A Comprehensive Analysis of the Costs of Severe Maternal Morbidity

Individual and County-Level Factors Associated with Severe Maternal Morbidity at Delivery: An Investigation of a Privately Insured Population in the United States, 2008 to 2018

OBJECTIVE

 Few studies have explored the impact of county-level variables on severe maternal morbidity (SMM) subtypes. To address this gap, this study used a large commercial database to examine the associations between individual- and county-level factors and SMM.

STUDY DESIGN

 This retrospective cohort study used data from the Optum's deidentified Clinformatics Data Mart Database from 2008 to 2018. The primary outcomes of this study were any SMM, nontransfusion SMM, and nine specific SMM subtypes. Temporal trends in the prevalence of SMM and SMM subtypes were assessed using Joinpoint Regression. Multilevel logistic regression models were used to investigate the association of individual- and county-level factors with SMM.

RESULTS

 Between 2008 and 2018, there was not a significant change in the prevalence of any SMM (annual percent change [APC]: -0.9, 95% confidence interval [CI]: -2.2, 0.5). Significant increases in prevalence were identified for three SMM subtypes: other obstetric (OB) SMM (APC: 10.3, 95% CI: 0.1, 21.5) from 2013 to 2018, renal SMM (APC: 8.5, 95% CI: 5.5, 11.6) from 2008 to 2018, and sepsis (APC: 23.0, 95% CI: 6.5, 42.1) from 2014 to 2018. Multilevel logistic regression models revealed variability in individual and county risk factors across different SMM subtypes. Adolescent mothers (odds ratio [OR]: 2.10, 95% CI: 1.29, 3.40) and women in the 40 to 55 (OR: 1.67, 95% CI: 1.12, 2.51) age group were found to be at significant risk of other OB SMM and renal SMM, respectively. For every increase in rank within a county's socioeconomic social vulnerability index (SVI), the risk of respiratory SMM increased 2.8-fold, whereas an increase in rank in the racial/ethnic minority SVI was associated with a 1.6-fold elevated risk of blood transfusion.

CONCLUSION

 This study underscores the complex association between individual and county factors associated with SMM, emphasizing the need for multifaced approaches to improve maternal care.

KEY POINTS

· No increase in composite SMM rates from 2008 to 2018.. · Increases in obstetric SMM subtypes and sepsis.. · Risk factor profiles may differ across SMM subtypes.. · Key risk factors: age, comorbidities, prenatal care.. · County socioeconomic status associated with respiratory SMM risk..

Burden of Medical Costs Associated with Severe Maternal Morbidity in South Korea

BACKGROUND

Adverse maternal health outcomes lead to health loss and unnecessary medical costs. However, few have explored how severe maternal morbidity (SMM) affects medical costs separately from blood transfusion. Therefore, the aim of this study was to evaluate the delivery-related costs of healthcare services in patients with and without SMM as well as blood transfusion.

METHODS

This retrospective cohort study used the National Health Insurance Service (NHIS) Delivery Cohort database in South Korea. We included all delivering mothers in South Korea from 2016 to 2021, except those with incomplete data, totaling 1,517,773 participants. The measured outcomes included delivery-related medical costs associated with SMM. A generalized estimating equation model with a log link, gamma distribution, and robust standard errors was used to estimate the mean delivery-related medical costs of SMM.

RESULTS

SMM occurred in 2.2% of the cohort. The adjusted mean delivery-related medical costs were approximately 2.1- and 1.4-fold higher in cases with SMM without blood transfusion and only blood transfusion than in those without SMM, respectively ($2005, 95% CI: $1934-2078 and $1339, 95% CI: 1325-1354, respectively). The adjusted mean delivery-related medical costs were 1.5-fold higher in cases with SMM with blood transfusion than in those without SMM (SMM $1539, 95% CI: $1513-$1565).

CONCLUSIONS

Medical costs associated with delivery-related SMM with or without blood transfusion were significantly higher than those of normal deliveries, with excess costs varying according to existing healthcare policies. Policymakers should consider supporting programs to prevent high medical costs by improving maternal health.

Risk of Adverse Neonatal Events in Pregnancies Complicated by Severe Maternal Morbidity

OBJECTIVE

To investigate the risk of adverse neonatal events after a pregnancy complicated by severe maternal morbidity.

