Maternal mortality in the United States: are the high and rising rates due to changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance?

BACKGROUND: National Vital Statistics System reports show that maternal mortality rates in the United States have nearly doubled, from 17.4 in 2018 to 32.9 per 100,000 live births in 2021. However, these high and rising rates could reflect issues unrelated to obstetrical factors, such as changes in maternal medical conditions or maternal mortality surveillance (eg, due to introduction of the pregnancy checkbox). OBJECTIVE: This study aimed to assess if the high and rising rates of maternal mortality in the United States reflect changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance. STUDY DESIGN: The study was based on all deaths in the United States from 1999 to 2021. Maternal deaths were identified using the following 2 approaches: (1) per National Vital Statistics System methodology, as deaths in pregnancy or in the postpartum period, including deaths identified solely because of a positive pregnancy checkbox, and (2) under an alternative formulation, as deaths in pregnancy or in the postpartum period, with at least 1 mention of pregnancy among the multiple causes of death on the death certificate. The frequencies of major cause-of-death categories among deaths of female patients aged 15 to 44 years, maternal deaths, deaths due to obstetrical causes (ie, direct obstetrical deaths), and deaths due to maternal medical conditions aggravated by pregnancy or its management (ie, indirect obstetrical deaths) were quantified. RESULTS: Maternal deaths, per National Vital Statistics System methodology, increased by 144% (95% confidence interval, 130-159) from 9.65 in 1999-2002 (n=1550) to 23.6 per 100,000 live births in 2018-2021 (n=3489), with increases occurring among all race and ethnicity groups. Direct obstetrical deaths increased from 8.41 in 1999-2002 to 14.1 per 100,000 live births in 2018-2021, whereas indirect obstetrical deaths increased from 1.24 to 9.41 per 100,000 live births: 38% of direct obstetrical deaths and 87% of indirect obstetrical deaths in 2018-2021 were identified because of a positive pregnancy checkbox. The pregnancy checkbox was associated with increases in less specific and incidental causes of death. For example, maternal deaths with malignant neoplasms listed as a multiple cause of death increased 46-fold from 0.03 in 1999-2002 to 1.42 per 100,000 live births in 2018-2021. Under the alternative formulation, the maternal mortality rate was 10.2 in 1999-2002 and 10.4 per 100,000 live births in 2018-2021; deaths from direct obstetrical causes decreased from 7.05 to 5.82 per 100,000 live births. Deaths due to preeclampsia, eclampsia, postpartum hemorrhage, puerperal sepsis, venous complications, and embolism decreased, whereas deaths due to adherent placenta, renal and unspecified causes, cardiomyopathy, and preexisting hypertension increased. Maternal mortality increased among non-Hispanic White women and decreased among non-Hispanic Black and Hispanic women. However, rates were disproportionately higher among non-Hispanic Black women, with large disparities evident in several causes of death (eg, cardiomyopathy). CONCLUSION: The high and rising rates of maternal mortality in the United States are a consequence of changes in maternal mortality surveillance, with reliance on the pregnancy checkbox leading to an increase in misclassified maternal deaths. Identifying maternal deaths by requiring mention of pregnancy among the multiple causes of death shows lower, stable maternal mortality rates and declines in maternal deaths from direct obstetrical causes.

Association of Maternal Influenza Vaccination During Pregnancy With Early Childhood Health Outcomes.

