NUMBER OF PREGNANCIES AND RISK FOR STROKE AND STROKE SUBTYPES

Objective: To examine the effect of the number of pregnancies on the s ubsequent risk for stroke and stroke subtypes. Design: Prospective coh ort study. Participants: National cohort of 3852 women aged 45 to 74 y ears who participated in the first National Health and Nutrition Exami nation Survey Epidemiology Follow-up Study. Main Outcome Measures: Str oke, cerebral infarction, and intracerebral hemorrhage during a 20-yea r follow-up period. Results: After adjusting for differences in age, w omen with 6 or more pregnancies were at an increased risk for any type of stroke (relative risk [RR] = 1.7; 95% confidence interval [CI], 1. 2-2.3) and cerebral infarction (RR = 1.6; 95% CI, 1.2-2.3). Adjustment for stroke risk factors explained some but not all of the risk associ ated with pregnancy (RR = 1.3; 95% CI, 0.9-1.9 for all stroke, and RR = 1.3; 95% CI, 0.9-1.9 for cerebral infarction). The rate of intracere bral hemorrhage was 3-fold higher among women who had been pregnant wh en compared with nulligravida women; however, this finding did not rea ch statistical significance possibly because of the small number of in tracerebral hemorrhages (n = 33). Conclusion: The number of pregnancie s may influence the risk for stroke, particularly cerebral infarction, in women.