STUDY DESIGN

We analyzed a population-based cohort of deliveries in Quebec, Canada, between 2006 and 2021. The main exposure measure was severe maternal morbidity, comprising life-threatening conditions such as severe hemorrhage, cardiac complications, and eclampsia. The outcome included adverse neonatal events such as very preterm birth (gestational age <32 weeks), bronchopulmonary dysplasia, hypoxic ischemic encephalopathy, and neonatal death. Using log-binomial regression models, we estimated adjusted relative risks (RRs) and 95% confidence intervals (CIs) for the association between severe maternal morbidity and adverse neonatal events.

RESULTS

Among 1 199 112 deliveries, 29 992 (2.5%) were complicated by severe maternal morbidity and 83 367 (7.0%) had adverse neonatal events. Severe maternal morbidity was associated with 2.96 times the risk of adverse neonatal events compared with no morbidity (95% CI 2.90-3.03). Associations were greatest for mothers who required assisted ventilation (RR 5.86, 95% CI 5.34-6.44), experienced uterine rupture (RR 4.54, 95% CI 3.73-5.51), or had cardiac complications (RR 4.39, 95% CI 3.98-4.84). Severe maternal morbidity was associated with ≥3 times the risk of neonatal death and hypoxic-ischemic encephalopathy and ≥10 times the risk of very preterm birth and bronchopulmonary dysplasia.

CONCLUSIONS

Severe maternal morbidity is associated with an elevated risk of adverse neonatal events. Better prevention of severe maternal morbidity may help reduce burden of severe neonatal morbidity.

Racial and ethnic disparities in severe maternal morbidity from pregnancy through 1-year postpartum

BACKGROUND

Previous studies examining racial and ethnic disparities in severe maternal morbidity (SMM) have mainly focused on intrapartum hospitalization. There is limited information regarding the racial and ethnic distribution of SMM occurring in the antepartum and postpartum periods, including SMM occurring beyond the traditional 6 weeks postpartum period.

OBJECTIVE

To examine the racial and ethnic distribution of SMM during antepartum, intrapartum, and postpartum hospitalizations through 1-year postpartum, overall and stratified by maternal sociodemographic factors, and to estimate the percent increase in SMM by race and ethnicity and maternal sociodemographic factors within each racial and ethnic group after accounting for both antepartum and postpartum SMM through 1-year postpartum rather than just SMM occurring during the intrapartum hospitalization.

STUDY DESIGN

We conducted a retrospective cohort study using birth and fetal death certificate data linked to hospital discharge records from Michigan, Oregon, and South Carolina from 2008-2020. We examined the distribution of non-transfusion SMM and total SMM per 10,000 cases during antepartum, intrapartum, and postpartum hospitalizations through 365 days postpartum by race and ethnicity and by maternal education and insurance type within each racial and ethnic group. We subsequently examined "SMM cases added" by race and ethnicity and by maternal education and insurance type within each racial and ethnic group. The "SMM cases added" represent cases among unique individuals that are identified by considering the antepartum and postpartum periods but that would be missed if only the intrapartum hospitalization cases were included.

RESULTS

Among 2,584,206 birthing individuals, a total of 37,112 (1.4%) individuals experienced non-transfusion SMM and 64,661 (2.5%) experienced any SMM during antepartum, intrapartum, and/or postpartum hospitalization. Black individuals had the highest rate of antepartum, intrapartum, and postpartum non-transfusion and total SMM followed by American Indian individuals. Asian individuals had the lowest rate of non-transfusion and total SMM during antepartum and postpartum hospitalizations while White individuals had the lowest rate of non-transfusion and total SMM during the intrapartum hospitalization. Black individuals were 1.9 times more likely to experience non-transfusion SMM during the intrapartum hospitalization than White individuals, which increased to 2.8 times during the antepartum period and to 2.5 times during the postpartum period. Asian and Hispanic individuals were less likely to experience SMM in the postpartum period than White individuals. Including antepartum and postpartum hospitalizations resulted in disproportionately more cases among Black and American Indian individuals than among White, Hispanic, and Asian individuals. The additional cases were also more likely to occur among individuals with lower educational levels and individuals on government insurance.

CONCLUSION

Racial disparities in SMM are underreported in estimates that focus on the intrapartum hospitalization. Additionally, individuals with low socio-economic status bear the greatest burden of SMM occurring during the antepartum and postpartum periods. Approaches that focus on mitigating SMM during the intrapartum period only do not address the full spectrum of health disparities. El resumen está disponible en Español al final del artículo.