Importance: Seasonal influenza vaccination in pregnancy can reduce influenza illness among pregnant women and newborns. Evidence is limited on whether seasonal influenza vaccination in pregnancy is associated with adverse childhood health outcomes. Objective: To assess the association between maternal influenza vaccination during pregnancy and early childhood health outcomes. Design, Setting, and Participants: Retrospective cohort study, using a birth registry linked with health administrative data. All live births in Nova Scotia, Canada, between October 1, 2010, and March 31, 2014, were included, with follow-up until March 31, 2016. Adjusted hazard ratios (HRs) and incidence rate ratios (IRRs) with 95% confidence intervals were estimated while controlling for maternal medical history and other potential confounders using inverse probability of treatment weighting. Exposures: Seasonal influenza vaccination during pregnancy. Main Outcomes and Measures: Childhood outcomes studied were immune-related (eg, asthma, infections), non-immune-related (eg, neoplasms, sensory impairment), and nonspecific (eg, urgent or inpatient health care utilization), measured from emergency department and hospitalization databases. Results: Among 28 255 children (49% female, 92% born at ≥37 weeks' gestation), 10 227 (36.2%) were born to women who received seasonal influenza vaccination during pregnancy. During a mean follow-up of 3.6 years, there was no significant association between maternal influenza vaccination and childhood asthma (incidence rate, 3.0 vs 2.5 per 1000 person-years; difference, 0.53 per 1000 person-years [95% CI, -0.15 to 1.21]; adjusted HR, 1.22 [95% CI, 0.94 to 1.59]), neoplasms (0.32 vs 0.26 per 1000 person-years; difference, 0.06 per 1000 person-years [95% CI, -0.16 to 0.28]; adjusted HR, 1.26 [95% CI, 0.57 to 2.78]), or sensory impairment (0.80 vs 0.97 per 1000 person-years; difference, -0.17 per 1000 person-years [95% CI, -0.54 to 0.21]; adjusted HR, 0.82 [95% CI, 0.49 to 1.37]). Maternal influenza vaccination in pregnancy was not significantly associated with infections in early childhood (incidence rate, 184.6 vs 179.1 per 1000 person-years; difference, 5.44 per 1000 person-years [95% CI, 0.01 to 10.9]; adjusted IRR, 1.07 [95% CI, 0.99 to 1.15]) or with urgent and inpatient health services utilization (511.7 vs 477.8 per 1000 person-years; difference, 33.9 per 1000 person-years [95% CI, 24.9 to 42.9]; adjusted IRR, 1.05 [95% CI, 0.99 to 1.16]). Conclusions and Relevance: In this population-based cohort study with mean follow-up duration of 3.6 years, maternal influenza vaccination during pregnancy was not significantly associated with an increased risk of adverse early childhood health outcomes.

Maternal Mortality in the United States: Recent Trends, Current Status, and Future Considerations.

Rigorous studies carried out by the National Center for Health Statistics show that previously reported increases in maternal mortality rates in the United States were an artifact of changes in surveillance. The pregnancy checkbox, introduced in the revised 2003 death certificate and implemented by the states in a staggered manner, resulted in increased identification of maternal deaths and in reported maternal mortality rates. This Commentary summarizes the findings of the National Center for Health Statistics reports, describes temporal trends and the current status of maternal mortality in the United States, and discusses future concerns. Although the National Center for Health Statistics studies, based on recoding of death certificate information (after excluding information from the pregnancy checkbox), showed that crude maternal mortality rates did not change significantly between 2002 and 2018, age-adjusted analyses show a temporal reduction in the maternal mortality rate (21% decline, 95% CI 13-28). Specific causes of maternal death, which were not affected by the pregnancy checkbox, such as preeclampsia, showed substantial temporal declines. However, large racial disparities continue to exist: Non-Hispanic Black women had a 2.5-fold higher maternal mortality rate compared with non-Hispanic White women in 2018. This overview of maternal mortality underscores the need for better surveillance and more accurate identification of maternal deaths, improved clinical care, and expanded public health initiatives to address social determinants of health. Challenges with ascertaining maternal deaths notwithstanding, several causes of maternal death (unaffected by surveillance artifacts) show significant temporal declines, even though there remains substantial scope for preventing avoidable maternal death and reducing disparities.

Neonatal Abstinence Syndrome and Associated Neonatal and Maternal Mortality and Morbidity.

