUSION: In the year 2012 Slovakia reached the highest caesarean section rate in her own history - 30.3%. Incidence of severe acute maternal morbidity was 6.34 per 1,000 births. Maternal mortality ratio in Slovakia was one of the highest in European Union. Decreasing of caesarean section rate and episiotomy, incidence of severe acute maternal morbidity and maternal mortality still need to be improved in Slovak Republic.

Value of fibrinogen in cases of maternal death related to amniotic fluid embolism.

BACKGROUND: This study aimed to investigate the rate of coagulopathy progression in amniotic fluid embolism (AFE), using the level of fibrinogen. METHODS: We examined all cases of maternal death (46 cases) related to AFE between 2010 and 2013 in Japan (total number of deliveries: 4,291,459). Fibrinogen, blood loss from AFE onset to fibrinogen measurement, and time from onset to fibrinogen measurement were investigated. The correlations of fibrinogen with time from onset to fibrinogen measurement and blood loss at fibrinogen measurement were analyzed. RESULTS: Fibrinogen was undetectable (less than 50 mg/dL) in 14 cases (93%) and 65 mg/dL in one case (7%). All the cases involving not less than 1000 mL of blood loss or within 60 min from onset to fibrinogen measurement demonstrated low levels of fibrinogen. CONCLUSIONS: Coagulopathy in AFE was not directly proportional to bleeding. Furthermore, coagulopathy in AFE developed in a remarkably short length of time. If AFE is suspected, fibrinogen level should be measured rapidly for favoring a more AFE to decrease the risk of death from AFE. And, rapid treatment of coagulopathy can help reduce mortality from AFE.

Efficacy of transfusion with fresh-frozen plasma:red blood cell concentrate ratio of 1 or more for amniotic fluid embolism with coagulopathy: a case-control study.

BACKGROUND: The Japan Association of Obstetricians and Gynecologists (JAOG) recommends transfusion with a fresh-frozen plasma (FFP):red blood cell (RBC) ratio of 1 or more in postpartum hemorrhage. However, no global consensus exists concerning this, and little is known regarding the impact of FFP:RBC ratio on maternal mortality. This study evaluates the efficacy of transfusion with FFP:RBC ratio of 1 or more for amniotic fluid embolism (AFE) with coagulopathy. STUDY DESIGN AND METHODS: The Maternal Death Exploratory Committee, established by the JAOG, conducted this retrospective nationwide case-control study in Japan. Women with AFE and coagulopathy were included in the study and were stratified into survival and death groups. Obstetric variables and therapy methods (hysterectomy, uterine artery embolism, and transfusion with FFP:RBC ratio ≥ 1) were compared between the survival and death groups. RESULTS: A total of 54 women had AFE and coagulopathy (death group, n = 22; survival group, n = 32). Only nine (40.9%) women in the death group were transfused with FFP:RBC ratio of 1 or more, whereas 29 (90.6%) women in the survival group were transfused with FFP:RBC ratio of 1 or more. FFP:RBC ratio of 1 or more was found to be associated with better survival rate (adjusted odds ratio, 28.32; 95% confidence interval, 4.26-188.37). No difference was found in obstetric variables, hysterectomy, and uterine artery embolism between survival and death groups. CONCLUSION: Transfusion with FFP:RBC ratio of 1 or more is associated with higher survival rate in women with AFE with coagulopathy.

Amniotic fluid embolism as a cause of maternal mortality in China between 1996 and 2013: a population-based retrospective study.

BACKGROUND: To analyse the maternal mortality ratio, demographic and pregnancy related details in women who suffered a fatal amniotic fluid embolism (AFE) in China. METHODS: A retrospective population based study using data collected as part of the National Maternal Mortality Surveillance System between 1996 and 2013. Data were collected onto a standardised form from women whose cause of death was listed as being secondary to AFE. RESULTS: Records were available for 640 deaths. Over the 17 year period the maternal mortality ratio for AFE decreased from 4.4 per 100,000 births (95 % confidence interval (CI):2.72-6.12) to 1.9 per 100,000 births (95 % CI:1.35-2.54). Over the same period the proportion of maternal deaths secondary to AFE increased from 6.8 to 12.5 %. The mean age of women who died was 30.1 years and the onset of the AFE occurred prior to delivery in 39 %. The most prominent presenting features included premonitory symptoms (29 %), acute fetal compromise (28 %), maternal haemorrhage (16 %) and shortness of breath (15 %). CONCLUSIONS: Maternal mortality secondary to AFE has decreased in China, however at a slower rate than mortality secondary to other conditions. Active surveillance is recommended to assess case fatality rates, risk factors and other lessons specific to this population.

Pregnancy-associated Deaths: 31-year Experience.