Severe maternal morbidity from pregnancy through 1 year postpartum

BACKGROUND

Few recent studies have examined the rate of severe maternal morbidity occurring during the antenatal and/or postpartum period to 42 days after delivery. However, little is known about the rate of severe maternal morbidity occurring beyond 42 days after delivery.

OBJECTIVE

This study aimed to examine the distribution of severe maternal morbidity and its indicators during antenatal, delivery, and postpartum hospitalizations to 365 days after delivery and to estimate the increase in severe maternal morbidity rate and its indicators after accounting for antenatal and postpartum severe maternal morbidity to 365 days after delivery.

STUDY DESIGN

This was a retrospective cohort study using birth and fetal death certificate data linked to hospital discharge records from Michigan, Oregon, and South Carolina from 2008 to 2020. This study examined the distribution of severe maternal morbidity, nontransfusion severe maternal morbidity, and severe maternal morbidity indicators during antenatal, delivery, and postpartum hospitalizations to 365 days after delivery. Subsequently, this study examined "severe maternal morbidity cases added," which represent cases among unique individuals that are included by considering the antenatal and postpartum periods but that would be missed if only the delivery hospitalization cases were included.

RESULTS

A total of 64,661 (2.5%) individuals experienced severe maternal morbidity, whereas 37,112 (1.4%) individuals experienced nontransfusion severe maternal morbidity during antenatal, delivery, and/or postpartum hospitalization. A total of 31% of severe maternal morbidity cases were added after accounting for severe maternal morbidity occurring during the antenatal or postpartum hospitalization to 365 days after delivery, whereas 49% of nontransfusion severe maternal morbidity cases were added after accounting for nontransfusion severe maternal morbidity occurring during the antenatal or postpartum periods. Severe maternal morbidity occurring between 43 and 365 days after delivery contributed to 12% of all severe maternal morbidity cases, whereas nontransfusion severe maternal morbidity occurring between 43 and 365 days after delivery contributed to 19% of all nontransfusion severe maternal morbidity cases.

CONCLUSION

Our study showed that a total of 31% of severe maternal morbidity and 49% of nontransfusion severe maternal morbidity cases were added after accounting for severe maternal morbidity occurring during the antenatal or postpartum hospitalization to 365 days after delivery. Our findings highlight the importance of expanding the severe maternal morbidity definition beyond the delivery hospitalization to better capture the full period of increased risk, identify contributing factors, and design strategies to mitigate this risk. Only then can we improve outcomes for mothers and subsequently the quality of life of their infants.

Postpartum healthcare expenditures for commercially insured deliveries with and without severe maternal morbidity

BACKGROUND

Although severe maternal morbidity is associated with adverse health outcomes in the year after delivery, patterns of healthcare use beyond the 6-week postpartum period have not been well documented.

OBJECTIVE

This study aimed to estimate healthcare utilization and expenditures for deliveries with and without severe maternal morbidity in the 12 months following delivery among commercially insured patients.

STUDY DESIGN

Using data from the 2016 to 2018 IBM Marketscan Commercial Claims and Encounters Research Databases, we identified deliveries to individuals 15 to 49 years of age who were continuously enrolled in noncapitated health plans for 12 months after delivery discharge. We used multivariable generalized linear models to estimate adjusted mean 12-month medical expenditures and 95% confidence intervals for deliveries with and without severe maternal morbidity, accounting for region, health plan type, delivery method, and obstetrical comorbidities. We estimated expenditures associated with inpatient admissions, nonemergency outpatient visits, outpatient emergency department visits, and outpatient pharmaceutical claims.

RESULTS

We identified 366,282 deliveries without severe maternal morbidity and 3976 deliveries (10.7 per 1000) with severe maternal morbidity. Adjusted mean total medical expenditures for deliveries with severe maternal morbidity were 43% higher in the 12 months after discharge than deliveries without severe maternal morbidity ($5320 vs $3041; difference $2278; 95% confidence interval, $1591-$2965). Adjusted mean expenditures for readmissions and nonemergency outpatient visits during the 12-month postpartum period were 61% and 39% higher, respectively, for deliveries with severe maternal morbidity compared with deliveries without severe maternal morbidity. Among deliveries with severe maternal morbidity, adjusted mean total costs were highest for patients living in the western region ($7831; 95% confidence interval, $5518-$10,144) and those having a primary cesarean ($7647; 95% confidence interval, $6323-$8970).

