Stroke in Pregnancy: Consensus Statements by the Canadian Stroke Best Practices Stroke in Pregnancy Writing Group.
Stroke, the sudden loss of neurological function due to neuronal injury of a vascular cause, is a leading cause of disability in adults. When stroke occurs during pregnancy, the impact on the mother, child and families can be devastating. A recent systematic review and meta-analysis funded by Heart & Stroke showed that stroke affects 30/100,000 pregnancies, roughly 3 times higher than the risk in young adults. Several aspects of pregnancy can increase the risk of stroke including: hypertensive disorders of pregnancy (gestational hypertension, preeclampsia with or without chronic hypertension, eclampsia, HELLP syndrome [hemolysis, elevated liver enzymes and low platelets syndrome]) and their complications: hematologic and prothrombotic changes, particularly in the third trimester and post-partum periods; hyperemesis resulting in hemoconcentration; and changes to cerebral vasculature (for example, reversible cerebral vasoconstriction syndrome (RCVS), as well as growth of existing arteriovenous malformations).
Given this etiological variability, the practical limitations to clinical research in pregnant patients with stroke, and the rarity of events, it is not surprising that there is limited literature to guide important management decisions. Yet, stroke is sufficiently common that most specialists providing either obstetrical or stroke care encounter either women with a past stroke wanting to get pregnant, or women who develop a stroke during or just after a pregnancy. Thus, there is a need for a rational approach to management decisions, based on the best available literature and guided by expert consensus.
Goal: To provide guidance on the management of stroke in pregnancy based on a critical appraisal of current evidence on obstetrical and stroke management informed by expert review and appraisal.
Scope: A set of two consensus statements have been developed based on the process above, focused on the unique aspects of pregnancy-related stroke. Part One addresses secondary prevention for women who have a history of stroke and are pregnant or planning to become pregnant; Part Two addresses treatment and management of a woman who experiences a stroke while pregnant or in the early postpartum period.
Most consensus statements within these documents are applicable to both ischemic and hemorrhagic stroke. In cases where the statements are applicable to one type or the other, these will be explicitly stated.
This set of consensus statements seeks to organize an approach and apply existing evidence to this specific subset of stroke patients (those pregnant) and this specific subset of pregnant patients (those with acute or previous stroke).
Target audience for this consensus statement is health care professionals that manage stroke and/or pregnancy, including maternal-fetal medicine specialists, obstetricians, family physicians, obstetrical medicine specialists, obstetrical anesthetists, internists, neurologists and critical care specialists, emergency medicine, radiologists, nursing professionals from neurological, obstetrical and critical care backgrounds, and stroke rehabilitation specialists
This consensus statement is focused on the issues of acute stroke management for a woman who experiences an acute stroke during pregnancy or in the postpartum period (generally including the first 12 weeks post delivery). It starts with the onset of stroke symptoms, followed by assessment, diagnosis and clinical decision-making regarding emergent treatments for these women. Stroke is a time-sensitive emergency condition. Once the patient is medically stable, the acute goals shift to ongoing management of stroke sequelae and rehabilitation requirements that meet the goals of the patient (Swartz et al 2017).
Stroke in pregnancy may be due to ischemia, hemorrhage, or venous occlusion. In general, risk factors for any cause of stroke in pregnancy may be related to pre-existing maternal risk factors (e.g.systemic hypertension, pre-existing arterio-venous malformation); physiologic changes in pregnancy (e.g., increased blood volume, hypercoagulability of pregnancy); or disorders of pregnancy (e.g. eclampsia, HELLP syndrome) (Butalia 2018, Demel 2018). Stroke in pregnancy most often occurs close to the time of delivery (~ 40%) and in the early post-partum period (~50%), with a lower incidence (10%) earlier in pregnancy (Swartz et al 2017, Cordonnier 2017, Demel et al 2018).
When a stroke occurs in pregnancy, a standardized approach to coordinated emergent care is essential for investigation, diagnosis, and intervention planning with the goal of maximizing maternal and fetal wellbeing. In pregnancy, care requires careful consideration of the potential impacts of a stroke on the mother’s health and survival, the fetus’ health and survival, multiple competing etiologies, and the need for interdisciplinary perspectives, all while time is of the essence. Typical decision-making related to the non-pregnant patient must be nuanced by the timing of stroke within the pregnancy, stroke severity, expected maternal outcomes, and the known or theoretical impact of decisions and interventions on the fetus. Whenever possible, the same decisions for acute treatment and management outside of pregnancy should be considered for a woman who is pregnant. In these cases, maternal health is prioritized and delays or deferral of critical steps in diagnosis and life-saving care due to pregnancy should be minimized.
The current research evidence for the areas addressed in this consensus statement varies considerably. Due to ethical issues, low case incidence and other practical reasons, there is a lack of high quality randomized controlled research evidence to guide decision making for emergency stroke management in a pregnant women. Areas where evidence is stronger includes many of the acute treatments for stroke outside of pregnancy, treatment of eclampsia outside of stroke, use of antiplatelet and antithrombotics in pregnancy, observational data on the effects of alteplase on pregnancy, and management of hypertension in pregnancy.
With this in mind, this consensus statement summarizes key considerations and the best available evidence for assessment and management based on factors related to the stroke and to the pregnancy. Largely, this statement reflects expert interpretation of available information, professional and clinical experience, and is meant to provide guidance while acknowledging the gaps in research evidence. Clinically, decisions should be made on an individual case basis and informed by the factors noted above. These consensus statements do not the take the place of integrated, interdisciplinary discussions related to specific cases, nor do they supersede clinician judgment and patient preferences. It should be acknowledged, however, that many decisions are time-sensitive and that rapid decision making is often necessary to prevent clinical morbidity and mortality.
The approach to secondary prevention and recurrent risk management of a woman with a prior history of stroke who then becomes pregnant is addressed in the first part of this Stroke in Pregnancy Consensus Statement series, and can be found at http://journals.sagepub.com/doi/full/10.1177/1747493017743801.
Refer to summary of the evidence for details information.