A scoping review of severe maternal morbidity: describing risk factors and methodological approaches to inform population-based surveillance

Assessing the relationship between census tract rurality and severe maternal morbidity in California (1997-2018)

PURPOSE

Recent studies have demonstrated an increased risk of severe maternal morbidity (SMM) for people living in rural versus urban counties. Studies have not considered rurality at the more nuanced subcounty census-tract level. This study assessed the relationship between census-tract-level rurality and SMM for birthing people in California.

METHODS

We used linked vital statistics and hospital discharge records for births between 1997 and 2018 in California. SMM was defined by at least 1 of 21 potentially fatal conditions and lifesaving procedures. Rural-Urban Commuting Area codes were used to characterize census tract rurality dichotomously (2-category) and at 4 levels (4-category). Covariates included sociocultural-demographic, pregnancy-related, and neighborhood-level factors. We ran a series of mixed-effects logistic regression models with tract-level clustering, reporting risk ratios and 95% confidence intervals (CIs). We used the STROBE reporting guidelines.

FINDINGS

Of 10,091,415 births, 1.1% had SMM. Overall, 94.3% of participants resided in urban/metropolitan and 5.7% in rural tracts (3.9% micropolitan, 0.9% small town, 0.8% rural). In 2-category models, the risk of SMM was 10% higher for birthing people in rural versus urban tracts (95% CI: 6%, 13%). In 4-category models, the risk of SMM was 16% higher in micropolitan versus metropolitan tracts (95% CI: 12%, 21%).

CONCLUSION

The observed rurality and SMM relationship was driven by living in a micropolitan versus metropolitan tract. Increased risk may result from resource access inequities within suburban areas. Our findings demonstrate the importance of considering rurality at a subcounty level to understand locality-related inequities in the risk of SMM.

Association between stillbirth and severe maternal morbidity

BACKGROUND

Severe maternal morbidity has been increasing in the past few decades. Few studies have examined the risk of severe maternal morbidity among individuals with stillbirths vs individuals with live-birth deliveries.

OBJECTIVE

This study aimed to examine the prevalence and risk of severe maternal morbidity among individuals with stillbirths vs individuals with live-birth deliveries during delivery hospitalization as a primary outcome and during the postpartum period as a secondary outcome.

STUDY DESIGN

This was a retrospective cohort study using birth and fetal death certificate data linked to hospital discharge records from California (2008-2018), Michigan (2008-2020), Missouri (2008-2014), Pennsylvania (2008-2014), and South Carolina (2008-2020). Relative risk regression analysis was used to examine the crude and adjusted relative risks of severe maternal morbidity along with 95% confidence intervals among individuals with stillbirths vs individuals with live-birth deliveries, adjusting for birth year, state of residence, maternal sociodemographic characteristics, and the obstetric comorbidity index.

RESULTS

Of the 8,694,912 deliveries, 35,012 (0.40%) were stillbirths. Compared with individuals with live-birth deliveries, those with stillbirths were more likely to be non-Hispanic Black (10.8% vs 20.5%); have Medicaid (46.5% vs 52.0%); have pregnancy complications, including preexisting diabetes mellitus (1.1% vs 4.3%), preexisting hypertension (2.3% vs 6.2%), and preeclampsia (4.4% vs 8.4%); have multiple pregnancies (1.6% vs 6.2%); and reside in South Carolina (7.4% vs 11.6%). During delivery hospitalization, the prevalence rates of severe maternal morbidity were 791 cases per 10,000 deliveries for stillbirths and 154 cases per 10,000 deliveries for live-birth deliveries, whereas the prevalence rates for nontransfusion severe maternal morbidity were 502 cases per 10,000 deliveries for stillbirths and 68 cases per 10,000 deliveries for live-birth deliveries. The crude relative risk for severe maternal morbidity was 5.1 (95% confidence interval, 4.9-5.3), whereas the adjusted relative risk was 1.6 (95% confidence interval, 1.5-1.8). For nontransfusion severe maternal morbidity among stillbirths vs live-birth deliveries, the crude relative risk was 7.4 (95% confidence interval, 7.0-7.7), whereas the adjusted relative risk was 2.0 (95% confidence interval, 1.8-2.3). This risk was not only elevated among individuals with stillbirth during the delivery hospitalization but also through 1 year after delivery (severe maternal morbidity adjusted relative risk, 1.3; 95% confidence interval, 1.1-1.4; nontransfusion severe maternal morbidity adjusted relative risk, 1.2; 95% confidence interval, 1.1-1.3).

