Stroke is a rare but potentially devastating occurrence during pregnancy and the postpartum period. Maternal mortality is reported to be as high as 26%, and survivors may face long-term neurologic sequelae. Associated fetal mortality and morbidity also remain high. Although stroke is not preventable, early intervention can be key to saving lives and preserving brain function in some patients.
Therefore, even if the likelihood is that an obstetrician will never encounter a patient who suffers a stroke, it is critical that we all make the diagnosis promptly, obtain neurologic and other consultations appropriately, and direct state-of-the-art treatment of cerebrovascular disorders in this special population.
It is important to recognize that stroke occurs in young women of childbearing age at a rate of 10.7 per 100,000. Some have postulated that the risk is elevated during pregnancy for a number of reasons, including hypercoagulability, venous stasis, and blood pressure fluctuations. Indeed, some estimate that the risk of stroke is 13-fold higher in pregnant than in nonpregnant women, although the rarity of the condition makes the true prevalence a matter of debate.
Postpartum Risk Is Higher
The risk of stroke in the postpartum period is almost certainly higher still. Postpartum strokes generally occur from 5 days to 2 weeks after delivery—a vulnerable time when a headache from cerebral vasoconstriction syndrome may be mistaken for postepidural puncture syndrome.
The issue of stroke during pregnancy and the postpartum period is of increasing relevance to obstetricians. The incidence of stroke rises with age, and women are becoming pregnant at older ages than ever before; obstetric patients aged 45–50 years have become increasingly common. Obesity is also a risk factor for stroke, and pregnant women mirror American society at large, in which obesity has become epidemic. Longstanding hypertension and diabetes mellitus, both associated with obesity, further increase the risk of stroke.
Stroke can happen at any time. The clinical presentation is similar to that seen in nonpregnant patients; however, these symptoms can mimic those seen in preeclampsia and eclampsia, and the possibility of stroke may be overlooked.
Another potential delay in diagnosis and treatment may arise in patients who, like many nonpregnant patients, hesitate to seek immediate medical care when experiencing symptoms of stroke. Headache, for example, is common in pregnancy. Some women do not take it seriously unless it is very severe.
It is prudent to counsel all patients—and especially those with relevant risk factors—to seek care for any symptom that may be associated with stroke: headache; visual changes; epigastric pain; seizures; nausea and vomiting; or neurologic defects (focal or global). Severe hypertension and widened pulse pressures are symptomatic of stroke as well.
Cerebrovascular events may be associated with drug ingestion, infection, neoplasms, or trauma, as well as with metabolic factors. Researchers have been unable to determine the etiology of stroke in 23%–32% of cases.
Many medical conditions increase the risk of stroke, including cardioembolic diseases such as rheumatic heart disease or atrial septal defects; atherosclerosis (which may account for 15%–25% of cerebral infarctions in pregnancy); and disorders such as sickle cell disease, thrombophilias, central venous thrombosis, arteriovenous malformations and aneurysms, and cerebral vasoconstrictive syndrome.
Risk factors believed to be associated with pregnancy and the postpartum period include cesarean delivery and pregnancy-related hypertension. The link to hypertensive disorders of pregnancy seems to be an association in numerous studies, yet it is important to recognize that hypertension may be the result of a stroke rather than its cause. Seizures and central neurologic insult can undermine cerebral autoregulation and cause blood pressure to rise. Eclampsia and stroke produce similar clinical laboratory and neuroimaging findings.
Review of Stroke Cases
In a review of our 20-year institutional experience with postpartum stroke, we identified 20 cases among 130,000 deliveries at the E.H. Crump Women's Hospital of the University of Tennessee in Memphis (Am. J. Obstet. Gynecol. 2000;183:83–8).
In all cases, patients were discharged and later readmitted with findings consistent with a diagnosis of stroke. The mean age of these patients was 26 years; the mean gestational age at delivery was 27.3 weeks; and the mean birthweight was 2,617 grams, representing a group of patients with earlier deliveries and lower birthweights who were somewhat older than our obstetric population in general.
Of these 20 patients, 6 had a history of chronic hypertension. Preeclampsia was present in four pregnancies, and eight patients (40%) underwent a cesarean delivery, a rate approximately threefold higher than that in our overall obstetric population.
C-sections were performed for various reasons: three for nonreassuring fetal status, three for failure to progress, one for malpresentation, and one as an elective repeat C-section. Importantly, no intrapartum or postpartum complications presaged stroke in any patient. A review of antepartum, intrapartum, and in-hospital postpartum blood pressure values found normal measurements or well-controlled blood pressure in all women except one, whose blood pressure was elevated on postpartum day 3.