unruptured aneurysm Researchers from the University of Florida believe women with unruptured aneurysm are not at increased risk of rupture during pregnancy, according to a study published in Neurology. The study also noted that C-section deliveries, statistically higher in women with aneurysm, may be unfounded. According to Dr. Brian Hohn, lead author of the study, information on rupture risk is relatively minimal. This study aimed to fill in gaps in literature.

Data for the study was collected via a Nationwide Inpatient Sample. There were more than 2.7 million pregnancies included in data collected between 1988 and 2009. Of these pregnancies, 193 were in women with aneurysm (unruptured) and 714 with aneurysm (ruptured). Researchers assumed an overall unruptured aneurysm rate of about 4% in the general population and about 2% of those women falling into the child-bearing age category. Using this assumption, researchers estimated up to 48,000 of the women in the study could be living with an unruptured aneurysm. That number lead to an overall risk of 1.4% for having an unruptured aneurysm during pregnancy without clinical knowledge.

Of the 17 million hospitalizations during delivery, 390 involved aneurysm (218 unruptured and 172 ruptured). Researchers again used the assumed 1.8% to estimate up to 312,000 of the hospitalizations involved unruptured aneurysm. Taking into account the number of women hospitalized for ruptured aneurysm, researchers estimated a risk of rupture during pregnancy of 0.05%.

Experts are unsure about the accuracy of the study's estimates. According to a neurosurgery professor at the University of Toronto, R. Loch Macdonald, the information used for the study was not population-based, which could lead to altered findings. Further potential problems were noted with medical coding. MacDonald estimates that only 20% of the medical coding was completed correctly, leaving a huge gap in potential cases and increasing the overall risk. Loch later admitted in his comment on the study that the study result is beneficial as literature and may accurately report low overall risk. “Although intracranial hemorrhage is an important cause of obstetrical morbidity and mortality, aneurysmal cases are rare, and, if they are more likely to occur during pregnancy and the puerperium, then this increased risk is likely to be small.”

Source: Young Woo Kim MD, Dan Neal MS, Brian Hohn MD. Cerebral Aneurysms in Pregnancy and Delivery: Pregnancy and Delivery Do Not Increase the Risk of Aneurysm Rupture. February 2013. Volume 72-Issue 2-p 143–150.DOI: 10.1227/NEU.0b013e3182796af9.