Introduction: Stroke is a rare but feared complication of pregnancy and the postpartum period. Prior studies have found that older age is associated with increased risk of pregnancy-associated stroke (PAS). It is unclear to what extent pregnancy contributes to this increased risk of PAS. There is limited information on age-specific incidence ratios to assess whether the risk of PAS is comparable to stroke in similarly aged non-pregnant women.
Hypothesis: Increased incidence of PAS in older women is attributable to the increasing risk of stroke with age.
Methods: We used the 2008-2012 New York State Department of Health (NYS DOH) Statewide Planning and Research Cooperative System (SPARCS) inpatient database to identify women aged 12-50 with ischemic (ICD-9 433, 434, 436), ICH (ICD-9 431), SAH (ICD-9 430), and non-specified PAS, including post-partum stroke (ICD-9 671.7, 674). Population data were obtained from NYS DOH Vital Statistics. Age-specific incidence ratios were calculated for strokes in pregnant or postpartum women compared to non-pregnant women. We used standard age groups considered by obstetricians to be at low, moderate, or high risk for pregnancy complications, including stroke.
Results: Of 7099 stroke hospitalizations occurring in women, 386 were in pregnant women. The table shows the incidence of stroke in women stratified by pregnancy status and age group, and age-specific incidence risk ratios associated with pregnancy.
Conclusions: Compared to non-pregnant women of the same age, pregnant women appeared to be at similarly increased risk of stroke at all ages, except for those over age 40. These results suggest that pregnancy itself does not further increase the risk of stroke in older women, though they could also reflect a tendency for healthier women to have pregnancies at later ages. More research is needed to investigate the characteristics that may put younger women at increased risk of stroke, compared to their non-pregnant contemporaries.