OBJECTIVES: We examined demographic characteristics and birth outcomes of infants with neonatal abstinence syndrome (NAS) and their mothers in Canada. METHODS: This retrospective, population-based, descriptive cross-sectional study of mother-infant dyads included all singleton live births in Canada (excluding Quebec), from 2005-2006 to 2015-2016 (N = 2 881 789). Demographic characteristics, NAS, and neonatal and maternal morbidities were identified from delivery hospitalization data (including diagnostic codes). The main composite outcomes were maternal and neonatal mortality and/or severe morbidity, including death and potentially life-threatening conditions in the mother and the infant, respectively. Logistic regression yielded adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: The study included 10 027 mother-infant dyads with NAS. The incidence of NAS increased from 0.20% to 0.51%. Maternal mortality was 1.99 vs 0.31 per 10 000 women in the NAS group versus the comparison group (aOR = 6.53; 95% CI: 1.59 to 26.74), and maternal mortality and/or severe morbidity rates were 3.10% vs 1.35% (aOR = 2.21; 95% CI: 1.97 to 2.49). Neonatal mortality was 0.12% vs 0.19% (aOR = 0.28; 95% CI: 0.15 to 0.53), and neonatal mortality and/or severe morbidity rates were 6.36% vs 1.73% (aOR = 2.27; 95% CI: 2.06 to 2.50) among infants with NAS versus without NAS. CONCLUSIONS: NAS incidence increased notably in Canada between 2005-2006 and 2015-2016. Infants with NAS had elevated severe morbidity, and their mothers had elevated mortality and severe morbidity. These results highlight the importance of implementing integrated care services to support the mother-infant dyad during childbirth and in the postpartum period.

Domperidone for insufficient lactation in England 2002-2015: A drug utilization study with interrupted time series analysis.

PURPOSE: Our aim was to describe trends in the prescription of domperidone for insufficient lactation in England, the characteristics of women prescribed it postpartum, and the impact of a 2014 European Medicines Agency (EMA) recommendation to restrict its use due to a potential increased risk of sudden cardiac death associated with its use. METHODS: We conducted a population-based cohort study with interrupted time series analysis using data from the Clinical Practice Research Datalink linked to Hospital Episode Statistics. We identified women with live births from 2002 to 2015, excluding those with nonlactation indications for domperidone (n = 247 349). We evaluated trends in the prescription rate of domperidone in the 6 months postpartum and differences in this rate before and after the EMA recommendation. RESULTS: Domperidone was prescribed among 1438 deliveries at a rate of 1.24 per 100 person-years. This rate increased from 0.56 to 2.1 per 100 person-years between 2002-2004 and 2011-2013 (rate ratio: 3.8; 95% confidence interval [CI], 3.2-4.6). Prescribing decreased in level by 0.35 (95% CI, -0.86 to 0.16) per 100 person-years immediately following the recommendation with little change in trend (0.003; 95% CI, -0.059 to 0.065 per 100 person-years). Following the recommendation, prescription of doses >30 mg and coprescription of drugs with a risk of torsade de pointes decreased. No arrhythmic events were observed among domperidone users. CONCLUSIONS: Although we observed an important increase in prescribing during the study period, domperidone remains infrequently prescribed postpartum in England. While overall prescribing changed little, some prescribing practices became more restricted following the EMA's recommendation.

Factors Underlying the Temporal Increase in Maternal Mortality in the United States.

OBJECTIVE: To identify the factors underlying the recent increase in maternal mortality ratios (maternal deaths per 100,000 live births) in the United States. METHODS: We carried out a retrospective study with data on maternal deaths and live births in the United States from 1993 to 2014 obtained from the birth and death files of the Centers for Disease Control and Prevention. Underlying causes of death were examined between 1999 and 2014 using International Classification of Diseases, 10th Revision (ICD-10) codes. Poisson regression was used to estimate maternal mortality rate ratios (RRs) and 95% confidence intervals (CIs) after adjusting for the introduction of a separate pregnancy question and the standard pregnancy checkbox on death certificates and adoption of ICD-10. RESULTS: Maternal mortality ratios increased from 7.55 in 1993, to 9.88 in 1999, and to 21.5 per 100,000 live births in 2014 (RR 2014 compared with 1993 2.84, 95% CI 2.49-3.24; RR 2014 compared with 1999 2.17, 95% CI 1.93-2.45). The increase in maternal deaths from 1999 to 2014 was mainly the result of increases in maternal deaths associated with two new ICD-10 codes (O26.8, ie, primarily renal disease; and O99, ie, other maternal diseases classifiable elsewhere); exclusion of such deaths abolished the increase in mortality (RR 1.09, 95% CI 0.94-1.27). Regression adjustment for improvements in surveillance also abolished the temporal increase in maternal mortality ratios (adjusted maternal mortality ratios 7.55 in 1993, 8.00 per 100,000 live births in 2013; adjusted RR 2013 compared with 1993 1.06, 95% CI 0.90-1.25). CONCLUSION: Recent increases in maternal mortality ratios in the United States are likely an artifact of improvements in surveillance and highlight past underestimation of maternal death. Complete ascertainment of maternal death in populations remains a challenge even in countries with good systems for civil registration and vital statistics.

