Leave no woman behind: a call to standardize and expand the Get With The Guidelines registry

TO THE EDITORS: The April issue of the American Journal of Obstetrics & Gynecology included a population-based propensity score matching study by Thomas et al, evaluating the survival rates and processes-of-care between maternal and nonmaternal in-hospital cardiac arrest (IHCA).¹ The authors conclude that although concerns have been raised about resuscitation outcomes in women with maternal IHCA, the rates of survival and resuscitation process-of-care were not worse for patients with maternal IHCA than for those with nonmaternal IHCA. However, they conclude that there is still room for improvement in the management of maternal IHCA. We commend the authors for trying to better understand the gaps in the care of maternal IHCA.

We agree with the authors that using observational data from the Get With The Guidelines (GWTG) registry has limitations. The authors define maternal cardiac arrest (MCA) as “a cardiac arrest that occurs in women with an obstetric diagnosis or occurrence in a delivery suite.” However, one-third of MCA events occur postpartum.² The Guidelines do not specify what “postpartum” could mean (eg, it just says “recently pregnant”). Given that the postpartum period extends for 1 year after delivery, it is possible that the “nonmaternal” IHCA cohort in this study included several patients who would have been reclassified as postpartum and included in the maternal IHCA cohort. In addition, the GWTG form does not list the major causes of MCA as comorbidities of pregnancy or delivery (ie, anesthesia exposure, suspected amniotic fluid embolism, etc.). Furthermore, the only unique technique to MCA resuscitation mentioned on the GWTG form is left uterine displacement. Other known techniques to improve the time to return of spontaneous circulation (ROSC), such as resuscitative cesarean delivery, are not accounted for on the current version of the form (https://www.heart.org/-/media/Files/Professional/Quality-Improvement/Get-With-the-Guidelines/Get-With-The-Guidelines-Resuscitation/CPA-CRF_Jan2021.pdf). Data on the survival rates and processes-of-care for maternal IHCA will continue to have limitations until all hospitals universally use and accept the GWTG registry and the registry adds pregnancy-specific resuscitation techniques and accounts for events occurring up to 1 year postpartum.

The hospital discharge survival rates for maternal IHCA have been reported to be as high as 58.9%³ compared with a median 25.1%⁴ for nonmaternal IHCA. Given that the expectation for survival may be higher for maternal IHCA, these studies provide evidence that maternal IHCA outcomes are worse than expected than nonmaternal IHCA. The authors did observe that there were delays in resuscitation processes (eg, administration of epinephrine and defibrillation) on labor and delivery units. We agree that this is likely because of obstetrical hospital staff not routinely training in Advanced Cardiac Life Support (ACLS) protocols or participating in cardiac arrest simulation training. Unfortunately, even if the staff were required to receive regular ACLS training, most of the current educational offerings lack sufficient education and training in pregnancy-specific etiologies, team training, and modification of resuscitation skills to treat maternal IHCA.

The authors do not address issues of race and sex in their study. Because cardiovascular disorders are the leading cause of maternal mortality⁵ and MCA is the final common pathway for maternal death, we would anticipate the demographics of their population with maternal IHCA to reflect the maternal mortality demographic for the United States. However, most patients with maternal IHCA in this cohort were White, whereas most maternal deaths in the United States occur in Black patients.⁶ This may reflect the demographics of the GWTG participating hospitals or differences in the location of cardiac arrest (eg, in-hospital vs out-of-hospital) by race, which may limit the generalizability of their findings. Studies have also previously suggested that there are gender differences in resuscitation outcomes and applications, with bystander cardiopulmonary resuscitation and even better survival to discharge seen in male patients.⁷ We recommend that future research compare maternal IHCA not only with non-MCA but also with age-matched males who have IHCA, given the potential for sex equity concerns.

Currently, the best evidence on maternal IHCA suggests that most pregnant women should survive this event and walk out of the hospital. The study highlighted the limitations of using a registry that is not universally accepted by hospitals throughout the United States and the urgent need for a mandatory nationwide registry for both maternal in-and out-of-hospital cardiac arrest. This registry can be expanded to include maternal out-of-hospital cardiac arrest (OHCA) and standardization to include the pregnancy and postpartum status up to 1 year and pregnancy-specific resuscitation techniques; this will allow researchers and policymakers to suggest optimal prevention strategies for both maternal OHCA and IHCA that are based on the latest performance, trends, and outcomes in maternal cardiac arrest.

This study also provided evidence that at best, women studied on a population level are only achieving survival rates that match their nonpregnant propensity-matched controls, which appears to be worse than expected on the basis of current evidence. The authors did highlight the process delays for maternal IHCA occurring in the labor and delivery suite, where most (63.8%) of the maternal IHCA events occurred. The key drivers of progress to reduce maternal deaths are expanded education and team training to properly resuscitate patients with MCA. We believe that these are necessary and urgent improvements, given the rising rates of maternal deaths in the United States.⁸ In addition, it is imperative to require continuing education in pregnancy-specific resuscitation to reduce disparities, optimize maternal outcomes, and prevent further maternal death.