Maternal age-specific drivers of severe maternal morbidity

Trends and Disparities in Severe Maternal Morbidity Indicator Categories during Childbirth Hospitalization in California from 1997 to 2017

OBJECTIVE

Severe maternal morbidity (SMM) is increasing and characterized by substantial racial and ethnic disparities. Analyzing trends and disparities across time by etiologic or organ system groups instead of an aggregated index may inform specific, actionable pathways to equitable care. We explored trends and racial and ethnic disparities in seven SMM categories at childbirth hospitalization.

STUDY DESIGN

We analyzed California birth cohort data on all live and stillbirths ≥ 20 weeks' gestation from 1997 to 2017 (n = 10,580,096) using the Centers for Disease Control and Prevention's SMM index. Cases were categorized into seven nonmutually exclusive indicator categories (cardiac, renal, respiratory, hemorrhage, sepsis, other obstetric, and other medical SMM). We compared prevalence and trends in SMM indicator categories overall and by racial and ethnic group using logistic and linear regression.

RESULTS

SMM occurred in 1.16% of births and nontransfusion SMM in 0.54%. Hemorrhage SMM occurred most frequently (27 per 10,000 births), followed by other obstetric (11), respiratory (7), and sepsis, cardiac, and renal SMM (5). Hemorrhage, renal, respiratory, and sepsis SMM increased over time for all racial and ethnic groups. The largest disparities were for Black individuals, including over 3-fold increased odds of other medical SMM. Renal and sepsis morbidity had the largest relative increases over time (717 and 544%). Sepsis and hemorrhage SMM had the largest absolute changes over time (17 per 10,000 increase). Disparities increased over time for respiratory SMM among Black, U.S.-born Hispanic, and non-U.S.-born Hispanic individuals and for sepsis SMM among Asian or Pacific Islander individuals. Disparities decreased over time for sepsis SMM among Black individuals yet remained substantial.

CONCLUSION

Our research further supports the critical need to address SMM and disparities as a significant public health priority in the United States and suggests that examining SMM subgroups may reveal helpful nuance for understanding trends, disparities, and potential needs for intervention.

KEY POINTS

· By SMM subgroup, trends and racial and ethnic disparities varied yet Black individuals consistently had highest rates.. · Hemorrhage, renal, respiratory, and sepsis SMM significantly increased over time.. · Disparities increased for respiratory SMM among Black, U.S.-born Hispanic and non-U.S.-born Hispanic individuals and for sepsis SMM among Asian or Pacific Islander individuals..

Risk Factors for Severe Maternal Morbidity Among Women Enrolled in Mississippi Medicaid

Importance

Mississippi has one of the highest rates of severe maternal morbidity (SMM) in the US, and SMMs have been reported to be more frequent among Medicaid-insured women. A substantial proportion of pregnant women in Mississippi are covered by Medicaid; hence, there is a need to identify potential risk factors for SMM in this population.

Objective

To examine the associations of health care access and clinical and sociodemographic characteristics with SMM events among Mississippi Medicaid-enrolled women who had a live birth.

Design, Setting, and Participants

A nested case-control study was conducted using 2018 to 2021 Mississippi Medicaid administrative claims database. The study included Medicaid beneficiaries aged 12 to 55 years who had a live birth and were continuously enrolled throughout their pregnancy period and 12 months after delivery. Individuals in the case group had SMM events and were matched to controls on their delivery date using incidence density sampling. Data analysis was performed from June to September 2022.

Exposure

Risk factors examined in the study included sociodemographic factors (age and race), health care access (distance from delivery center, social vulnerability index, and level of maternity care), and clinical factors (maternal comorbidity index, first-trimester pregnancy-related visits, and postpartum care).

Main Outcomes and Measures

The main outcome of the study was an SMM event. Adjusted odds ratio (aORs) and 95% CIs were calculated using conditional logistic regression.

Results

Among 13 485 Mississippi Medicaid-enrolled women (mean [SD] age, 25.0 [5.6] years; 8601 [63.8%] Black; 4419 [32.8%] White; 465 [3.4%] other race [American Indian, Asian, Hispanic, multiracial, and unknown]) who had a live birth, 410 (3.0%) were in the case group (mean [SD] age, 26.8 [6.4] years; 289 [70.5%] Black; 112 [27.3%] White; 9 [2.2%] other race) and 820 were in the matched control group (mean [SD] age, 24.9 [5.7] years; 518 [63.2%] Black; 282 [34.4%] White; 20 [2.4%] other race). Black individuals (aOR, 1.44; 95% CI, 1.08-1.93) and those with higher maternal comorbidity index (aOR, 1.27; 95% CI, 1.16-1.40) had higher odds of experiencing SMM compared with White individuals and those with lower maternal comorbidity index, respectively. Likewise, an increase of 100 miles (160 km) in distance between beneficiaries' residence to the delivery center was associated with higher odds of experiencing SMM (aOR, 1.14; 95% CI, 1.07-1.20).