CONCLUSION

Stillbirth was found to be an important contributor to severe maternal morbidity.

Maternal comorbidity index and severe maternal morbidity among medicaid covered pregnant women in a US Southern rural state

BACKGROUND

The rates of SMM have been steadily increasing in Arkansas, a southern rural state, which has the 5th highest maternal death rate among the US states. The aims of the study were to test the functionality of the Bateman index in association to SMM, in clustering the risks of pregnancies to SMM, and to study the predictability of SMM using the Bateman index.

STUDY DESIGN

From the ANGELS database, 72,183 pregnancies covered by Medicaid in Arkansas between 2013 and 2016 were included in this study. The expanded CDC ICD-9/ICD-10 criteria were used to identify SMM. The Bateman comorbidity index was applied in quantifying the comorbidity burden for a pregnancy. Multivariable logistic regressions, KMeans method, and five widely used predictive models were applied respectively for each of the study aims.

RESULTS

SMM prevalence remained persistently high among Arkansas women covered by Medicaid (195 per 10,000 deliveries) during the study period. Using the Bateman comorbidity index score, the study population was divided into four groups, with a monotonically increasing odds of SMM from a lower score group to a higher score group. The association between the index score and the occurrence of SMM is confirmed with statistical significance: relative to Bateman score falling in 0-1, adjusted Odds Ratios and 95% CIs are: 2.1 (1.78, 2.46) for score in 2-5; 5.08 (3.81, 6.79) for score in 6-9; and 8.53 (4.57, 15.92) for score ≥10. Noticeably, more than one-third of SMM cases were detected from the studied pregnancies that did not have any of the comorbid conditions identified. In the prediction analyses, we observed minimal predictability of SMM using the comorbidity index: the calculated c-statistics ranged between 62% and 67%; the Precision-Recall AUC values are <7% for internal validation and <9% for external validation procedures.

CONCLUSIONS

The comorbidity index can be used in quantifying the risk of SMM and can help cluster the study population into risk tiers of SMM, especially in rural states where there are disproportionately higher rates of SMM; however, the predictive value of the comorbidity index for SMM is inappreciable.

The Positive Predictive Value of Hospital Discharge Data for Identifying Severe Maternal Morbidity With and Without Blood Transfusion

BACKGROUND

Blood transfusion is 1 of the 21 indicators for severe maternal morbidity (SMM) as defined by the Centers for Disease Control and Prevention (CDC) using administrative data. The CDC SMM definition is being prepared to measure hospital quality of care; however, transfusion coding reliability has been questioned. The authors assessed the positive predictive value (PPV) of administrative data for identifying gold standard SMM using the CDC SMM definition, with and without the transfusion indicator.

METHODS

A retrospective cohort study of one hospital's childbirth admissions (2016-2019) was performed. Data were screened for CDC SMM, and subgroups were created for those with transfusion as the sole indicator for SMM (transfusion-only SMM) versus those with at least one other SMM indicator (other SMM). Medical chart review classified CDC SMM cases based on gold standard SMM criteria. Gold standard SMM was defined by validated indicators identified by internal hospital quality reviews and confirmed by expert consensus. The PPV was calculated for all CDC SMM cases and the subgroups.