CONCLUSION

Severe maternal morbidity at delivery is associated with increased healthcare use and expenditures in the year after delivery. These estimates can inform planning of severe maternal morbidity prevention efforts.

Contraceptive counseling and choices in pregnancies with maternal cardiac disease

OBJECTIVE

Unplanned pregnancies in women with maternal cardiac disease (MCD) are associated with increased morbidity and mortality, but the majority of these individuals do not use highly reliable contraception on postpartum hospital discharge. Contraceptive counseling in this population outside of pregnancy is incomplete and counseling during pregnancy remains poorly characterized. Our objective was to evaluate the provision and quality of contraceptive counseling for individuals with MCD during pregnancy.

METHODS

All individuals with MCD who delivered between 2008 and 2021 at a tertiary care institution with a multidisciplinary cardio-obstetrics team were sent a 27-question survey. A subset of questions were derived from the validated Interpersonal Quality in Family Planning (IQFP) survey, which emphasizes interpersonal connection, adequate information, and decision support for the individual. Each participant received a $15 gift card for survey completion. We performed chart review for clinical and demographic details, including cardiac risk score.

RESULTS

Of 522 individuals to whom the survey was sent, 133 responded and met inclusion criteria. Overall, 67% discussed contraception with their general obstetrician, 36% with their maternal-fetal medicine (MFM) specialist, and 24% with their cardiologist. Compared to individuals with low cardiac risk scores, those with high cardiac risk scores had a nonsignificant trend toward being more likely to discuss contraception with a MFM provider (52% vs 33%, p = .08). 65% reported that their provider was 'excellent' or 'good' in all IQFP domains. Respondents valued providers who respected their autonomy and offered thorough counseling. Respondents disliked feeling pressured or uninformed about the safety of contraceptive options.

CONCLUSION

Most individuals with MCD reported excellent contraceptive counseling during pregnancy. Additional work is needed to understand barriers to and enablers for effective, patient-centered contraceptive counseling and use in this population.

Implementation research priorities for addressing the maternal health crisis in the USA: results from a modified Delphi study among researchers

BACKGROUND

Maternal health outcomes in the USA are far worse than in peer nations. Increasing implementation research in maternity care is critical to addressing quality gaps and unwarranted variations in care. Implementation research priorities have not yet been defined or well represented in the plans for maternal health research investments in the USA.

METHODS

This descriptive study used a modified Delphi method to solicit and rank research priorities at the intersection of implementation science and maternal health through two sequential web-based surveys. A purposeful, yet broad sample of researchers with relevant subject matter knowledge was identified through searches of published articles and grant databases. The surveys addressed five implementation research areas in maternal health: (1) practices to prioritize for broader implementation, (2) practices to prioritize for de-implementation, (3) research questions about implementation determinants, (4) research questions about implementation strategies, and (5) research questions about methods/measures.

RESULTS

Of 160 eligible researchers, 82 (51.2%) agreed to participate. Participants were predominantly female (90%) and White (75%). Sixty completed at least one of two surveys. The practices that participants prioritized for broader implementation were improved postpartum care, perinatal and postpartum mood disorder screening and management, and standardized management of hypertensive disorders of pregnancy. For de-implementation, practices believed to be most impactful if removed from or reduced in maternity care were cesarean delivery for low-risk patients and routine discontinuation of all psychiatric medications during pregnancy. The top methodological priorities of participants were improving the extent to which implementation science frameworks and measures address equity and developing approaches for involving patients in implementation research.

CONCLUSIONS

Through a web-based Delphi exercise, we identified implementation research priorities that researchers consider to have the greatest potential to improve the quality of maternity care in the USA. This study also demonstrates the feasibility of using modified Delphi approaches to engage researchers in setting implementation research priorities within a clinical area.

Racial/ethnic disparities in costs, length of stay, and severity of severe maternal morbidity

BACKGROUND

In contrast to other high-resource countries, the United States has experienced increases in the rates of severe maternal morbidity. In addition, the United States has pronounced racial and ethnic disparities in severe maternal morbidity, especially for non-Hispanic Black people, who have twice the rate as non-Hispanic White people.

OBJECTIVE

This study aimed to examine whether the racial and ethnic disparities in severe maternal morbidity extended beyond the rates of these complications to include disparities in maternal costs and lengths of stay, which could indicate differences in the case severity.

