https://orcid.org/0000-0002-0355-1014
Abstract
Background
Prehospital obstetric events, including out-of-hospital deliveries and their complications, are a rare but high-risk event encountered by emergency medical services (EMS). Understanding the epidemiology of these encounters would help identify strategies to improve prehospital obstetric care. Our objective was to determine the characteristics of out-of-hospital deliveries and high-risk complications treated by EMS clinicians in the U.S.
Methods
We conducted a cross-sectional analysis of EMS patient care records in the 2018 and 2019 National EMS Information System Public Release Version 3.4 datasets. We included EMS activations after a 9-1-1 scene response for patients aged 12–50 years with evidence of an out-of-hospital delivery or delivery complication, or where the patient was a newborn aged 0-<6 h. We examined patient, community, emergency response, and clinical characteristics using descriptive statistics.
Results
Of the 56,735,977 EMS activations included in the 2018 and 2019 datasets, there were 8,614 out-of-hospital deliveries, 1,712 delivery complications, and 5,749 records for newborns. Most maternal (76%) out-of-hospital deliveries involved patients between the ages of 20–34 years, occurred on a weekday (73%), were treated by an advanced life support crew (85%), and occurred in a home or residence (73%). EMS-assisted field delivery was documented in 3,515 (34%) of all maternal activations but only 2% of activations with a delivery complication. Few patients received an EMS-administered medication (e.g., 0.4% received oxytocin). Supplemental oxygen was administered in 870 (15%) of newborn activations. Activations from counties with the most racial/ethnic diversity were more often treated by a BLS-level unit (16% vs. 12%, p < 0.001), and activations from rural areas had significantly longer transport times (19.7 min [IQR 8.7, 32.8] vs. urban, 13.1 min [IQR 8.7, 19.7], p < 0.001).
Conclusion
In this large, national repository of EMS patient care records from across the U.S., most activations for out-of-hospital delivery, delivery complication, or a newborn included only routine EMS care. There were potential disparities in level of care, clinical care provided, and measures of access to definitive care based on maternal and community factors. We also identified gaps in current practice, such as for postpartum hemorrhage, that could be addressed with changes in EMS clinical protocols and regulations.
Introduction
In the United States, childbirth typically occurs in medical settings, such as a hospital or birthing center or as a planned home birth. However, in certain circumstances, pregnant patients may unexpectedly give birth outside of these controlled settings, leading to an out-of-hospital delivery. Out-of-hospital childbirth attended by emergency medical services (EMS) is a rare, potentially high-risk, and usually unplanned event. Less than 1% of all EMS emergency activations in the U.S. are for an obstetric complaint, including out-of-hospital delivery (Citation1–3). While the most common obstetric-related EMS presentation is for the laboring patient (Citation1), thousands of mothers give birth with EMS assistance or prior to EMS arrival every year. Most prehospital obstetric conditions likely require only routine EMS assessment and care, but approximately one-third of these events include a potentially high-acuity patient or complication that may require extensive prehospital care (Citation1, Citation4, Citation5). Furthermore, unplanned out-of-hospital deliveries are associated with complications such as postpartum hemorrhage, need for intensive care of the newborn, and even maternal or neonatal death (Citation6–11). This unique scenario places both patients in a situation where immediate and appropriate prehospital care provided by EMS are paramount for good outcome.
Maternal mortality continues to increase in the U.S., with a mortality rate of 32.9 deaths per 100,000 live births in 2021 (Citation12). Efforts to reduce maternal and neonatal morbidity and mortality have focused on quality improvement and training for hospital-based healthcare providers but not for the prehospital providers who may initially encounter, triage, and treat these patients (Citation13, Citation14). EMS clinicians receive limited training and education on the prehospital management of the critically ill pregnant patient (Citation15, Citation16), thus many report feeling unprepared to manage their care (Citation17). There are several recent guidelines for prehospital obstetric care covering maternal resuscitation during cardiac arrest and prehospital trauma care for the pregnant patient (Citation18–20). However, most courses and curriculums covering obstetric care topics are not necessarily relevant for the prehospital setting (Citation21, Citation22). EMS clinical protocols also may not reflect current best practices for obstetric care and may not always address the most common complications encountered.
