Expecting sudden cardiac arrest most likely falls at the end of our list of worries. More specifically, unexpecting mothers; inundated with other concerns like pregnancy loss, preeclampsia, or gestational diabetes, maternal cardiac arrest is probably one of the more unanticipated complications during pregnancy.

While true that most expecting mothers shouldn’t worry about such a complication, it is still plenty threatening. Dr. Carolyn Zelop explained that “with pregnancy, you have two patients built into one and it’s a very different clinical scenario that a lot of folks are surprised by, stunned by, and even people who have a lot of expertise in resuscitation don’t have any expertise in this.”

Few health care providers are experienced in treating maternal cardiac arrest but by including it in standard ACLS training, maternal survival can be optimized. Dr. Zelop et al., in their AJOG report explains how “resuscitative interventions are concurrent rather than sequential” and that it is important for all providers to be prepared for maternal cardiac arrest.

For over 20 years, Dr. Zelop has been working with fetal hearts and explains that “maternal mortality has gone up more than 50% since 2000…we were losing moms and we couldn’t resuscitate them and there were a lot of system errors.” In Avive’s most recent article on gender disparities and CPR, it was reported that women receive CPR 30% less frequently than men. In the case of a pregnant woman, this number drops even lower because bystanders are simply more fearful of the consequences.

A report explained that “while the global maternal mortality ratio (maternal deaths/100,000 live births) has decreased in the last 25 years from 281.5-195.7, the maternal mortality ratio has actually increased from 16.9- 26.4 in the United States.” It further explains how mandating maternal CPR in relevant institutional settings can bolster in-hospital maternal survival.

In absolute figures, maternal sudden cardiac arrest is rare but it still causes a large number of deaths globally. An American Heart Association report, in which Dr. Zelop was the second author, painted an even grimmer picture at or near delivery, with 1 in 12,000 women admitted for delivery in America experiencing cardiac arrest. That number is potentially underreported, because of maternal cardiac arrest incidents that occur out of the hospital setting.

Improvements in general maternal care and public access defibrillation are however estimated to have increased survival rates from 52% in 1998 to 60% in 2011.

The reasons for the increased risk of maternal cardiac arrest are varied. The causes can be divided into three related categories: obstetric, non-obstetric, and iatrogenic.

• Obstetric causes include hemorrhage, eclampsia, and amniotic fluid embolism.

• Some prominent non-obstetric causes are sepsis, pulmonary embolism, preexisting cardiovascular disease, and stroke.

• Anesthetic complications during delivery or testing is a prominent iatrogenic cause. According to a UK study, complications brought about by obstetric anesthesia cause one in four cardiac arrests that happen in pregnant women.

The 2018 AJOG publication cited that anesthesia being one of the greater causes of maternal cardiac arrest means that anesthetic care must be made a priority. Intubation is one of these requirements for prioritizing anesthetic care. Resuscitation and timely CPR can be hindered by intubation in a mother, so CPR must be prioritized over intubation.

Physiological changes that manifest because of pregnancy include increased sensitivity to oxygen deprivation which can eventuate in disorders like hypoxemia and aspiration. There is a 20% increase in oxygen consumption and a 40% increase in cardiovascular metabolism to accommodate the fetus. The altered levels of hormones like progesterone and estrogen restrict air passages further cramping airways.

In a hospital setting, it is recommended that fetus monitors are removed before defibrillation to prevent possible electric arcing. The onset of cardiac arrest in a pregnant mother inevitably places the fetus in danger. Fetuses that are beyond 23 weeks in gestation are considered viable and doctors can, therefore, consider a perimortem cesarean section. In many cases, the delivery of the fetus through this method will result in the stabilization of the mother because arteriovenous compression caused by a gravid uterus stops. According to a review of maternal cardiac arrest, perimortem cesarean section should be conducted within 4 to 5 minutes of cardiac arrest onset to maximize the survivability of both the fetus and the mother.

The intention is not to create fear in expecting mothers and families, rather the goal is to raise awareness and offer a working solution. It is commonly misperceived that pregnant women, in the event of SCA, should not receive CPR and resuscitation AED shocks, that it can be harmful to the fetus. The standard algorithm for resuscitation largely remains constant for pregnant women in SCA, and it is expected that pregnant women receive the same quality CPR and AED shocks as anyone else. Defibrillation remains unchanged since it is not known to pose any significant risk to the mother or the fetus. That is, upon observing maternal cardiac arrest, a responder should immediately call 911 then lay the mother on her back, open her airway, check for the absence of breathing and perform CPR with 30 chest compressions and 2 rescue breaths. A responder should then continue by using an AED and continuing CPR until emergency services arrive.