STUDY DESIGN

This study used California's linkage of birth certificates to inpatient maternal and infant discharge data for 2009 to 2011. Of the 1.5 million linked records, 250,000 were excluded because of incomplete data, for a final sample of 1,262,862. Cost-to-charge ratios were used to estimate costs from charges (including readmissions) after adjusting for inflation to December 2017. Mean diagnosis-related group-specific reimbursement was used to estimate physician payments. We used the Centers for Disease Control and Prevention definition of severe maternal morbidity, including readmissions up to 42 days after delivery. Adjusted Poisson regression models estimated the differential risk of severe maternal morbidity for each racial or ethnic group, compared with the non-Hispanic White group. Generalized linear models estimated the associations of race and ethnicity with costs and length of stay.

RESULTS

Asian or Pacific Islander, Non-Hispanic Black, Hispanic, and other race or ethnicity patients all had higher rates of severe maternal morbidity than non-Hispanic White patients. The largest disparity was between non-Hispanic White and non-Hispanic Black patients, with unadjusted overall rates of severe maternal morbidity of 1.34% and 2.62%, respectively (adjusted risk ratio, 1.61; P<.001). Among patients with severe maternal morbidity, the adjusted regression estimates showed that non-Hispanic Black patients had 23% (P<.001) higher costs (marginal effect of $5023) and 24% (P<.001) longer hospital stays (marginal effect of 1.4 days) than non-Hispanic White patients. These effects changed when cases, such as cases where a blood transfusion was the only indication of severe maternal morbidity, were excluded, with 29% higher costs (P<.001) and 15% longer length of stay (P<.001). For other racial and ethnic groups, the increases in costs and length of stay were smaller than those observed for non-Hispanic Black patients, and many were not significantly different from non-Hispanic White patients. Hispanic patients had higher rates of severe maternal morbidity than non-Hispanic White patients; however, Hispanic patients had significantly lower costs and length of stay than non-Hispanic White patients.

CONCLUSION

There were racial and ethnic differences in the costs and length of stay among patients with severe maternal morbidity across the groupings that we examined. The differences were especially large for non-Hispanic Black patients compared with non-Hispanic White patients. Non-Hispanic Black patients experienced twice the rate of severe maternal morbidity; in addition, the higher relative costs and longer lengths of stay for non-Hispanic Black patients with severe maternal morbidity support greater case severity in that population. These findings suggest that efforts to address racial and ethnic inequities in maternal health need to consider differences in case severity in addition to the differences in the rates of severe maternal morbidity and that these differences in case severity merit additional investigation.

Severe Maternal Morbidity and Postpartum Readmission Through 1 Year

OBJECTIVE

To conduct a cohort study to estimate risk for readmission through 1 year postpartum and the most common readmission diagnoses for individuals with and without severe maternal morbidity (SMM) at delivery.

METHODS

Using national health care claims data from IBM MarketScan Commercial Research Databases (now known as Merative), we identified all delivery hospitalizations for continuously enrolled individuals 15-49 years of age that occurred between January 1, 2016, and December 31, 2018. Severe maternal morbidity at delivery was identified using diagnosis and procedure codes. Individuals were followed for 365 days after delivery discharge, and cumulative readmission rates were calculated for up to 42 days, up to 90 days, up to 180 days, and up to 365 days. We used multivariable generalized linear models to estimate adjusted relative risks (aRR), adjusted risk differences, and 95% CIs for the association between readmission and SMM at each of the timepoints.

RESULTS

The study population included 459,872 deliveries; 5,146 (1.1%) individuals had SMM during the delivery hospitalization, and 11,603 (2.5%) were readmitted within 365 days. The cumulative incidence of readmission was higher in individuals with SMM than those without at all timepoints (within 42 days: 3.5% vs 1.2%, aRR 1.44, 95% CI 1.23-1.68; within 90 days: 4.1% vs 1.4%, aRR 1.46, 95% CI 1.26-1.69); within 180 days: 5.0% vs 1.8%, aRR 1.48, 95% CI 1.30-1.69; within 365 days: 6.4% vs 2.5%, aRR 1.44, 95% CI 1.28-1.61). Sepsis and hypertensive disorders were the most common reason for readmission within 42 and 365 days for individuals with SMM (35.2% and 25.8%, respectively).