AIM: The aim of the present study was to elucidate the clinical characteristics of pregnancy-associated maternal deaths. METHODS: We performed a retrospective analysis with medical records and autopsy reports of cases of pregnancy-associated deaths. We collected information on all maternal deaths related to pregnancy that occurred in 3 hospitals affiliated with Nippon Medical School in Japan from January 1, 1984, to December 31, 2014. Data analyzed were maternal age, past medical history, parity, gestational age, clinical signs and symptoms, cause of death, and maternal autopsy findings. RESULTS: A total of 26 maternal deaths occurred during the 31-year study period. Autopsies were performed for 16 patients (61.5%). The 26 deaths included 19 (73.1%) classified as direct maternal deaths and 7 (26.9%) classified as indirect maternal deaths. The mean maternal age at death was 33.1±4.3 years (range, 26-41 years). The highest percentage of women was aged 35 to 39 years (38.5%). Of the 26 maternal deaths, 69% occurred at 32 to 41 weeks of gestation. In cases of direct maternal death, the leading causes were amniotic fluid embolism (7 cases, 27.0% of all deaths) and hemorrhage (6 cases, 23.1% of all deaths). In cases of indirect obstetric deaths, the causes included cardiovascular disorders, cerebrovascular disorders, sepsis due to group A streptococcal infection, and hepatic failure of unknown etiology. CONCLUSIONS: Amniotic fluid embolism was the leading cause of maternal deaths and was followed by obstetric hemorrhage. To prevent and reduce the number of maternal deaths in Japan, further basic and clinical research on amniotic fluid embolism is required.

Incidence, risk factors, management and outcomes of amniotic-fluid embolism: a population-based cohort and nested case-control study.

OBJECTIVE: To describe the incidence, risk factors, management and outcomes of amniotic-fluid embolism (AFE) over time. DESIGN: A population-based cohort and nested case-control study using the UK Obstetric Surveillance System (UKOSS). SETTING: All UK hospitals with obstetrician-led maternity units. POPULATION: All women diagnosed with AFE in the UK between February 2005 and January 2014 (n = 120) and 3839 control women. METHODS: Prospective case and control identification through UKOSS monthly mailing. MAIN OUTCOME MEASURES: Amniotic-fluid embolism, maternal death or permanent neurological injury. RESULTS: The total and fatal incidence of AFE, estimated as 1.7 and 0.3 per 100 000, respectively, showed no significant temporal trend over the study period and there was no notable temporal change in risk factors for AFE. Twenty-three women died (case fatality 19%) and seven (7%) of the surviving women had permanent neurological injury. Women who died or had permanent neurological injury were more likely to present with cardiac arrest (83% versus 33%, P < 0.001), be from ethnic-minority groups (adjusted odds ratio [OR] 2.85, 95% confidence interval [95% CI] 1.02-8.00), have had a hysterectomy (unadjusted OR 2.49, 95% CI 1.02-6.06), had a shorter time interval between the AFE event and when the hysterectomy was performed (median interval 77 minutes versus 248 minutes, P = 0.0315), and were less likely to receive cryoprecipitate (unadjusted OR 0.30, 95% CI 0.11-0.80). CONCLUSION: There is no evidence of a temporal change in the incidence of or risk factors for AFE. Further investigation is needed to establish whether earlier treatments can reverse the cascade of deterioration leading to severe outcomes.

Underreporting of maternal mortality in Taiwan: A data linkage study.

OBJECTIVE: This study examined the extent to which maternal mortality in Taiwan is underreported in officially published mortality statistics. MATERIALS AND METHODS: We used National Health Insurance claims data collected from two million samples, which were linked with the officially published mortality data, to identify women aged 15-49 years, who were admitted to a hospital with pregnancy-related diagnoses during 2000-2009 and died during the pregnancy or within 42 days after the termination of pregnancy. RESULTS: Based on these linked data, we identified 26 maternal deaths, only nine of which were reported in the original officially published mortality data; thus, the rate of underreporting was 65% [(26 - 9)/26]. The revised maternal mortality ratio was 14.1 deaths per 100,000 live births (95% confidence interval: 8.7-19.5), which was approximately three times higher than the official reported ratio of 4.9 (95% confidence interval: 1.7-8.1). The most common cause of maternal deaths was amniotic fluid embolism (n = 10), followed by eclampsia and preeclampsia (n = 4). CONCLUSION: Approximately two-thirds of the maternal deaths in Taiwan were unreported in the officially published mortality data. Hence, routine nationwide data linkage is essential to monitor maternal mortality in Taiwan accurately.

Amniotic fluid embolism: despite progress, challenges remain.

