Introduction

While the origin of the perimortem cesarean section is debated, the procedure is reported to have been performed in all cultures dating back to ancient times [1]. The term “cesarean section” is said to come from the performance of the postmortem section, dating back to 715 BC when Roman king Numus Pompilius decreed that no child should be buried within its mother [1,2]. This was first known as Lex Regis (the law of the king) and later translated into Lex Cesare (the law of Caesar), leading to the term cesarean section. This procedure was described widely through the Middle Ages to aid with baptism, and multiple royal and religious decrees reinforced the performance of postmortem sections. While initially performed to aid in burial, the procedure was later performed in an attempt to save the infant and mother [3]. Literature from the 1800s demonstrates a debate over the pros and cons of the procedure, and medical reports of infants surviving surface at that time [2]. Because of the high frequency of maternal mortality, as well as high rates of sepsis, dehydration, and hemorrhagic shock as the causes of maternal death, infants often died before the mother and survival following postmortem sections remained low for centuries [2,4].

Over time, the leading causes of maternal mortality in pregnancy have changed to trauma, cardiac disease, and embolism [4–6]. In these cases, the mother and infant are generally in good health until an insult results in maternal cardiac arrest. Thus, performance of a postmortem c-section could be more likely to result in birth of a live infant than described historically. The term perimortem cesarean section (PMCS) began to be used widely following a landmark literature review of postmortem cesarean section cases by Katz et al. [5] Of 269 cases reported from 1879 to 1985, 188 infants (70%) survived, a higher infant survival rate than previously considered. The majority of surviving infants (with timing records) were delivered within 5 minutes from death of the mother. All but one neurologically intact infant was delivered within 15 minutes. Katz et al. recommended performance of PMCS within 4 minutes of maternal arrest, with delivery by 5 minutes, in any case with fetal viability. This became known as the “4-minute rule” and remains widely referenced today [7]. A follow-up review of 38 cases between 1985 and 2004 supported this recommendation [4].

Potential benefits of perimortem cesarean section

The reasons for performing PMCS have changed over time. While first primarily performed for burial and religious reasons and later to attempt survival of the fetus who would otherwise meet certain death, cases of maternal survival after PMCS reveal the additional potential benefit of the procedure as part of maternal resuscitation. In a pregnant woman at term, the great vessels are compressed by the uterus, which leads to a reduction in cardiac output by two-thirds [1,2,4,7–9]. Considering that cardiopulmonary resuscitation (CPR) already produces a cardiac output that is only one-third of normal, chest compressions in a supine pregnant mother under the best circumstances produce a cardiac output that is 10% of normal. Emptying the uterus through PMCS alleviates compression of the inferior vena cava, improves venous return, and allows redistribution of uterine blood to other organs, which under normal conditions at term contributes up to 25% of cardiac output. Emptying the uterus also increases the functional residual capacity of the mother’s lungs, allowing for better oxygenation [1,10]. In combination, this may improve the effectiveness of CPR and lead to successful resuscitation of the mother after delivery of the infant.

In the landmark review by Katz et al., 12 cases were identified where there was sudden and often profound improvement in the mother’s condition once the uterus was emptied [5]. There have been multiple additional reports of maternal survival after PMCS, including 13 of 38 mothers discharged in good condition in Katz et al.’s follow-up review of PMCS cases [4]. Dijkman et al. reviewed all cases of maternal cardiac arrest in The Netherlands from 1993 to 2008 and found eight of 12 mothers who regained cardiac output after PMCS, though only two ultimately survived [11]. In none of these cases was PMCS performed within 5 minutes, and timing may have contributed to the ultimate outcomes. In another review of 94 PMCS cases, the authors determined that PMCS was beneficial to the mothers in 31.7% of cases, without demonstration of harm in any case [12]. Because of this potential effect on maternal resuscitation, it has been suggested that physicians should perform PMCS regardless of the gestational age or fetal viability, without delays to assess the status of the infant [11].

Performance of perimortem cesarean section in the field

Only a few cases of PMCS performed in the field have been reported in the modern medical literature. In all of these cases, PMCS was performed by a physician working as part of an EMS team. Kupas et al. reported the performance of a PMCS on a 39-year-old woman at 39 weeks gestation who suffered a myocardial infarction [13]. PMCS was performed by an emergency medicine resident functioning as a flight physician, along with a physician neighbor. Neither mother nor infant survived. Bowers and Wagner similarly described a 31-year-old woman at 37 weeks gestation who was involved in a motor vehicle crash into a building [14]. PMCS was performed by an emergency medicine resident as part of a physician/nurse flight team. Neither mother nor infant survived. Kue et al. reported the performance of a PMCS on a 21-year-old woman at unknown gestation involved in a motor vehicle collision [15]. PMCS was also performed by a flight physician, who first performed an ultrasound and determined there was no maternal cardiac activity, but there was fetal cardiac activity. CPR had been ongoing for over 25 minutes prior to PMCS and both mother and infant ultimately died. In each of these cases, cardiac arrest likely ensued for at least 25 minutes prior to PMCS, which may have contributed to the ultimate outcomes.

The performance of PMCS in the out-of-hospital setting involves a number of challenges not encountered in the hospital. PMCS is not commonly part of a nurse or paramedic scope of practice and the absence of a physician as part of an EMS team will severely limit the ability to perform this procedure, regardless of maternal or fetal outcome [14]. Therefore, even when medical oversight is contacted, performance of PMCS is almost certainly outside the nursing or paramedic scope of practice. At least one case of PMCS performed by paramedics has been reported in the lay press, and the appropriateness of the providers in performing the procedure was brought into question [16]. It is important for EMS medical directors and EMS providers to review regulations from medical control boards and state licensing bodies in order to develop policies and procedures for how to manage this rare field presentation.

On the rare occasion that a physician is present, resources in the prehospital setting may still be limited. Following PMCS, lack of sufficient personnel to resuscitate two patients may result in the need to cease resuscitation efforts on the mother in order to focus on resuscitation of the newly delivered infant. Furthermore, due to the rare in-field presentation of a pregnant woman in cardiac arrest, an EMS physician may not have adequate experience or training in performance of a PMCS. In these cases, if transport can be completed within 5 minutes of maternal arrest, one may consider delaying the procedure in order to transport the patient to a facility with the appropriate obstetrical and neonatal resources to manage this emergency. Similarly, transport teams without practitioners who are licensed to perform this procedure should be dissuaded from performing PMCS in the prehospital setting, focusing on rapid transport with ongoing resuscitation of the mother.