CONCLUSION

Severe maternal morbidity at delivery was associated with increased risk for readmission throughout the year after delivery, a finding that underscores the need for heightened awareness of risk for complications beyond the traditional 6-week postpartum period.

State Perinatal Quality Collaborative for Reducing Severe Maternal Morbidity From Hemorrhage: A Cost-Effectiveness Analysis

OBJECTIVE

To evaluate the cost effectiveness of California's statewide perinatal quality collaborative for reducing severe maternal morbidity (SMM) from hemorrhage.

METHODS

A decision-analytic model using open source software (Amua 0.30) compared outcomes and costs within a simulated cohort of 480,000 births to assess the annual effect in the state of California. Our model captures both the short-term costs and outcomes that surround labor and delivery and long-term effects over a person's remaining lifetime. Previous studies that evaluated the effectiveness of the CMQCC's (California Maternal Quality Care Collaborative) statewide perinatal quality collaborative initiative-reduction of hemorrhage-related SMM by increasing recognition, measurement, and timely response to postpartum hemorrhage-provided estimates of intervention effectiveness. Primary cost data received from select hospitals within the study allowed for the estimation of collaborative costs, with all other model inputs derived from literature. Costs were inflated to 2021 dollars with a cost-effectiveness threshold of $100,000 per quality-adjusted life-year (QALY) gained. Various sensitivity analyses were performed including one-way, scenario-based, and probabilistic sensitivity (Monte Carlo) analysis.

RESULTS

The collaborative was cost effective, exhibiting strong dominance when compared with the baseline or standard of care. In a theoretical cohort of 480,000 births, collaborative implementation added 182 QALYs (0.000379/birth) by averting 913 cases of SMM, 28 emergency hysterectomies, and one maternal mortality. Additionally, it saved $9 million ($17.78/birth) due to averted SMM costs. Although sensitivity analyses across parameter uncertainty ranges provided cases where the intervention was not cost saving, it remained cost effective throughout all analyses. Additionally, scenario-based sensitivity analysis found the intervention cost effective regardless of birth volume and implementation costs.

CONCLUSION

California's statewide perinatal quality collaborative initiative to reduce SMM from hemorrhage was cost effective-representing an inexpensive quality-improvement initiative that reduces the incidence of maternal morbidity and mortality, and potentially provides cost savings to the majority of birthing hospitals.

Societal cost of nine selected maternal morbidities in the United States

OBJECTIVE

To estimate the cost of maternal morbidity for all 2019 pregnancies and births in the United States.

METHODS

Using data from 2010 to 2020, we developed a cost analysis model that calculated the excess cases of outcomes attributed to nine maternal morbidity conditions with evidence of outcomes in the literature. We then modeled the associated medical and nonmedical costs of each outcome incurred by birthing people and their children in 2019, projected through five years postpartum.

RESULTS

We estimated that the total cost of nine maternal morbidity conditions for all pregnancies and births in 2019 was $32.3 billion from conception to five years postpartum, amounting to $8,624 in societal costs per birthing person.

CONCLUSION

We found only nine maternal morbidity conditions with sufficient supporting evidence of linkages to outcomes and costs. The lack of comprehensive data for other conditions suggests that maternal morbidity exacts a higher toll on society than we found.

POLICY IMPLICATIONS

Although this study likely provides lower bound cost estimates, it establishes the substantial adverse societal impact of maternal morbidity and suggests further opportunities to invest in maternal health.

The effect of severe maternal morbidity on infant costs and lengths of stay

OBJECTIVE

To examine the association between severe maternal morbidity (SMM) and infant health using the additional infant costs and length of stay (LOS) as markers of added clinical complexity.

STUDY DESIGN

Secondary data analysis using California linked birth certificate-patient discharge data for 2009-2011 (N = 1,260,457). Regression models were used to estimate the association between SMM and infant costs and LOS.

RESULTS

The 16,687 SMM-exposed infants experienced a $6550 (33%) increase in costs and a 0.7 (18%) day increase in LOS. Preterm infants had ($11,258 (18%) added costs and 1.3 days (8.1%) longer LOS) than term infants ($2539 (38%) added costs and 0.5 days (22%) longer LOS).

CONCLUSIONS

SMM was associated with increased infant costs and LOS, suggesting that SMM may have adverse health effects for infants, including term infants. The relatively larger effect on costs indicates an increase in treatment intensity (clinical severity) greater than additional LOS.