RESULTS

Of 4,212 eligible people, 278 (6.6%) had CDC SMM. Chart review identified 110 gold standard SMM cases among screen-positive cases, yielding an overall PPV of the CDC SMM definition for gold standard SMM of 39.6%. CDC SMM cases identified solely by administrative coding for transfusion were half as likely to meet gold standard criteria, compared to cases identified by other SMM administrative codes (25.9% vs. 49.4%).

CONCLUSION

Blood transfusion, coded as an independent risk factor, had a poor PPV for gold standard SMM. Given efforts to use CDC SMM for quality comparisons, more research is needed to reliably identify cases of SMM without relying on blood transfusion codes.

Using Potentially Preventable Severe Maternal Morbidity to Monitor Hospital Performance

BACKGROUND

The Centers for Disease Control and Prevention (CDC) measure of severe maternal morbidity (SMM) quantifies the burden of SMM but is not restricted to potentially preventable SMM. The authors adapted the CDC SMM measure for this purpose and evaluated it for use as a hospital performance measure.

METHODS

Guidelines for defining performance SMM (pSMM) were (1) exclusion of preexisting conditions from outcome; (2) exclusion of inconsistently documented outcomes; and (3) risk adjustment for conditions that preceded hospitalization. California maternal hospital discharge data from 2016 to 2017 were used for model development, and 2018 data were used for model testing and evaluation of hospital performance. Separate models were developed for hospital types (Community, Teaching, Integrated Delivery System [IDS], and IDS Teaching), generating model-based expected pSMM values. Observed-to-expected (O/E) ratios were calculated for hospitals and used to categorize them as overperforming, average performing, or underperforming using 95% confidence intervals. Performance categories were compared for pSMM vs. CDC SMM (excluding blood transfusion).

RESULTS

The overall 2016-2018 pSMM rate was 0.44%. All hospital types had over- and underperformers, and the proportions of Community, Teaching, IDS, and IDS Teaching hospitals whose performance differed from their performance on the CDC SMM measure were 12.1%, 25.0%, 38.9%, and 66.7%, respectively.

CONCLUSION

The rate of potentially preventable SMM as defined by pSMM (0.44%) was less than half the previously published rate of CDC SMM (1.03%). pSMM identified differences in performance across hospitals, and pSMM and CDC SMM classified hospitals' performances differently. pSMM may be suitable for hospital comparisons because it identifies potentially preventable, hospital-acquired SMM that should be responsive to quality improvement activities.

Severe Maternal Morbidity and Mortality Among Immigrant and Canadian-Born Women Residing Within Low-Income Neighborhoods in Ontario, Canada

IMPORTANCE

Evidence indicates that immigrant women and women residing within low-income neighborhoods experience higher adversity during pregnancy. Little is known about the comparative risk of severe maternal morbidity or mortality (SMM-M) among immigrant vs nonimmigrant women living in low-income areas.

OBJECTIVE

To compare the risk of SMM-M between immigrant and nonimmigrant women residing exclusively within low-income neighborhoods in Ontario, Canada.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used administrative data for Ontario, Canada, from April 1, 2002, to December 31, 2019. Included were all 414 337 hospital-based singleton live births and stillbirths occurring between 20 and 42 weeks' gestation, solely among women residing in an urban neighborhood of the lowest income quintile; all women were receiving universal health care insurance. Statistical analysis was performed from December 2021 to March 2022.

EXPOSURES

Nonrefugee immigrant status vs nonimmigrant status.

MAIN OUTCOMES AND MEASURES

The primary outcome, SMM-M, was a composite outcome of potentially life-threatening complications or mortality occurring within 42 days of the index birth hospitalization. A secondary outcome was SMM severity, approximated by the number of SMM indicators (0, 1, 2 or ≥3 indicators). Relative risks (RRs), absolute risk differences (ARDs), and odds ratios (ORs) were adjusted for maternal age and parity.