As access to obstetric care declines in rural areas (Citation23), EMS clinicians may be called to handle a higher volume of obstetric conditions. High quality care provided by EMS in these situations may help prevent additional morbidity and mortality for this particularly high-risk population. Understanding the epidemiology of out-of-hospital deliveries, and its complications, would help inform future research and guideline development to improve the quality of prehospital obstetric care. Thus, our objective was to determine the patient, community, emergency response, and clinical characteristics of out-of-hospital deliveries and high-risk complications treated by EMS clinicians in the U.S.
Methods
Study Design, Setting, & Data Sources
This was a cross-sectional analysis of EMS patient care records in the 2018 and 2019 National EMS Information System (NEMSIS) Public Release Research Datasets, Version 3.4 (Citation24). NEMSIS is a collaboration with the National Highway Traffic Safety Administration’s Office of EMS and the University of Utah. NEMSIS is the largest repository of EMS patient care records in the U.S., containing over 56 million EMS activations (i.e., calls for service) during the study period from over 12,000 EMS agencies in 50 states and territories (Citation24). EMS agencies and states submit a standardized set of national data elements for each record, which are then de-identified and made publicly available for research.
We further included county-level community characteristics data, which were deterministically merged into the NEMSIS dataset by the NEMSIS Technical Assistance Center staff and then de-identified. We obtained the overall and “minority status & language” theme rankings of the 2018 CDC/ATSDR Social Vulnerability Index (SVI) at the county level. The SVI uses 15 variables from the U.S. Census’ American Community Survey (ACS) 5-year estimates (2014–2018), organized into 4 themes (socioeconomic; household composition & disability, minority status & language; and housing type & transportation), to rank counties by vulnerability within each theme and overall. From the 2018 ACS 5-year estimates, we also obtained the percentage of the population in each county reporting their race as Black. From the 2018 Area Health Resource File from the U.S. Health Resources & Services Administration, we obtained the county-level preterm birth rate and presence of an obstetric-capable hospital. Due to data restrictions, only a limited number of variables could be included.
The Mass General Brigham institutional review board reviewed this study and deemed it non-human subjects research due to the de-identified nature of the publicly available data.
Selection of Participants
For this study, we used patient care reports from EMS activations for emergency or 9-1-1 scene responses with patient involvement from January 1, 2018 to December 31, 2019. We included activations for patients aged 12–50 years with documented symptoms, impressions, or procedures indicating out-of-hospital delivery or delivery complication. We also included activations with patients aged zero to <6 h, regardless of complaint or impression, to capture the records of newborns after delivery. We identified an out-of-hospital delivery or delivery complication based on one or more of the following: primary and secondary symptoms documented by the treating EMS clinician; the EMS clinician’s primary and secondary impressions (i.e., field diagnosis) of the patient’s complaint; and procedures performed by EMS (Supplemental Table S1). Patient symptoms and impressions were based on a subset of International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes (Citation25), for which we selected codes that referred to delivery and delivery complications, including prolapsed or nuchal cord, abnormal presentation (e.g., breech, limb presentation), shoulder dystocia, and hemorrhage. Procedures were based on the Standardized Nomenclature of Medicine Clinical Terms (Citation26), for which we selected 17 procedures relating to out-of-hospital delivery (Supplemental Table S1).
Because only gender, rather than biological sex, was recorded, we did not place restriction on the documented gender of patients. We excluded any activation that was a non-emergency response (e.g., interfacility or non-emergency medical transport); if the record had no indication of an out-of-hospital delivery; where the patient was not treated and transported by the same EMS unit (to prevent counting an event more than once); or if the patient was outside of the specified age range, including if age was missing.