Atonic Postpartum Hemorrhage: Blood Loss, Risk Factors, and Third Stage Management.

OBJECTIVE: Atonic postpartum hemorrhage rates have increased in many industrialized countries in recent years. We examined the blood loss, risk factors, and management of the third stage of labour associated with atonic postpartum hemorrhage. METHODS: We carried out a case-control study of patients in eight tertiary care hospitals in Canada between January 2011 and December 2013. Cases were defined as women with a diagnosis of atonic postpartum hemorrhage, and controls (without postpartum hemorrhage) were matched with cases by hospital and date of delivery. Estimated blood loss, risk factors, and management of the third stage labour were compared between cases and controls. Conditional logistic regression was used to adjust for confounding. RESULTS: The study included 383 cases and 383 controls. Cases had significantly higher mean estimated blood loss than controls. However, 16.7% of cases who delivered vaginally and 34.1% of cases who delivered by Caesarean section (CS) had a blood loss of < 500 mL and < 1000 mL, respectively; 8.2% of controls who delivered vaginally and 6.7% of controls who delivered by CS had blood loss consistent with a diagnosis of postpartum hemorrhage. Factors associated with atonic postpartum hemorrhage included known protective factors (e.g., delivery by CS) and risk factors (e.g., nulliparity, vaginal birth after CS). Uterotonic use was more common in cases than in controls (97.6% vs. 92.9%, P < 0.001). Delayed cord clamping was only used among those who delivered vaginally (7.7% cases vs. 14.6% controls, P = 0.06). CONCLUSION: There is substantial misclassification in the diagnosis of atonic postpartum hemorrhage, and this could potentially explain the observed temporal increase in postpartum hemorrhage rates.

Heterogeneity of respiratory distress syndrome: risk factors and morbidity associated with early and late gestation disease.

BACKGROUND: Although respiratory distress syndrome (RDS) is considered a disease of prematurity, there is evidence to suggest heterogeneity between early and late gestation RDS. We examined the epidemiologic features of RDS occurring at early and late gestation. METHODS: We conducted a retrospective cohort study including live births in the United States in 2005-06, with information obtained from the National Center for Health Statistics. Early (<32 weeks) and late gestation RDS (≥39 weeks) were contrasted in terms of risk factors and associations with pregnancy complications, obstetric intervention and co-morbidity. Logistic regression was used to quantify the effects of risk factors, while other associations were quantified descriptively. RESULTS: There were 27,971 RDS cases, yielding an incidence of 6.4 per 1000 live births. Early and late gestation RDS differed in terms of risk factors, with factors such as multi-fetal gestation more strongly associated with early (adjusted odds ratio [aOR] 11.6, 95 % confidence interval 11.0-12.2) compared with late gestation RDS (aOR 3.66, 95 % confidence interval 2.68-4.98). The morbidity correlates of early and late gestation RDS also differed substantially; neonatal seizures were less strongly associated with early (OR 5.90, 95 % confidence interval 3.67-9.47) compared with late gestation RDS (OR 33.1, 95 % confidence interval 27.2-40.2), while meconium aspiration syndrome was not significantly associated with early gestation RDS (OR 1.87, 95 % confidence interval 0.94-3.72) and very strongly associated with late gestation RDS (OR 39.8, 95 % confidence interval 34.7-45.6). CONCLUSIONS: Differences in risk factors and morbidity correlates of early and late gestation RDS suggest that these entities represent two distinct diseases.

Investigation of a Rise in Obstetric Acute Renal Failure in the United States, 1999-2011.

