Secular Increases in Spontaneous Subarachnoid Hemorrhage during Pregnancy: A Nationwide Sample Analysis

Understanding of the epidemiology, outcomes, and management of spontaneous subarachnoid hemorrhage (sSAH) during pregnancy is limited. Small, single center series suggest a slight increase in morbidity and mortality.

To determine if incidence of sSAH in pregnancy is increasing nationally and also to study the outcomes for this patient population.

A retrospective analysis was performed utilizing the Nationwide Inpatient Sample (NIS) and Healthcare Cost and Utilization Project for the years 2002-2014 for sSAH hospitalizations. The NIS is a large administrative database designed to produce nationally weighted estimates. Female patients age 15-49 with sSAH were identified using the International Classification of Diseases, 9th Revision, Clinical Modification code 430. Pregnancy and maternal diagnosis were identified using pregnancy related ICD codes validated by previous studies. The Cochran-Armitage trend test and parametric tests were utilized to analyze temporal trends and group comparisons. Main Outcomes and Measures: National trend for incidence of sSAH in pregnancy, age, and race/ethnicity as well as associated risk factors and outcomes.

During the time period, there were 73,692 admissions for sSAH in women age 15-49 years, of which 3978 (5.4%) occurred during pregnancy. The proportion of sSAH during pregnancy hospitalizations increased from 4.16 % to 6.33% (P-_Trend < .001) during the 12 years of the study. African-American women (8.19%) and Hispanic (7.11%) had higher rates of sSAH during pregnancy than whites (3.83%). In the NIS data, the incidence of sSAH increased from 5.4/100,000 deliveries (2002) to 8.5/100,000 deliveries (2014; P-_Trend < .0001). The greatest increase in sSAH was noted to be among pregnant African-American women from (13.4 [2002]) to (16.39 [2014]/100,000 births). Mortality was lower in pregnant women (7.69% versus 17.37%, P < .0001). Pregnant women had a higher likelihood of being discharged to home (69.78% versus 53.66%, P < .0001) and lower likelihood of discharge to long term facility (22.4% versus 28.7%, P < .0001) than nonpregnant women after sSAH hospitalization.

There is an upward trend in the incidence of sSAH occurring during pregnancy. There was disproportionate increase in incidence of sSAH in the African American and younger mothers. Outcomes were better for both pregnant and nonpregnant women treated at teaching hospitals and in pregnant women in general as compared to nonpregnant women.