RESULTS

The cohort included 148 085 births to immigrant women (mean [SD] age at index birth, 30.6 [5.2] years) and 266 252 births to nonimmigrant women (mean [SD] age at index birth, 27.9 [5.9] years). Most immigrant women originated from South Asia (52 447 [35.4%]) and the East Asia and Pacific (35 280 [23.8%]) regions. The most frequent SMM indicators were postpartum hemorrhage with red blood cell transfusion, intensive care unit admission, and puerperal sepsis. The rate of SMM-M was lower among immigrant women (2459 of 148 085 [16.6 per 1000 births]) than nonimmigrant women (4563 of 266 252 [17.1 per 1000 births]), equivalent to an adjusted RR of 0.92 (95% CI, 0.88-0.97) and an adjusted ARD of -1.5 per 1000 births (95% CI, -2.3 to -0.7). Comparing immigrant vs nonimmigrant women, the adjusted OR of having 1 SMM indicator was 0.92 (95% CI, 0.87-0.98), the adjusted OR of having 2 indicators was 0.86 (95% CI, 0.76-0.98), and the adjusted OR of having 3 or more indicators was 1.02 (95% CI, 0.87-1.19).

CONCLUSIONS AND RELEVANCE

This study suggests that, among universally insured women residing in low-income urban areas, immigrant women have a slightly lower associated risk of SMM-M than their nonimmigrant counterparts. Efforts aimed at improving pregnancy care should focus on all women residing in low-income neighborhoods.

Racial and ethnic differences in severe maternal morbidity among singleton stillbirth deliveries

BACKGROUND

Despite growing evidence suggesting racial or ethnic disparities in the risk of severe maternal morbidity among live births, there is little research investigating potential differences in severe maternal morbidity risk among stillbirths across race and ethnicity.

OBJECTIVE

This study aimed to compare the risk of severe maternal morbidity by race and ethnicity among patients with singleton stillbirth pregnancies.

STUDY DESIGN

We used the California Linked Birth File database to perform a retrospective analysis of singleton stillbirth pregnancies delivered at 20 to 42 weeks' gestation between 2007 and 2011. The database contained information from fetal death certificates linked to maternal hospital discharge records. We defined severe maternal morbidity using the Centers for Disease Control and Prevention composite severe maternal morbidity indicator and compared rates of severe maternal morbidity across racial and ethnic groups. Multivariable regression analysis was used to examine how race and ethnicity were associated with severe maternal morbidity risk after accounting for the influence of patients' clinical risk factors, socioeconomic characteristics, and attributes of the delivery hospital.

RESULTS

Of the 9198 patients with singleton stillbirths, 533 (5.8%) experienced severe maternal morbidity. Non-Hispanic Black patients had a significantly higher risk of severe maternal morbidity (10.6% vs 5.2% in non-Hispanic White patients, 5.2% in Hispanic patients, and 5.1% in patients with other race or ethnicity; P<.001). The higher risk of severe maternal morbidity among non-Hispanic Black patients persisted even after adjusting for patients' clinical, socioeconomic, and hospital characteristics (adjusted odds ratio for non-Hispanic Black vs non-Hispanic White patients, 1.74; 95% confidence interval, 1.21-2.50). Further analysis separating blood-transfusion and nontransfusion severe maternal morbidity showed a higher risk of blood transfusion in non-Hispanic Black patients, which remained significant after adjusting for patients' clinical, socioeconomic, and hospital characteristics (adjusted odds ratio for non-Hispanic Black vs non-Hispanic White patients, 1.64; 95% confidence interval, 1.11-2.43). However, the higher risk of nontransfusion severe maternal morbidity in non-Hispanic Black patients was no longer significant after adjusting for patients' clinical risk factors (adjusted odds ratio for non-Hispanic Black vs non-Hispanic White patients, 1.38; 95% confidence interval, 0.83-2.30).

CONCLUSION

Severe maternal morbidity occurred in 5.8% of patients with a singleton stillbirth. Risk of severe maternal morbidity in stillbirth was higher in patients with non-Hispanic Black race, which was likely owing to a higher risk of hemorrhage, as evidenced by increased rate of blood transfusion.