OBJECTIVE: To estimate whether the reported increase in obstetric acute renal failure in the United States was attributable to a concurrent rise in postpartum hemorrhage, a change in other risk factors, or changes in the diagnosis of acute renal failure. METHODS: We conducted a retrospective cohort study to quantify temporal trends in acute renal failure among 10,969,263 hospital deliveries in the United States from 1999 to 2011 using data from the Nationwide Inpatient Sample. Dialysis and maternal death were used as markers of severe acute renal failure. Logistic regression was used to determine whether changes in risk factors explained the temporal rise in acute renal failure. RESULTS: Obstetric acute renal failure rose from 2.4 to 6.3 per 10,000 deliveries between 1999-2001 and 2010-2011, a 10% yearly increase (95% confidence interval [CI] 8-11%) and adjustment for risk factors only partially explained the rise (adjusted yearly increase 6%, 95% CI 5-8%). The overall severity of acute renal failure decreased, although acute renal failure with dialysis rose from 0.27 to 0.36 per 10,000 deliveries (P for trend=.01), and acute renal failure associated with maternal death increased from 0.13 to 0.23 per 10,000 deliveries (P for trend=.01). The temporal increase in acute renal failure with dialysis was abolished by adjustment for chronic kidney disease and chronic hypertension. CONCLUSION: Changes in diagnosis or ascertainment have led to substantial increases in obstetric acute renal failure, whereas increases in chronic kidney disease and chronic hypertension among pregnant women have resulted in modest but significant increases in acute renal failure with dialysis.

Can drug effects explain the recent temporal increase in atonic postpartum haemorrhage?

BACKGROUND: Rates of postpartum haemorrhage and atonic postpartum haemorrhage have increased in several high-income countries. We carried out a study to examine if drug use in pregnancy, or drug and other interactions, explained this increase in postpartum haemorrhage. METHODS: The linked administrative and hospital databases of the Québec Pregnancy Cohort were used to define a cohort of pregnant women in Québec, Canada, from 1998 to 2009 (n = 138,704). Case-control studies on any postpartum haemorrhage and atonic postpartum haemorrhage were carried out within this population, with up to five controls randomly selected for each case after matching on index date and hospital of delivery (incidence density sampling). Conditional logistic regression was used to estimate the effects of drug use on postpartum haemorrhage and atonic postpartum haemorrhage. RESULTS: There was an unexpected non-linear, declining temporal pattern in postpartum haemorrhage and atonic postpartum haemorrhage between 1998 and 2009. Use of antidepressants (mainly selective serotonin reuptake inhibitors) was associated with higher rates of postpartum haemorrhage [adjusted rate ratio (aRR) 1.48, 95% confidence interval (CI) 1.23, 1.77] and atonic postpartum haemorrhage [aRR 1.40, 95% CI 1.13, 1.74]. Thrombocytopenia was also associated with higher rates of postpartum haemorrhage [aRR 1.52, 95% CI 1.16, 2.00]. There were no statistically significant drug interactions. Adjustment for maternal factors and drug use had little effect on temporal trends in postpartum haemorrhage and atonic postpartum haemorrhage. CONCLUSIONS: Although antidepressant use and thrombocytopenia were associated with higher rates of atonic postpartum haemorrhage, antidepressant and other drug use did not explain temporal trends in postpartum haemorrhage.

Contribution of placenta accreta to the incidence of postpartum hemorrhage and severe postpartum hemorrhage.

OBJECTIVE: To quantify the contribution of placenta accreta to the rate of postpartum hemorrhage and severe postpartum hemorrhage. METHODS: All hospital deliveries in Canada (excluding Quebec) for the years 2009 and 2010 (N=570,637) were included in a retrospective cohort study using data from the Canadian Institute for Health Information. Placenta accreta included placental adhesion to the uterine wall, musculature, and surrounding organs (accreta, increta, or percreta). Severe postpartum hemorrhage included postpartum hemorrhage with blood transfusion, hysterectomy, or other procedures to control bleeding (including uterine suturing and ligation or embolization of pelvic arteries). Rates, rate ratios, population-attributable fractions (ie, incidence of postpartum hemorrhage attributable to placenta accreta), and 95% confidence intervals (CIs) were estimated. Logistic regression was used to quantify associations between placenta accreta and risk factors. RESULTS: The incidence of placenta accreta was 14.4 (95% CI 13.4-15.4) per 10,000 deliveries (819 cases among 570,637 deliveries), whereas the incidence of placenta accreta with postpartum hemorrhage was 7.2 (95% CI 6.5-8.0) per 10,000 deliveries. Postpartum hemorrhage among women with placenta accreta was predominantly third-stage hemorrhage (41% of all cases). Although placenta accreta was strongly associated with postpartum hemorrhage (rate ratio 8.3, 95% CI 7.7-8.9), its low frequency resulted in a small population-attributable fraction (1.0%, 95% CI 0.93-1.16). However, the strong association between placenta accreta and postpartum hemorrhage with hysterectomy (rate ratio 286, 95% CI 226-361) resulted in a population-attributable fraction of 29.0% (95% CI 24.3-34.3). CONCLUSION: Placenta accreta is too infrequent to account for the recent temporal increase in postpartum hemorrhage but contributes substantially to the proportion of postpartum hemorrhage with hysterectomy.

