Arteriovenous malformations increase risk for pregnancy hemorrhage

By Ingrid Grasmo, MedWire Reporter

Women with a diagnosis of arteriovenous malformation (AVM) are at increased risk for severe bleeding during pregnancy, show study findings.

"Because of the increased risk of hemorrhage from AVMs during pregnancy, we recommend intervention in women who desire to bear children, particularly if the AVM has bled," say Rose Du (Brigham and Women's Hospital, Boston, Massachusetts, USA) and colleagues.

For the study, the team reviewed hospital records from 54 women with an angiographic diagnosis of AVM. Annual hemorrhage rates were calculated as the ratio of the number of bleeds to total number of patient-years of follow up.

A total of five hemorrhages occurring in four patients were identified from 62 pregnancies, yielding a hemorrhage rate of 8.1% per pregnancy or 10.8% per year.

Over the remaining 2461 patient-years of follow up 28 hemorrhages occurred, corresponding to an annual hemorrhage rate of 1.1%. The researchers note that most of the hemorrhages occurred after the age of 40 years.

Indeed, women with an AVM had a 7.91-fold increased risk for hemorrhage compared with women without the condition, which increased to 18.12-fold when the analysis was limited to patient follow up to the age of 40 years.

When the team reanalyzed the data, excluding hemorrhages on presentation and using patient-years of follow up rather than total since birth, the overall annual hemorrhage rate increased to 4.8%.

Given the study findings, the researchers recommended the protocol currently used in their hospital where AVMs discovered during pregnancy are treated early. Patients with unruptured AVMs discovered during pregnancy should be provided with counseling to discuss the risks associated with intervention relative to those with cautious continuation of pregnancy without intervention.

For delivery, the researchers recommend cesarean section.

"Although our paradigm may differ from those at other institutions, we hope that along with the results of this study, they incite thought and invoke added caution in women with known, untreated AVMs planning to bear children," conclude the researchers in Neurosurgery.

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