Incidence of First Stroke in Pregnant and Nonpregnant Women of Childbearing Age: A Population‐Based Cohort Study From England
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- RE: Incidence of First Stroke in Pregnant and Nonpregnant Women of Childbearing Age: A Population‐Based Cohort Study From EnglandEliza C. Miller, Mitchell S.V. Elkind and Joshua Z. WilleyPublished on May 1, 2017
- Published on May 1, 2017RE: Incidence of First Stroke in Pregnant and Nonpregnant Women of Childbearing Age: A Population‐Based Cohort Study From England
- Eliza C. Miller, Vascular Neurology Fellow, Department of Neurology (Stroke), Columbia University Medical Center
- Other Contributors:
- Mitchell S.V. Elkind, Professor of Neurology and Epidemiology
- Joshua Z. Willey, Assistant Professor of Neurology
We read with great interest the cohort study by Ban et al. characterizing stroke incidence in pregnant and postpartum women in England. The authors’ finding that incidence rate ratios were increased in younger pregnant/postpartum women, compared with older women, are similar to the results of our recent population-based study in New York State (Miller et al., Risk of Pregnancy-Associated Stroke Across Age Groups in New York State, JAMA Neurol. 2016 Dec 1;73(12):1461-1467). In the study by Ban et al we were surprised, however, by the relatively low incidence of postpartum stroke in comparison to stroke around the time of delivery, where others and we have shown that postpartum stroke is more common.
One possible explanation is if the authors did not include stroke diagnoses that are pregnancy-specific diagnostic codes for cerebrovascular disease (ICD-9 674; ICD-10 099.43). The authors’ study might offer an opportunity to validate these codes in a large cohort. Similarly, the ICD-10 code category I67 was not employed; this category includes a number of rarer cerebrovascular diagnoses which have particular relevance in the postpartum period, such as intracranial venous sinus thrombosis (I67.6) and the reversible cerebral vasoconstriction syndrome (I67.841), both highly associated with postpartum stroke.Competing Interests: None declared.