Rationalizing definitions and procedures for optimizing clinical care and public health in fetal death and stillbirth.

Despite the recent focus on stillbirth, there remains a profound need to address problems associated with the definitions and procedures related to fetal death and stillbirth. The current definition of fetal death, first proposed in 1950, needs to be updated to distinguish between the timing of fetal death (which has etiologic and prognostic significance) and the timing of stillbirth (ie, the delivery of the dead fetus). Stillbirth registration procedures, modeled after live birth registration and not death registration, also need to be modernized because they can be an unnecessary burden on some grieving families. The problems associated with fetal death definitions and stillbirth-associated procedures are highlighted by selective fetal reduction in multifetal pregnancy; in many countries, the fetus reduced at 10-13 weeks of gestation and delivered at term gestation requires stillbirth registration and a burial permit even if fetal remains cannot be identified. An international consensus is needed to standardize the definition of reportable fetal deaths; ideally this should be based on the timing of fetal death and should address the status of pregnancy terminations. In this article, we list propositions for initiating an international dialogue that will rationalize fetal death definitions, registration criteria, and associated procedures, and thereby improve clinical care and public health.

Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study.

OBJECTIVE: To examine whether changes in postpartum haemorrhage, hypertensive disorders of pregnancy, or other risk factors explain the increase in obstetric acute renal failure in Canada. DESIGN: Retrospective cohort study. SETTING: Canada (excluding the province of Quebec). PARTICIPANTS: All hospital deliveries from 2003 to 2010 (n=2,193,425). MAIN OUTCOME MEASURES: Obstetric acute renal failure identified by ICD-10 diagnostic codes. METHODS: Information on all hospital deliveries in Canada (excluding Quebec) between 2003 and 2010 (n=2,193,425) was obtained from the Canadian Institute for Health Information. Temporal trends in obstetric acute renal failure were assessed among women with and without postpartum haemorrhage, hypertensive disorders of pregnancy, or other risk factors. Logistic regression was used to determine if changes in risk factors explained the temporal increase in obstetric acute renal failure. RESULTS: Rates of obstetric acute renal failure rose from 1.66 to 2.68 per 10,000 deliveries between 2003-04 and 2009-10 (61% increase, 95% confidence interval 24% to 110%). Adjustment for postpartum haemorrhage, hypertensive disorders, and other factors did not attenuate the increase. The temporal increase in acute renal failure was restricted to deliveries with hypertensive disorders (adjusted increase 95%, 95% confidence interval 38% to 176%), and was especially pronounced among women with gestational hypertension with significant proteinuria (adjusted increase 171%, 71% to 329%). No significant increase occurred among women without hypertensive disorders (adjusted increase 12%, -28 to 72%). CONCLUSIONS: The increase in obstetric acute renal failure in Canada between 2003 and 2010 was restricted to women with hypertensive disorders and was especially pronounced among women with pre-eclampsia. Further study is required to determine the cause of the increase among women with pre-eclampsia.

Temporal trends in postpartum hemorrhage and severe postpartum hemorrhage in Canada from 2003 to 2010.