PURPOSE OF REVIEW: This article reviews the incidence, pathophysiology, risk factors, diagnosis, and management of amniotic fluid embolism (AFE). RECENT FINDINGS: AFE is a leading cause of maternal morbidity and mortality despite an incidence of approximately 7 to 8 per 100,000 births. Recent reevaluation of AFE suggests that the presence of fetal tissue in maternal circulation alone is not sufficient to cause the clinical syndrome, but rather an individual's response to this fetal tissue. The 'anaphylactoid reaction' associated with AFE shares many clinical and metabolic aspects of septic shock. Acute dyspnea followed by cardiovascular collapse, coagulopathy, and neurological symptoms, such as coma and seizures may all be associated with the clinical AFE syndrome. Specific biochemical markers have been described, but are of limited clinical value because of the rapid progression of the disease process. Treatment is based on an interdisciplinary approach that consists of a combination of prompt, aggressive hemodynamic resuscitation, provision of end-organ support, correction of hemostatic disorders, and delivery. SUMMARY: Although AFE cannot be prevented, early diagnosis and intervention may lead to better outcomes for both the mother and the fetus. Clinical suspicion, traditional laboratory data, or intravascular cellular debris (demonstrated only in 50% of patients) are insufficient to make a definitive diagnosis of AFE. An evolving array of novel biomarkers may help differentiate AFE from other conditions, but none of them currently provide sufficient 'early warning' ability to make real-time impact on diagnosis and/or treatment of AFE.

Pregnancy-related mortality in California: causes, characteristics, and improvement opportunities.

OBJECTIVE: To compare specific maternal and clinical characteristics and contributing factors among the five leading causes of pregnancy-related mortality to develop focused clinical and public health prevention programs. METHODS: California pregnancy-related deaths from 2002-2005 were identified with enhanced surveillance using linked birth and death certificates. A multidisciplinary committee reviewed medical records, autopsy reports, and coroner reports to determine cause of death, clinical and demographic characteristics, chance to alter outcome, contributing factors (at health care provider, facility, and patient levels), and quality improvement opportunities. The five leading causes of death were compared with each other and with the overall California birth population. RESULTS: Among the 207 pregnancy-related deaths, the five leading causes were cardiovascular disease, preeclampsia or eclampsia, hemorrhage, venous thromboembolism, and amniotic fluid embolism. Among the leading causes of death, we identified differing patterns for race, maternal age, body mass index, timing of death, and method of delivery. Overall, there was a good-to-strong chance to alter the outcome in 41% of deaths, with the highest rates of preventability among hemorrhage (70%) and preeclampsia (60%) deaths. Health care provider, facility, and patient contributing factors also varied by cause of death. CONCLUSION: Pregnancy-related mortality should not be considered a single clinical entity. Reducing mortality requires in-depth examination of individual causes of death. The five leading causes exhibit different characteristics, degrees of preventability, and contributing factors, with the greatest improvement opportunities identified for hemorrhage and preeclampsia. These findings provide additional support for hospital, state, and national maternal safety programs.

Factors associated with maternal death from direct pregnancy complications: a UK national case-control study.

OBJECTIVE: To investigate the factors associated with maternal death from direct pregnancy complications in the UK. DESIGN: Unmatched case-control analysis. SETTING: All hospitals caring for pregnant women in the UK. POPULATION: A total of 135 women who died (cases) between 2009 and 2012 from eclampsia, pulmonary embolism, severe sepsis, amniotic fluid embolism, and peripartum haemorrhage, using data from the Confidential Enquiry into Maternal Death, and another 1661 women who survived severe complications (controls) caused by these conditions (2005-2013), using data from the UK Obstetric Surveillance System. METHODS: Multivariable regression analyses were undertaken to identify the factors that were associated with maternal deaths and to estimate the additive odds associated with the presence of one or more of these factors. MAIN OUTCOME MEASURES: Odds ratios associated with maternal death and population-attributable fractions, with 95% confidence intervals. Incremental risk of death associated with the factors using a 'risk factors' score. RESULTS: Six factors were independently associated with maternal death: inadequate use of antenatal care (adjusted odds ratio, aOR 15.87, 95% CI 6.73-37.41); substance misuse (aOR 10.16, 95% CI 1.81-57.04); medical comorbidities (aOR 4.82, 95% CI 3.14-7.40); previous pregnancy problems (aOR 2.21, 95% CI 1.34-3.62); hypertensive disorders of pregnancy (aOR 2.44, 95% CI 1.31-4.52); and Indian ethnicity (aOR 2.70, 95% CI 1.14-6.43). Of the increased risk associated with maternal death, 70% (95% CI 66-73%) could be attributed to these factors. Odds associated with maternal death increased by three and a half times per unit increase in the 'risk factor' score (aOR 3.59, 95% CI 2.83-4.56). CONCLUSIONS: This study shows that medical comorbidities are importantly associated with direct (obstetric) deaths. Further studies are required to understand whether specific aspects of care could be improved to reduce maternal deaths among women with medical comorbidities in the UK.