By Matthew E. Fink, MD
Louis and Gertrude Feil Professor and Chair, Department of Neurology, Associate Dean for Clinical Affairs, New York Presbyterian/Weill Cornell Medical College
Stroke during pregnancy or the puerperium is a rare event but accounts for a considerable part of maternal morbidity and mortality. Approximately 15% of maternal deaths are caused by pregnancy-associated stroke. The incidence has been increasing in all countries, particularly in wealthy industrialized countries, where pregnancy is being delayed considerably and other cardiovascular risk factors, such as hypertension, diabetes, cardiovascular disorders, and obesity, have taken on greater importance.
These investigators reviewed a chart-validated data registry in Finland, where all citizens are covered by health insurance, and there is a centralized Medical Birth Register linked to Hospital Discharge Register to identify all women who are pregnant and had incident stroke. The investigators performed a retrospective case-control cohort study in Finland covering the years 1987 through 2016. They identified all women with ischemic stroke, cerebral venous thrombosis, and intracerebral or subarachnoid hemorrhage during pregnancy or the puerperium. Medical records were reviewed to verify the diagnosis. The incidence of pregnancy-associated stroke was calculated over five-year age groups and incidence was calculated per number of deliveries. Three matched controls were selected for each case of pregnancy.
The overall incidence of pregnancy-associated stroke was 14.5 per 100,000 deliveries. It increased from 11.1 to 25.2 per 100,000 deliveries over the years 1987 to 1991 compared to 2012 to 2016 (P < 0.0001). Age was an important factor. Stroke incidence increased by age from 9.8 to 29.9 per 100,000 deliveries from 20-24 years of age compared to age > 40 years (P < 0.0001). Stroke incidence was fivefold greater in the early postpartum period compared to the first trimester, and overall maternal mortality was 6.6%. The following significant risk factors were found in a multivariable analysis: smoking, migraine, and hypertensive disorders of pregnancy. Greater attention should be paid to modifiable cardiovascular risk factors in women who are pregnant, particularly in older age groups.