OBJECTIVE: Increases in postpartum hemorrhage have been reported from several countries. We assessed temporal trends in postpartum hemorrhage and severe postpartum hemorrhage in Canada between 2003 and 2010. METHODS: We carried out a population-based cohort study of all hospital deliveries in Canada (excluding Quebec) from 2003 to 2010 (n = 2 193 425), using data from the Canadian Institute for Health Information. Postpartum hemorrhage was defined as a blood loss of ≥ 500 mL following vaginal delivery or ≥ 1000 mL following Caesarean section, or as noted by the care provider. Severe postpartum hemorrhage was defined as postpartum hemorrhage plus blood transfusion, hysterectomy, or other procedures to control bleeding (including uterine suturing or ligation/embolization of pelvic arteries). Temporal trends were assessed using the chi-square test for trend, relative risks, and logistic regression. RESULTS: Postpartum hemorrhage increased by 22% (95% CI 20% to 25%) from 5.1% in 2003 to 6.2% in 2010 (P < 0.001), driven by a 29% increase (95% CI 26% to 33%) in atonic postpartum hemorrhage (3.9% in 2003 vs. 5.0% in 2010, P < 0.001). Postpartum hemorrhage with blood transfusion increased from 36.7 to 50.4 per 10 000 deliveries (P < 0.001), while postpartum hemorrhage with hysterectomy increased from 4.9 to 5.8 per 10 000 deliveries (P < 0.01). Postpartum hemorrhage with uterine suturing, or ligation/embolization of pelvic arteries, increased from 4.1 to 10.7 per 10 000 deliveries (P < 0.001). These increases occurred in most provinces and territories, and could not be explained by changes in maternal, fetal, and obstetric factors. CONCLUSION: Rates of postpartum hemorrhage and severe postpartum hemorrhage continued to increase in Canada between 2003 and 2010.

Objectif : Une hausse des taux d'hémorragie postpartum a été signalée dans plusieurs pays. Nous avons évalué les tendances temporelles en matière d'hémorragie postpartum et d'hémorragie postpartum grave au Canada pour la période se situant entre 2003 et 2010. Méthodes : Nous avons mené une étude de cohorte en population générale ayant porté sur tous les accouchements hospitaliers au Canada (exception faite du Québec) pour la période se situant entre 2003 et 2010 (n = 2 193 425), au moyen des données issues de l'Institut canadien d'information sur la santé. L'hémorragie postpartum a été définie comme étant une perte sanguine ≥ 500 ml à la suite d'un accouchement vaginal ou ≥ 1 000 ml à la suite d'une césarienne, ou encore conformément aux notes du fournisseur de soins. L'hémorragie postpartum grave a été définie comme étant une hémorragie postpartum s'accompagnant d'une transfusion sanguine, d'une hystérectomie ou d'autres interventions visant à juguler les saignements (y compris les sutures utérines ou la ligature / l'embolisation des artères pelviennes). Les tendances temporelles ont été évaluées au moyen d'un test du chi carré (pour ce qui est de l'évolution), des risques relatifs et d'une régression logistique. Résultats : Le taux d'hémorragie postpartum a connu une hausse de 22 % (IC à 95 %, 20 % - 25 %), soit de 5,1 % en 2003 à 6,2 % en 2010 (P < 0,001), déterminée par une hausse de 29 % (IC à 95 %, 26 % - 33 %) du taux d'hémorragie postpartum par atonie utérine (3,9 % en 2003 vs 5,0 % en 2010, P < 0,001). Le taux d'hémorragie postpartum s'accompagnant d'une transfusion sanguine est passé de 36,7 à 50,4 par 10 000 accouchements (P < 0,001), tandis que le taux d'hémorragie postpartum s'accompagnant d'une hystérectomie est passé de 4,9 à 5,8 par 10 000 accouchements (P < 0,01). Le taux d'hémorragie postpartum s'accompagnant de sutures utérines ou d'une ligature / embolisation des artères pelviennes est passé de 4,1 à 10,7 par 10 000 accouchements (P < 0,001). Ces hausses se sont manifestées dans la plupart des provinces et des territoires, et ne pouvaient être expliquées par des modifications affectant des facteurs maternels, fœtaux ou obstétricaux. Conclusion : Les taux d'hémorragie postpartum et d'hémorragie postpartum grave ont poursuivi leur croissance au Canada entre 2003 et 2010.