Measures
We examined patient, incident, clinical, and community characteristics of out-of-hospital deliveries, delivery complications, and newborns. Patient and incident characteristics included maternal age, day of week, time of day, level of EMS response, location where the patient was found, and EMS time intervals. Clinical characteristics included primary symptom and impression, indication of substance use or trauma, procedures performed by EMS, and medications administered by EMS. Patient race/ethnicity was not examined due to the extent of missingness in this variable in EMS records. Instead, community-level measures of diversity were used. Community characteristics included urbanicity, quartile of minority status & language theme ranking of the SVI for the county, presence of an obstetric-capable hospital in the county, and whether the county was in the highest quartile of overall SVI ranking, percentage of the population reporting their race as Black, and preterm birth rate.
Data Analysis
Descriptive statistics were calculated to describe the characteristics of each maternal EMS activation, stratified by out-of-hospital deliveries and delivery complications. We examined differences in maternal characteristics by age, minority status & language SVI ranking, urbanicity, time of day, and day of week using chi-square, Wilcoxon rank sum, and Kruskal-Wallis tests as appropriate. Finally, we calculated descriptive statistics in the newborn records. Missing data were handled by available case analysis.
Results
Of the 56,735,977 EMS activations included in the 2018 and 2019 datasets, 15,992 activations met inclusion criteria (). A total of 10,243 (64%) were maternal records, with 8,614 (84%) out-of-hospital deliveries and 1,712 (17%) having evidence of a delivery complication. A total of 83 (1%) had evidence of both an out-of-hospital delivery and delivery complication. Of the complications, there were 1,608 (94%) activations for hemorrhage, 95 (6%) for abnormal presentation, 4 (0.2%) for shoulder dystocia, and 6 (0.4%) for a nuchal cord. There were 5,749 additional total records with a patient aged <6 h.
Figure 1. Flow chart.
The median age of patients in the maternal activations was 28 years (interquartile range [IQR] 23, 32; ), and 7,761 (76%) were between the ages of 20–34 years. A slightly higher proportion of maternal activations with a delivery complication were among patients aged 35–50 years (21% vs. 16% overall). Most maternal activations occurred on a weekday (73%), were treated by an ALS-level unit (85%), and occurred in a home or residence (73%).
Table 1. Patient and incident of EMS activations.
The most common primary symptom and impression for the maternal records overall was “pregnancy, childbirth, and puerperium” (), though more than half of delivery complications and newborn activations were classified as “symptoms and abnormal clinical/laboratory findings.” There were few activations that had documentation of alcohol or drug use (2% for maternal, 4% for newborn), and 10% of newborn activations had documentation of a traumatic injury. Vascular access was obtained in 43% of all maternal activations and 11% of newborn activations, though very few patients received intravenous fluids or medications. Basic and advanced airway management was provided in 459 (8%) and 52 (1%), respectively, of newborn activations. EMS-assisted field delivery was documented in 3,515 (34%) of all maternal activations but only 2% of activations with a delivery complication, indicating many patients had likely delivered prior to EMS arrival. Few patients received an EMS-administered medication, including 41 (0.4%) with documentation of oxytocin. All delivery complications that had documentation of oxytocin (n = 20, 1%) also had evidence of hemorrhage. Supplemental oxygen was administered in 870 (15%) of newborn activations. There were no activations with documentation of fundal massage or administration of blood products.
Table 2. Clinical characteristics of EMS activations.
Examining community characteristics, most patients (87%) came from an urban area (). About one-third of patients came from a county in the top quartile of social vulnerability (i.e., most vulnerable), though fewer patients with a delivery complication came from the most vulnerable communities. Similarly, 65% of all maternal and 70% of newborn activations were from counties in the highest quartile of minority status and language theme of the SVI. Overall, most counties had at least one obstetric-capable hospital in the county.
Table 3. Community characteristics of EMS activations.
When stratified by maternal age (Supplemental Table S2), median scene time was higher among those in the oldest age group (35–50 years: 13.1 min [IQR 8.7, 19.7]; 12–19 and 20–34 years: 10.9 min [IQR 6.6, 17.5]; p < 0.001). The oldest age group was also more likely to have an indication of alcohol or drug use documented (3% vs. 1% and 2% for 12–19 and 20–34, respectively, p = 0.002). The youngest age group more commonly came from a county in the top quartile of social vulnerability (41% vs. 30% of 20–34-year-olds and 24% of 35–50-year-olds, p < 0.001) and top quartile of preterm birth rate (19% vs. 14% of 20–34-year-olds and 19% of 35–50-year-olds, p < 0.001).
