Comment Author: Diana Aguiar de Sousa, Department of Neurology, Hospital de Santa Maria, University of Lisbon, Portugal
Original Article: Lu Ban et al. 2017. “The incidence of first stroke in and around pregnancy: A population-based cohort study from Sweden” European Stroke Journal. Epub April 21, 2017. doi: 10.1177/2396987317706600
Pregnancy is associated with an increased risk of stroke. Besides being a prothrombotic state, pregnancy is also associated with relative hyperlipidaemia and hypertension. However, previous literature regarding the risk of pregnancy related stroke is limited, particularly in the distinction of the risks associated with the different time periods around pregnancy.
In this paper, Lu Ban and colleagues set out to quantify the incidence of first stroke related with pregnancy in Sweden and to compare it with background rates among women of childbearing age.
To do so, the authors have linked the Swedish Birth Registry and nationwide data on stroke obtained from the Swedish National Patient Registry. Both these registries have high quality data, as confirmed by prior analyses. The following types of stroke were considered: ischaemic stroke, intracerebral haemorrhage and subarachnoid haemorrhage.
Following this methodology, Ban and colleagues were able to identify more than 1 million pregnant women and 3000 stroke episodes occurring between 1992 and 2011. As 332 of those strokes were related with pregnancy, they have found a rate of 17 women with stroke per 100,000 deliveries.
Importantly, the authors described a higher incidence rate during the days around delivery, in accordance with data from prior studies. Another relevant finding was a decrease in the overall relative rate of stroke around delivery/early postpartum after the 90s. However, comparison with prior studies from Sweden suggests an increase in the rates of ischemic stroke, although the number of episodes of ICH was lower. Finally, a lower risk of stroke among highly educated women was also shown.
In conclusion, this nationwide population-based study of more than 1 million pregnant women confirms that the risk of stroke is significantly increased at the time of delivery and in the early postpartum period.
Further studies are needed in order to establish other factors that may contribute to this increased risk and the most appropriate strategies to prevent pregnancy related stroke.
The original article “The incidence of first stroke in and around pregnancy: A population-based cohort study from Sweden” is available in the “Online First” section of the European Stroke Journal.
- Ban L, Sultan AA, Stephansson O, Tata LJ, Sprigg N, Nelson-Piercy C, Bath PM, Ludvigsson JF. The incidence of first stroke in and around pregnancy: A population-based cohort study from Sweden. European Stroke Journal. Epub 2017 April 21.