Analysis of Residential Segregation and Racial and Ethnic Disparities in Severe Maternal Morbidity Before and During the COVID-19 Pandemic

IMPORTANCE

Persistent racial and ethnic disparities in severe maternal morbidity (SMM) in the US remain a public health concern. Structural racism leaves women of color in a disadvantaged situation especially during COVID-19, leading to disproportionate pandemic afflictions among racial and ethnic minority women.

OBJECTIVE

To examine racial and ethnic disparities in SMM rates before and during the COVID-19 pandemic and whether the disparities varied with level of Black residential segregation.

DESIGN, SETTING, AND PARTICIPANTS

A statewide population-based retrospective cohort study used birth certificates linked to all-payer childbirth claims data in South Carolina. Participants included women who gave birth between January 2018 and June 2021. Data were analyzed from December 2021 to February 2022.

EXPOSURES

Exposures were (1) period when women gave birth, either before the pandemic (January 2018 to February 2020) or during the pandemic (March 2020 to June 2021) and (2) Black-White residential segregation (isolation index), categorizing US Census tracts in a county as low (<40%), medium (40%-59%), and high (≥60%).

MAIN OUTCOMES AND MEASURES

SMM was identified using International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes developed by the US Centers for Disease Control and Prevention. Multilevel logistic regressions with an interrupted approach were used, adjusting for maternal-level and facility-level factors, accounting for residential county-level random effects.

RESULTS

Of 166 791 women, 95 098 (57.0%) lived in low-segregated counties (mean [SD] age, 28.1 [5.7] years; 5126 [5.4%] Hispanic; 20 523 [21.6%] non-Hispanic Black; 62 690 [65.9%] White), and 23 521 (14.1%) women (mean [SD] age, 28.1 [5.8] years; 782 [3.3%] Hispanic; 12 880 [54.8%] non-Hispanic Black; 7988 [34.0%] White) lived in high-segregated areas. Prepandemic SMM rates were decreasing, followed by monthly increasing trends after March 2020. On average, living in high-segregated communities was associated with higher odds of SMM (adjusted odds ratio [aOR], 1.61; 95% CI, 1.06-2.34). Black women regardless of residential segregation had higher odds of SMM than White women (aOR, 1.47; 95% CI, 1.11-1.96 for low-segregation; 2.12; 95% CI, 1.38-3.26 for high-segregation). Hispanic women living in low-segregated communities had lower odds of SMM (aOR, 0.48; 95% CI, 0.25-0.90) but those living in high-segregated communities had nearly twice the odds of SMM (aOR, 1.91; 95% CI, 1.07-4.17) as their White counterparts.

CONCLUSIONS AND RELEVANCE

Living in high-segregated Black communities in South Carolina was associated with racial and ethnic SMM disparities. During the COVID-19 pandemic, Black vs White disparities persisted with no signs of widening gaps, whereas Hispanic vs White disparities were exacerbated. Policy reforms on reducing residential segregation or combating the corresponding structural racism are warranted to help improve maternal health.

Double, Triple, and Quadruple Jeopardy: Entering Pregnancy With Two or More Multimorbid Diagnoses and Increased Risk of Severe Maternal Morbidity and Postpartum Readmission

INTRODUCTION

Multimorbidity, the presence of two or more chronic disease diagnoses, is associated with an increased risk of mortality and high health care costs in the general population and older adults. However, little evidence is available about the prevalence and impact of multimorbidity in obstetric populations. The goal of this analysis was to estimate the association between multimorbidity and severe maternal morbidity (SMM) and 90-day postpartum readmission in an obstetric cohort in Atlanta, Georgia.

STUDY DESIGN

We conducted a retrospective cohort study of livebirths and stillbirths at Grady Memorial Hospital, from October 2015 to April 2021. To determine preexisting chronic conditions, we linked information on births to inpatient diagnoses within the prior year. Multimorbidity was defined as the presence of two or more chronic disease diagnoses at birth or within the prior year. We conducted multivariable log binomial regression to estimate risk ratios and 95% confidence intervals for the crude and adjusted (for age, race/ethnicity, parity, and insurance) association between multimorbidity (two or more chronic conditions vs. zero or one) and SMM (at or within 42 days after birth) or 90-day postpartum readmission for any reason.

