Stroke in women during pregnancy is three times higher than stroke in non-pregnant woman of the same age, according to a Canadian study published today in the International Journal of Stroke, which reveals that roughly 30 out of 100,000 women will experience a stroke during the pregnancy period. The highest risk occurs during the periods just before or following birth.
The systematic review and meta-analysis assessed the incidence of stroke during pregnancy and the six weeks following birth. It looked at all international studies published between 1990 and January 2017 reporting on stroke incidence during pregnancy. Eleven studies met the stringent inclusion criteria. Stroke during delivery was reported in three studies. Mortality was reported in 10 studies.
“Pregnancy can affect vascular risk factors, like diabetes or blood pressure, but many people don’t recognize there is an increased risk of stroke,” says study co-author Dr. Rick Swartz, stroke neurologist; medical director North East GTA Regional Stroke Program, director of the Stroke Research Unit at Sunnybrook Health Sciences Centre, and assistant professor, Department of Medicine, University of Toronto. “Stroke is a leading cause of death and disability in adults and when stroke occurs as a complication of pregnancy, the impact on the mother, child and families can be devastating.”
Despite advances in stroke treatment, prevention and care, stroke remains a major cause of maternal death and a devastating cause of maternal morbidity around the world. Given the profound impact of stroke on women of childbearing age, their families and health systems, it is vital to have accurate rates of stroke in and around pregnancy to facilitate both clinical decision-making and health system planning.
What precisely increases stroke risk in pregnant women requires more study. However, early findings suggest hormonal changes and certain conditions like preeclampsia may increase risk. The condition — a sudden onset of very high blood pressure can be potentially life-threatening for moms-to-be and their babies if left untreated. High blood pressure is the number one risk factor for stroke but it can be managed.
There may also be geographic differences between countries that may reflect factors including genetics, health-care systems and other not-yet identified reasons. The meta-analysis identified a potential trend of lower event rates in some countries; seemingly those with more universal pre-natal care.
“All pregnant women are at a low, but increased risk of stroke,” says study co-author Dr. Patrice Lindsay, director of stroke, Heart & Stroke. “While all pregnancy-related stroke risk cannot be eliminated, there are things women can do to decrease their risk, including following a healthy diet, being physically active and smoke-free, managing blood pressure and stress and limiting alcohol consumption.”
The study found that pregnancy increases the risk of stroke for a number of reasons, including: pregnancy-related high blood pressure disorders (chronic hypertension, gestational hypertension, pre-eclampsia, eclampsia) and their complications (renal damage, HELLP syndrome), blood and blood clotting changes in the third trimester and post-partum periods, hyperemesis (persistent severe vomiting which can lead to dehydration) resulting in increased concentration of cells and solids in the blood, and changes to cerebral vasculature. Regular follow up with one’s physician throughout pregnancy is especially helpful to monitor stroke risk factors such as pre-eclampsia, blood pressure and blood sugar, and to discuss any symptoms of concern.
While there was minimal evidence surrounding recurrence rates in subsequent post-stroke pregnancies, Dr. Lindsay notes that women who have had a previous stroke can get pregnant and should work closely with their healthcare providers to ensure that their risks and prevention needs are addressed. Future research is needed to address this gap.
Geneviève was six months pregnant when the unexpected happened
Everything changed for 26-year-old Geneviève Morel just before midnight on March 31, 2013, when she experienced a stroke .
“Lightning exploded in my head, “says Geneviève. In shock, her partner Jonathan dialed 9-1-1. She was diagnosed in the emergency department with a cerebral hemorrhage, which was growing at an alarming rate.
She was 24 weeks pregnant.
Both lives were in danger: Hers and the baby’s. Thankfully, both she and the baby survived five hours of emergency surgery. The surgery saved her life, however the stroke was severe, and left her with some physical limitations, including being paralyzed on her left side. Her unborn baby seemed unharmed. “His little heart was still beating. That was all that mattered,” says Geneviève.
Throughout the rest of her pregnancy, Geneviève realized her life was changed forever, as she underwent therapy, relearning how to perform simple tasks such as sitting, feeding herself and dressing.
