Pregnancy and the risk of hemorrhage from cerebral arteriovenous malformations

Abstract

We conducted a retrospective analysis of 451 women with an arteriovenous malformation (AVM) of the brain to determine whether pregnancy is a risk factor for cerebral hemorrhages. A total of 540 pregnancies occurred among our patient population, resulting in 438 live births and 102 abortions. There were 17 pregnancies complicated by a cerebral hemorrhage. The hemorrhage rate during pregnancy for women with an unruptured AVM was 0.035 +/- 0.005 per person-year. The hemorrhage rate for nonpregnant women of childbearing age with an unruptured AVM was 0.031 +/- 0.002 per person-year. Pregnancy did not increase significantly the rate of first cerebral hemorrhage from an AVM (P = 0.35). We found that women with an AVM face a 3.5% risk of hemorrhage during pregnancy. Pregnancy is not a risk factor for hemorrhage in women without a previous hemorrhage. This conclusion assumes no selection bias exists in our study population; a bias would be introduced if the risk of fatal outcome after a hemorrhage were greater in pregnant women than in nonpregnant women.

Anesthetic management for cesarean section in a patient with rupture of a cerebellar arteriovenous malformation

“…This fact results in significant differences between the neurosurgical management of ICH resulting from a rupture of an intracranial aneurysm and an AVM. Nevertheless, this lower rate of re-rupture in an AVM -approximating 3.5% [20] -is in no way insignificant, and approximately 10% of patients with an AVM have coincidental aneurysms.…”

“…Interestingly, the risk of hemorrhage from a cerebral AVM does not seem to be increased during pregnancy. In a retrospective analysis of 451 women with 540 pregnancies, the Massachusetts General Hospital investigators found that pregnancy did not increase the rate of first hemorrhage, no matter whether delivery was by the Cesarean or vaginal route [20]. During pregnancy, however, the re-bleeding rate may be increased, as compared with a non-gravid woman -26% versus 6%, respectively [22] -and may be due to laxity of blood vessels [25].…”

Cerebrovascular disease in pregnancy

“…The crude annual risk of first hemorrhage from an unruptured AVM is approximately 2% (1.3% to 3.9%), but the risk of recurrent hemorrhage may be as high as 18% in the first year, with uncertain risk thereafter [121,122]. In two series, the rate of AVM rupture during pregnancy varied from 3.5% [125] to 9.3% [126], with the greatest risk during the second trimester. The risk may extend into the third trimester, and theoretically may be exaggerated by the hemodynamic stresses of parturition [128].…”

“…• The frequency, prognosis, and management of AVMs has been recently reviewed [121][122][123][124][125][126][127]. The incidence of AVMs is estimated at approximately one per 100,000 in unselected populations, and point prevalence in adults is approximately 18 per 100,000.…”

Treatment of arteriovenous malformations of the brain

“…Other important factors influencing the natural history of brain AVMs include the fact that untreated AVMs in the posterior fossa demonstrate a particularly poor prognosis [8], small AVMs are significantly more likely than large AVMs to hemorrhage spontaneously [4], and there is an increased risk of hemorrhage associated with deep venous drainage [9], single draining veins [10], impaired venous drainage from stenosis [10,11], and coexisting aneurysms [11][12][13]. Finally, in a study comparing the cerebral hemorrhage rates of unruptured brain AVMs in pregnant women with those in nonpregnant women of childbearing age [14], pregnancy was not shown to be a significant risk factor for cerebral hemorrhage in women with unruptured brain AVMs.…”