RESULTS

Of 14,225 included births, 10.1% were to patients with multimorbidity. Overall, SMM complicated 7.5% of births, and the 90-day readmission rate was 2.4%. Both SMM and readmission were more common among women with multimorbidity (SMM, 18.6% among women with multimorbidity compared with 6.3% without; 90-day readmission, 5.4% compared with 2.1%). Adjusting for potential confounders, multimorbidity was associated with increased risk of SMM (adjusted risk ratio, 2.9; 95% confidence interval, 2.5-3.0) and readmission (adjusted risk ratio, 2.2; 95% confidence interval, 1.7-2.9).

CONCLUSIONS

Individuals entering pregnancy with two or more chronic diseases were at an increased risk of SMM and postpartum readmission compared with individuals with one or zero chronic disease diagnoses.

Associations Between State-Level Severe Maternal Morbidity and Other Perinatal Indicators

This cross-sectional study examines state-level associations between severe maternal morbidity and other perinatal indicators, including prepregnancy hypertension, prepregnancy diabetes, prepregnancy obesity, low-risk cesarean delivery, preterm birth, and maternal and infant mortality.

The causal effect of delivery volume on severe maternal morbidity: an instrumental variable analysis in Sichuan, China

Objective

Findings regarding the association between delivery volume and maternal health outcomes are mixed, most of which explored their correlation. This study aims to demonstrate the causal effect of delivery volume on severe maternal morbidity (SMM) in China.

Methods

We analysed all women giving birth in the densely populated Sichuan province with 83 million residents in China, during the fourth quarters of each of 4 years (from 2016 to 2019). The routinely collected discharge data, the health institutional annual report data and road network data were used for analysis. The maternal health outcome was measured by SMM. Instrumental variable (IV) methods were applied for estimation, while the surrounding average number of delivery cases per institution was used as the instrument.

Results

The study included 4545 institution-years of data from 1456 distinct institutions with delivery services, reflecting 810 049 associated delivery cases. The average SMM rate was approximately 33.08 per 1000 deliveries during 2016 and 2019. More than 86% of delivery services were provided by a third of the institutions with the highest delivery volume (≥143 delivery cases quarterly). In contrast, less than 2% of delivery services were offered by a third of the institutions with the lowest delivery volume (<19 delivery cases quarterly). After adjusting the confounders in the IV-logistic models, the average marginal effect of per 1000 cases in delivery volume was −0.162 (95% CI −0.169 to –0.155), while the adjusted OR of delivery volume was 0.005 (95% CI 0.004 to 0.006).

Conclusion

Increased delivery volume has great potential to improve maternal health outcomes, while the centralisation of delivery services might facilitate maternal health promotion in China. Our study also provides implications for other developing countries confronted with similar challenges to China.

Severe Maternal Morbidity and Long-Term Risk of Cardiovascular Hospitalization

BACKGROUND

Severe maternal morbidity is rising, yet the association with cardiovascular disease is not clear. We examined the risk of cardiovascular hospitalization up to 3 decades after having a pregnancy complicated by severe maternal morbidity.

METHODS

We analyzed a longitudinal cohort of 1 336 846 women who were pregnant between 1989 and 2019 in Quebec, Canada. The main exposure measure was severe maternal morbidity in any pregnancy, including severe preeclampsia, acute renal failure, sepsis, and other life-threatening conditions. Using time-varying Cox regression models, we compared the adjusted risk of hospitalization for cardiovascular disease up to 3 decades after pregnancy for women with severe maternal morbidity relative to women without severe morbidity.