Conclusions and Relevance

The study findings hold substantial implications for identifying high-risk individuals within Medicaid programs and call for the development of targeted multicomponent, multilevel interventions for improving maternal health outcomes in this highly vulnerable population.

Analysis of Heat Exposure During Pregnancy and Severe Maternal Morbidity

Importance

The rate of severe maternal morbidity (SMM) is continuously increasing in the US. Evidence regarding the associations of climate-related exposure, such as environmental heat, with SMM is lacking.

Objective

To examine associations between long- and short-term maternal heat exposure and SMM.

Design, Setting, and Participants

This retrospective population-based epidemiological cohort study took place at a large integrated health care organization, Kaiser Permanente Southern California, between January 1, 2008, and December 31, 2018. Data were analyzed from February to April 2023. Singleton pregnancies with data on SMM diagnosis status were included.

Exposures

Moderate, high, and extreme heat days, defined as daily maximum temperatures exceeding the 75th, 90th, and 95th percentiles of the time series data from May through September 2007 to 2018 in Southern California, respectively. Long-term exposures were measured by the proportions of different heat days during pregnancy and by trimester. Short-term exposures were represented by binary variables of heatwaves with 9 different definitions (combining percentile thresholds with 3 durations; ie, ≥2, ≥3, and ≥4 consecutive days) during the last gestational week.

Main Outcomes and Measures

The primary outcome was SMM during delivery hospitalization, measured by 20 subconditions excluding blood transfusion. Discrete-time logistic regression was used to estimate associations with long- and short-term heat exposure. Effect modification by maternal characteristics and green space exposure was examined using interaction terms.

Results

There were 3446 SMM cases (0.9%) among 403 602 pregnancies (mean [SD] age, 30.3 [5.7] years). Significant associations were observed with long-term heat exposure during pregnancy and during the third trimester. High exposure (≥80th percentile of the proportions) to extreme heat days during pregnancy and during the third trimester were associated with a 27% (95% CI, 17%-37%; P < .001) and 28% (95% CI, 17%-41%; P < .001) increase in risk of SMM, respectively. Elevated SMM risks were significantly associated with short-term heatwave exposure under all heatwave definitions. The magnitude of associations generally increased from the least severe (HWD1: daily maximum temperature >75th percentile lasting for ≥2 days; odds ratio [OR], 1.32; 95% CI, 1.17-1.48; P < .001) to the most severe heatwave exposure (HWD9: daily maximum temperature >95th percentile lasting for ≥4 days; OR, 2.39; 95% CI, 1.62-3.54; P < .001). Greater associations were observed among mothers with lower educational attainment (OR for high exposure to extreme heat days during pregnancy, 1.43; 95% CI, 1.26-1.63; P < .001) or whose pregnancies started in the cold season (November through April; OR, 1.37; 95% CI, 1.24-1.53; P < .001).

Conclusions and Relevance

In this retrospective cohort study, long- and short-term heat exposure during pregnancy was associated with higher risk of SMM. These results might have important implications for SMM prevention, particularly in a changing climate.

Quantification of placental extracellular vesicles in different pregnancy status via single particle analysis method

BACKGROUND

The nano-sized, lipid bilayer-delimited placental extracellular vesicles (PEVs) released by the placenta are now regarded as important mediators involved in various physiological and pathological processes of pregnant women. The number and contents of PEVs are significantly altered in preeclampsia and are considered as potential biomarkers. However, the distribution pattern of PEVs in the maternal circulation in different pregnancy status is still unclear for the limitation of the traditional method with low sensitivity.

METHODS

In this work, we recruited 561 pregnant women with different pregnancy status and investigated the distribution pattern of PEVs in the maternal circulation based on a single extracellular vesicle analysis method and placental alkaline phosphatase (PLAP), a placenta-specific marker.

RESULTS

The concentration of PEVs in pregnant women increased with the progression of gestational age, while the ratio of PEVs decreased to about 10% in the third trimester. Surprisingly, the PLAP⁺ EVs also presented in the plasma of non-pregnant women and normal male about 5%. The change in the ratio of PEVs can reflect the pregnancy status and also had a better diagnostic value in severe preeclampsia (AUC = 0.7811).

CONCLUSIONS

Our study not only reveals the distribution pattern of PEVs, but also identifies the diagnostic potential of PEVs as biomarkers.

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.