Three months after the stroke, she was overjoyed when a healthy baby Nathan entered the world. The next few months were full of obstacles and difficult days, as Jonathan took on the role of caring for both a newborn as well Geneviève, and she began a new outpatient rehabilitation program.
The cause of Geneviève’s stroke remains unanswered. Today, her recovery continues to improve: “Even though I have partial paralysis, I have high hopes for the future. I volunteer in a community resource centre in Laval for families at risk, and I am working on a career as a support aide specializing in physical conditioning and self-esteem.”
Canadian recommendations for healthcare providers
Specialists providing obstetrical or stroke care may encounter women with a past stroke wanting to get pregnant, or women like Geneviève who have a stroke during or immediately after a pregnancy. How should these cases be managed? Currently there is limited evidence to guide healthcare professionals in these medical decisions.
In a second phase of this work, the study authors will release a medical consensus statement on Monday at the Canadian Stroke Congress – providing recommendations to guide healthcare professionals on preventing and treating woman with stroke prior to, during, and right after pregnancy.
“Ensuring the health of the mother is needed to ensure the health of baby,” says Dr. Swartz. “Organized approaches to the management of this high-risk population, informed by existing evidence and the expertise of stroke and obstetrical specialists are essential.”
Ongoing trials from both stroke and obstetrical literatures are continually monitored and reviewed as part of the Heart & Stroke stroke best practice process, and the consensus statement will be updated as new evidence becomes available.
The study authors say further research on stroke in pregnancy and the impact of geographic variations in risk factors and outcomes, improvements in data capture and data quality for stroke in pregnancy, and rational approaches to treatment in the absence of randomized trial data are urgently needed.
All Canadians should also know the FAST signs of stroke and to react to them as a medical emergency:
FACE – is it drooping?
ARMS – can you raise both?
SPEECH – is it slurred or jumbled?
TIME to call 9-1-1 right away
Richard Swartz (Sunnybrook), Megan L Cayley (Sunnybrook), Norine Foley (Western University), Noor Niyar N Ladhani (Sunnybrook), Lisa Leffert (Harvard University), Cheryl Bushnell (Wake Forest Baptist Health), JA McClure (workHORSE Consulting Group), and Patrice Lindsay (Heart & Stroke)
Heart & Stroke, Canadian Institutes of Health Research, Heart & Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Department of Medicine, University of Toronto Department of Medicine
- A stroke is a sudden loss of brain function.
- 62,000 strokes occur in Canada each year – that is one stroke every nine minutes.
- Each year, more than 13,000 Canadians die from stroke.
- 80% of people survive stroke.
- Brain cells die at a rate of 1.9 million per minute after stroke.
- More than 400,000 Canadians live with long-term disability from stroke and this will almost double in the next 20 years.
- Stroke can happen at any age. Stroke among people under 65 is increasing and stroke risk factors are increasing for young adults.
Heart & Stroke
More moments. More life. That’s why Heart & Stroke leads the fight against heart disease and stroke. Powered by donors and volunteers, we fund life-saving research and help Canadians lead healthier lives.
Sunnybrook Health Sciences Centre
Sunnybrook Health Sciences Centre is inventing the future of health care for the 1.2 million patients the hospital cares for each year through the dedication of its more than 10,000 staff and volunteers. An internationally recognized leader in research and education and a full affiliation with the University of Toronto distinguishes Sunnybrook as one of Canada’s premier academic health sciences centres. Sunnybrook specializes in caring for high-risk pregnancies, critically-ill newborns and adults, offering specialized rehabilitation and treating and preventing cancer, cardiovascular disease, neurological and psychiatric disorders, orthopaedic and arthritic conditions and traumatic injuries.
Canadian Stroke Congress
Co-hosted by Heart & Stroke and the Canadian Stroke Consortium, the Canadian Stroke Congress is a uniquely Canadian forum for experts to share the latest research findings, exchange ideas, and make the connections which will change the future of stroke. It brings together researchers, neurologists, nurses, rehabilitation specialists, policy makers, health system decision makers – and many others – in an unprecedented opportunity to improve the brain health of Canadians.
For media interviews, please contact
416-467-9954, ext. 102
Nadia Norcia Radovini
Sunnybrook Health Sciences Centre