As expected, based on anecdotal evidence, activations from the top quartile of minority status and language component of the SVI were more often treated by a BLS-level unit (16% vs. 12%, p < 0.001; Supplemental Table S3), found at home (74% vs. 69%, p < 0.001), and from an urban area (95% vs. 71%, p < 0.001). A lower proportion had vascular access documented (41% vs. 48%, p < 0.001) or administration of medications (e.g., oxytocin: 0.2% vs. 1%, p < 0.001). There were also significant differences in all community characteristics, such as a higher proportion with high social vulnerability and more frequent presence of an obstetric-capable hospital in the county (90% vs. 72%, p < 0.001). When stratified by urbanicity (Supplemental Table S4), activations from rural areas had significantly longer total prehospital times, driven by longer response and transport time (e.g., median transport time in rural areas of 19.7 min, IQR 8.7, 32.8 vs. 13.1 min, IQR 8.7, 19.7, p < 0.001). Activations from rural areas were also more likely to be in the top quartile of social vulnerability (41% vs. 29%, p < 0.001) and less likely to have an obstetric-capable hospital in the county (48% vs. 89%, p < 0.001). These findings mirror common beliefs.
Finally, when stratified by time of day (Supplemental Table S5) and day of week (Supplemental Table S6), there were significant differences in where patients were found, with more found in a home or residence at night (76% vs. day, 69%, p < 0.001) and on the weekend (74% vs. weekday, 72%, p = 0.03). Activations occurring at night had a slightly lower proportion with vascular access documented (41% vs. 46%, p < 0.001). Activations occurring on the weekend had slightly higher proportion with an indication of alcohol or drug use (3% vs 2%, p = 0.03).
Discussion
In this large, national repository of EMS patient care records from across the U.S., we identified out-of-hospital deliveries treated by EMS, activations with a delivery complication, and activations where the patient was likely a newborn being transported shortly after birth. Most activations included only routine care provided by EMS, with few having documentation of an advanced airway placement or intravenous medication administration. Of the complications examined, hemorrhage was the most prevalent; however, only 1% received oxytocin administered by EMS and even fewer received tranexamic acid (TXA). Furthermore, there were significant associations found between maternal and community characteristics that demonstrate potential disparities in care that require more in-depth investigation.
Disparities in out-of-hospital deliveries highlight potential inequalities in access to timely and appropriate obstetric care. Reasons for unplanned out-of-hospital deliveries could not be investigated in this dataset but are often associated with a lack of prenatal care, lack of geographic access to a hospital with obstetric services, socioeconomic disadvantage, and maternal characteristics such as multiparity (Citation9, Citation27, Citation28). We found that activations from counties with the highest levels of diversity or in rural areas had a lower proportion of patients treated by advanced life support EMS crews, which in turn was reflected by lower rates of interventions that can only be provided by a paramedic, such as intravenous medications. This demonstrates disparities in the systems of care in many communities, particularly those that are lower resourced and less likely to have a paramedic available to respond.
Interestingly, field delivery by EMS was documented in only 41% of activations for an out-of-hospital delivery, indicating that most patients may have completed delivery prior to EMS arrival. This rate is similar to previous studies across a wide range of settings (Citation2). However, only 2% of activations with a delivery complication included field delivery by EMS, with more of these patients found in a healthcare facility (e.g., a birthing center). As most complications were for hemorrhage, these patients represent a particularly high-risk subset where EMS clinicians may be presented with a critically ill patient in need of extensive resuscitation. Ensuring the adequacy of training and availability of appropriate equipment, medications, and protocols is critical to preparing the EMS crew to provide high-quality prehospital care in these situations.
