SAN ANTONIO — Pregnancy-related subarachnoid hemorrhage presented most often in the postpartum period and often with severe headache, analyses of both nationwide and single-institution datasets revealed.
In an analysis of data from the Nationwide Inpatient Sample – an administrative dataset containing information on 20% of United States hospital admissions – SAH occurred at a rate of 5.6 per 100,000 deliveries and 5.0 per 100,000 pregnancy-related admissions. Two-thirds of these occurred in the postpartum period, Dr. Vanessa A. Olbrecht said.
Although rare, the incidence of SAH is increased twofold among women in the intrapartum/peripartum periods compared with the general population, and it is the second leading cause of indirect maternal death after cardiac disease. SAH needs to be considered in the differential diagnosis of postpartum headache, according to Dr. Olbrecht.
She and her associates at Massachusetts General Hospital used two data sources to investigate the epidemiology of SAH in pregnancy. From the NIS, they extracted all pregnancy-related admissions for women aged 15–44 years during 1997–2006, and identified all of those admissions with a primary or secondary diagnosis of SAH.
The second analysis was a comprehensive retrospective review of their own institution's experience with pregnancy-related SAH from 1992 through 2009. Here, they included only patients with SAH as the primary pathology, Dr. Olbrecht explained.
In the NIS, there were an estimated 2,254 cases of pregnancy-related SAH in the United States during the study period.
There was a geometric increase in SAH with age, with a doubling of the incidence from those aged 35–39 years to 40–44 years and odds ratios of 1.7 to 2.3 per every 10-year increase in age.
In a logistic regression analysis, eclampsia was the single biggest predictor of pregnancy-related SAH, with an “impressive” odds ratio of 88.4. Other significant and independent predictors included coagulopathy (odds ratio 7.2), preeclampsia superimposed on preexisting hypertension (4.2), severe preeclampsia (3.1), tobacco use (2.6), pre-existing hypertension (2.4), African-American race (2.4, compared with Caucasians), mild preeclampsia (2.1), and Hispanic race (1.6).
Compared with an age-matched cohort of non-pregnant women with SAH, the pregnant women with SAH had significantly lower in-hospital mortality, with a rate of 10.7% versus 18.7%. The proportion discharged somewhere other than home was 35.2% among the pregnant women with SAH vs. 48% among those with non-pregnancy related SAH. And the percentage who had aneurysm clipping/coiling – used as a proxy for aneurysmal SAH – was 12.1% in the pregnancy-related SAH group, compared with 44.2% among the non-pregnant SAH patients.
At Massachusetts General, there were 11 cases of SAH during the 17-year study period. Nine of the 11 had cesarean sections, and only 2 had vaginal deliveries. The women ranged in age from 19 to 42, with one-third over the age of 35 at the time of diagnosis. Half were Caucasian, 3 were African-American, and 2 were Hispanic. As in the NIS, two-thirds of the SAH occurred in the postpartum period, at a median of postpartum day 8.
The majority (9) presented with a sudden severe headache, and one-fourth (3) had seizures. Three cases were aneurysmal and were treated with craniotomy, and 2 were associated with venous sinus thrombosis. One patient died, and two were discharged home with significant neurologic deficits.
None of the study authors reported having relevant conflicts of interest.
SAH needs to be considered in the differential diagnosis of postpartum headache.
Source DR. OLBRECHT