Incidence, risk factors, and temporal trends in severe postpartum hemorrhage.

OBJECTIVE: Because the diagnosis of postpartum hemorrhage (PPH) depends on the accoucheur's subjective estimate of blood loss and varies according to mode of delivery, we examined temporal trends in severe PPH, defined as PPH plus receipt of a blood transfusion, hysterectomy, and/or surgical repair of the uterus. STUDY DESIGN: We analyzed 8.5 million hospital deliveries in the US Nationwide Inpatient Sample from 1999 to 2008 for temporal trends in, and risk factors for, severe PPH, based on International Classification of Diseases, 9th revision, clinical modification diagnosis and procedure codes. Sequential logistic regression models that account for the stratified random sampling design were used to assess the extent to which changes in risk factors explain the trend in severe PPH. RESULTS: Of the total 8,571,209 deliveries, 25,906 (3.0 per 1000) were complicated by severe PPH. The rate rose from 1.9 to 4.2 per 1000 from 1999 to 2008 (P for yearly trend < .0001), with increases in severe atonic and nonatonic PPH, due especially to PPH with transfusion, but also PPH with hysterectomy. Significant risk factors included maternal age ≥35 years (adjusted odds ratio [aOR], 1.5; 95% confidence interval [CI], 1.5-1.6), multiple pregnancy (aOR, 2.8; 95% CI, 2.6-3.0), fibroids (aOR, 2.0; 95% CI, 1.8-2.2), preeclampsia (aOR, 3.1; 95% CI, 2.9-3.3), amnionitis (aOR, 2.9; 95% CI, 2.5-3.4), placenta previa or abruption (aOR, 7.0; 95% CI, 6.6-7.3), cervical laceration (aOR, 94.0; 95% CI, 87.3-101.2), uterine rupture (aOR, 11.6; 95% CI, 9.7-13.8), instrumental vaginal delivery (aOR, 1.5; 95% CI, 1.4-1.6), and cesarean delivery (aOR, 1.4; 95% CI, 1.3-1.5). Changes in risk factors, however, accounted for only 5.6% of the increase in severe PPH. CONCLUSION: A doubling in incidence of severe PPH over 10 years was not explained by contemporaneous changes in studied risk factors.

Determinants of increases in stillbirth rates from 2000 to 2010.

BACKGROUND: After decades of decline, stillbirth rates have increased in several industrialized countries in recent years. We examined data from the province of British Columbia, Canada, in an attempt to explain this unexpected phenomenon. METHODS: We carried out a retrospective population-based cohort study of all births in British Columbia from 2000 to 2010. Outcomes of interest included overall stillbirth rates, birth weight-and gestational age-specific stillbirth rates, rates of spontaneous stillbirths (excluding pregnancy terminations that satisfied the definition of stillbirth [fetal death with a birth weight ≥ 500 g or gestational age at delivery ≥ 20 wk], hereafter referred to as "pregnancy terminations") and rates of congenital anomalies among live-born infants. We used logistic regression to adjust for changes in maternal age, parity, weight before pregnancy and multiple births. RESULTS: Overall, stillbirth rates increased by 31% (95% confidence interval [CI] 13% to 50%), from 8.08 per 1000 total births in 2000 to 10.55 per 1000 in 2010. The rate of stillbirths with a birth weight of less than 500 g increased significantly (p(trend) = 0.03), whereas the rate of stillbirths with a birth weight of 1000 g or more decreased significantly (p(trend) = 0.009). The rate of spontaneous stillbirths decreased nonsignificantly by 16%, from 5.7 per 1000 total births in 2000 to 4.8 per 1000 in 2010. There was a significant decline of 30% (95% CI 6% to 47%) in the rate of spontaneous stillbirth with a birth weight of 1000 g or more between 2000 and 2010; adjustment for maternal factors did not appreciably change this temporal effect. The prevalence of congenital anomalies among live-born infants decreased significantly, from 5.21 per 100 live births during the first 3 years (2000-02) to 4.77 per 100 during the final 3 years (2008-10). INTERPRETATION: Increases in pregnancy terminations were responsible for the increases observed in stillbirth rates and were associated with declines in the prevalence of congenital anomalies among live-born infants.