This analysis revealed several areas of opportunity to improve prehospital care of obstetric patients. The National Model EMS Clinical Guidelines (Citation29), published by the National Association of State EMS Officials, provide consensus- and evidence-based clinical guidelines that can be adapted for state and local EMS agency use. Although supplemental oxygen to the mother has not been found to improve neonatal outcomes (Citation30), the 2017 (Version 2) guideline on prehospital childbirth specifies that high-flow oxygen should be administered to the mother if any delivery complication occurs; however, very few activations had evidence of oxygen administration. The 2017 (Version 2) guidelines did not include specific treatment recommendations for postpartum hemorrhage, despite ample evidence and in-hospital guidelines (Citation31–33). Notably, Version 3, published in March 2022, does include a hemorrhage section that recommends considering administration of blood products, oxytocin, and TXA. Anecdotally, few EMS agencies authorize or carry blood products or oxytocin; TXA is more commonly used and authorized for use in hemorrhagic shock. Improving access to these first-line treatment options, such as by carrying oxytocin or changing protocols to administer TXA during postpartum hemorrhage, may be one strategy to improve prehospital obstetric care.
There was also evidence to suggest poor documentation of obstetric care in NEMSIS. Procedures commonly expected after out-of-hospital delivery were not frequently documented, including no records with documentation of fundal massage and few with clamping and cutting of the umbilical cord. It is likely that several of these interventions were provided by EMS, and perhaps documented in the free-text narrative field that is not available for research purposes. Improved documentation practices could facilitate more research into prehospital care practices for many conditions, including structural changes to the software EMS clinicians use to group together common interventions to prompt complete documentation. Additionally, the creation of a registry of prehospital births with more complete data entry practices, similar to those for cardiac arrest and trauma (Citation34, Citation35), would further facilitate the ability to assess and improve the quality of prehospital obstetric care.
This analysis has several limitations. As noted above, variations in documentation standards and quality present a potential for misclassification. We identified out-of-hospital deliveries and complications based on the EMS documented symptoms, impressions, and procedures, which may have resulted in under- or overestimation due to incorrect or inaccurate documentation. Other data fields that would have provided more nuanced information, such as the EMS clinician’s narrative report of the event, are not available for research purposes. In particular, narrative report review among a sample of out-of-hospital deliveries in Michigan found that 32% documented a maternal or fetal complication (Citation36) compared to 17% in this dataset; thus, underestimation of delivery complications was likely. NEMSIS is a convenience sample, and records do not allow for tracking of patients across time or events. Multiple records could be generated for a single event; thus, the unit of analysis is EMS activation rather than a unique patient or event. We attempted to limit duplication of patients by restricting to only those activations with the EMS crew treated and transported the patient. We are also unable to examine maternal or neonatal outcomes in these data as well as patient-level factors, such as socioeconomic status, health insurance status, access to prenatal care, and distance to the nearest hospital. Finally, there was a high rate of missingness for individual patient race/ethnicity. For that reason, we focused on community-level markers of diversity that may be more indicative of structural disparities in EMS care.
Conclusion
Using the largest repository of U.S. EMS patient care records, we report on characteristics of out-of-hospital deliveries and complications attended by EMS. We found potential disparities in level of care, clinical care provided, and measures of access to definitive care (i.e., longer transport times) based on maternal age, community vulnerability, and urbanicity. We identified gaps in current practice, such as for postpartum hemorrhage, that could be addressed with changes in EMS clinical protocols and regulations. We also identified a critical need to improve the documentation of EMS-attended out-of-hospital deliveries to better understand and track the quality of care for these high-risk situations. Together, this work provides a more comprehensive understanding of the epidemiology of out-of-hospital deliveries that can inform the additional skills, equipment, and training for EMS clinicians that would be needed for optimal prehospital obstetric care.
Supplemental Material
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Data Availability Statement
The dataset supporting the conclusions of this article is available from the National Emergency Medical Services Information System Technical Assistance Center (https://nemsis.org) through a data request process.
Disclosure Statement
No potential conflict of interest was reported by the author(s).
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References
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