RESULTS

Five percent of women had severe maternal morbidity. Overall, there were 68 287 cardiovascular hospitalizations during 21 725 672 person-years of follow-up in the cohort. Compared with no morbidity, women with any severe morbidity had a greater risk of cardiovascular hospitalization (hazard ratio [HR], 1.77 [95% CI, 1.72-1.82]). The association was the greatest within the first year of delivery (HR, 4.42 [95% CI, 3.77-5.19]) but persisted beyond 15 years (HR, 1.44 [95% CI, 1.37-1.51]). Having a cardiac complication (HR, 5.37 [95% CI, 4.65-6.20]), cerebrovascular accident (HR, 3.82 [95% CI, 2.94-4.96]), or acute renal failure (HR, 2.60 [95% CI, 2.15-3.14]) during pregnancy was strongly associated with future cardiovascular hospitalization.

CONCLUSIONS

Women with severe maternal morbidity have a greater risk of cardiovascular disease after pregnancy, both in the short and long term. These women may benefit from active surveillance for cardiovascular disease.

A scoping review of maternal near miss assessment in Australia, New Zealand, South-East Asia and the South Pacific region: How, what, why and where to?

BACKGROUND

Severe maternal morbidity or maternal near miss (MNM) events can have significant consequences for individuals, their families and society and the study of these events may inform practices to reduce future adverse pregnancy outcomes.

AIMS

To review the scope of MNM studies undertaken in Australia, New Zealand, South-East Asia and the South Pacific region.

MATERIALS AND METHODS

A systematic search of four online databases (MEDLINE, EMBASE, SCOPUS and CINAHL) and the World Health Organization Library was conducted to identify all relevant studies published between 1 January 2011 and 31 December 2020. The studies were reviewed and included if they assessed MNM using a composite outcome or a predefined set of indicators.

RESULTS

The literature search yielded 143 articles of which 49 are included in this review. There were substantial differences in the monitoring approach to MNM in the Australasian region. Overall rates of MNM in the region ranged from two to 100/1000 births and the most common aetiologies identified were direct obstetric causes such as postpartum haemorrhage, pre-eclampsia and sepsis. Multidisciplinary review indicated a substantial number of MNM cases were preventable or amenable to improved management, mostly from a provider perspective.

CONCLUSIONS

Assessment of MNM is an important part of the evaluation of maternity care provision. Reaching a consensus on indicators and how best to collect information will allow a more discerning assessment of MNM including longer-term health outcomes, aspects of preventability and financial implications for health services.

Severe Maternal Morbidity in California Hospitals: Performance Based on a Validated Multivariable Prediction Model

BACKGROUND

Severe maternal morbidity (SMM) is under development as a quality indicator for maternal health care. The aim of this study is to evaluate California hospital performance based on a standardized SMM measure.

METHODS

California maternal hospital delivery discharge data from 2016 to 2017 were used to develop logistic regression models for SMM, adjusted for clinical risk factors at admission. Data from 2018 were used to test the models and evaluate hospital performance. SMM was defined per the Centers for Disease Control and Prevention, including (excluding) blood transfusion. Independent models were developed for each hospital type: community, teaching, integrated delivery system (IDS), and IDS teaching. Within each type, model-based expected SMM values and observed-to-expected (O/E) ratios were calculated for each hospital. For each hospital type, hospitals were ranked by O/E ratio, and over- and underperforming hospitals were identified using 95% confidence intervals.

RESULTS

Rates of SMM including (excluding) transfusion by hospital type were 1.7% (0.9%) for community, 2.7% (1.5%) for teaching, 2.3% (1.2%) for IDS, and 3.0% (1.6%) for IDS teaching hospitals. In higher-volume community hospitals (≥ 500 births/year), the proportion of underperformers including (excluding) transfusion was 20.7% (11.0%). Summing over all hospital types, 25.3% (14.9%) of hospitals were identified as underperformers in that they experienced significantly more SMM events than expected including (excluding) transfusion.

CONCLUSION

California hospital discharge data demonstrated significant hospital variation in standardized childbirth SMM. These data suggest that a standardized SMM measure may help guide and monitor statewide quality improvement efforts.