Cerebrovascular diseases in pregnancy and puerperium
Lamy, C.; Sharshar, T.; Mas, J.L.
Revue Neurologique (Paris) 152(6-7): 422-440
1996
ISSN/ISBN: 0035-3787 PMID: 8944239 Document Number: 466623
The incidence, prognosis and causes of strokes associated with pregnancy or puerperium are poorly known, and we do not know whether and to what extent they differ from those of the general female population of childbearing age. Based on early and mostly hospital-based studies, it has been claimed that pregnancy increases the likelihood of cerebral infarction to about 13 times the rate expected outside of pregnancy. However, because of methodological weaknesses, these estimates must be regarded with caution. In a recent study in Ile de France, the incidence of arterial ischemic strokes associated with pregnancy or early puerperium was 4.3 per 100,000 deliveries (95% confidence interval, 2.4 to 7.1), a rate not much different from that for all women of childbearing age. Ischemic strokes related to various etiologies have been reported in pregnancy and the puerperium. Their relative frequency is poorly known because there are no recent large series of pregnancy-related ischemic strokes benefiting from detailed investigation with modern imaging techniques. Most of the known causes of ischemic stroke in the young been reported during pregnancy. In most of these conditions, it is uncertain whether pregnancy is coincidental or plays a role in the occurrence of stroke. Among pregnancy-specific causes, eclampsia may be associated with focal neurological deficits of sudden onset, consistent with a clinical diagnosis of stroke. However, the precise pathogenesis of these stroke-like focal deficits remains poorly understood. Except for some women who have persisting neurological deficits and neuroradiological abnormalities suggesting brain infarction, the reversibility of the neurological clinical signs and neuroradiological lesions within a few days or weeks in most cases argues against the existence of true cerebral ischemic necrosis. The two other pregnancy-specific causes - choriocarcinoma and amniotic fluid embolism - are rarely responsible for focal cerebral ischemia. Other diseases such as peripartum cardiomyopathy and postpartum cerebral angiopathy were initially considered as pregnancy-specific causes but subsequently reported outside of pregnancy. In a significant number of patients, the cause of the stroke remains undetermined, despite an extensive etiological workup. Whether hypercoagulable state and vessel wall changes associated with pregnancy may play a role in the occurrence of these otherwise unexplained ischemic strokes remains unknown. Too frequently, the stroke is considered at the first attempt as a complication of pregnancy and another underlying etiology may be missed. Therefore, evaluation of arterial ischemic stroke in pregnancy should proceed as in the non-pregnant state. There are no follow-up studies that consider the risk of recurrent stroke in future pregnancies. No data are available on the risk associated with use of oral contraception in a woman who had ischemic stroke during pregnancy. The frequency of cerebral venous thrombosis associated with pregnancy and the puerperium is not precisely known. Indeed, epidemiologic studies have been difficult to perform because cerebral venous thrombosis may have a misleading presentation and a definite diagnosis requires angiography, MRI or autopsy. The incidence of cerebral venous thrombosis has been estimated at 10 to 20 per 100 000 deliveries in occidental countries, whereas rates of 200 to 500 per 100,000 deliveries have been reported in India. The pregnant and puerperal state accounts for 5 to 20% of all cerebral venous thrombosis in occidental countries; this proportion may reach 60% in developing countries. Labor and delivery are characteristically normal in occidental countries. The occurrence of cerebral venous thrombosis is clearly linked to the puerperial state, suggesting a direct role of the puerperial state. However, cerebral venous thrombosis during pregnancy or puerperium has been related to various etiologies, stressing the need for an etiological work-up, particularly when the thrombosis occurs during pregnancy. The mean incidence of subarachnoidal haemorrhage in pregnancy or the puerperium is estimated at 20 per 100,000 deliveries, a risk calculated as 5 times greater than outside pregnancy. However, methodological weaknesses also apply to these data. The most common cause is rupture of an arterial aneurysm. Although this is a controversial issue, the increased tendency of aneurysmal hemorrhage to bleed with advancing gestational age suggests that hemodynamic, hormonal or other physiological changes of pregnancy may play a role in aneurysmal rupture. The classic notion that rupture of an arterial aneurysm occurs more frequently during labor has not been confirmed. Most authors agree that surgical management after subarachnoid hemorrhage in pregnancy should be the same as that in the non pregnant state. Data specifically devoted to intraparenchymal haemorrhages in pregnancy are very scarce. In the "Ile de France" study, t heir incidence rate was 4.6 per 100,000 deliveries (95% confidence interval, 2.6 to 7.5). The finding that, in pregnancy, intraparenchymal hemorrhages were as common as ischemic strokes suggests that pregnancy may increase the risk of cerebral hemorrhage. The leading causes were eclampsia and ruptured vascular malformations. Whether pregnancy increases the risk of rupture of an arteriovenous malformation is controversial.