The pooled analysis, published in the BMJ, included eight observational cohort studies from seven countries (Australia, China, Japan, the Netherlands, Sweden, the UK and the US). It was found that women with infertility, miscarriage, and stillbirth had a significantly higher risk of stroke. Scientists assessed data from over 618 thousand women aged 32 to 73 years.
Women with a history of infertility had a significantly higher risk of nonfatal stroke compared with women without infertility (hazard ratio 1.14). Further analysis by stroke subtype showed an increased association between miscarriage and ischemic stroke (hazard ratio 1.15).
In the miscarriage group, the risk of stroke increased with the number of miscarriages, with adjusted hazard ratios of 1.07, 1.12, and 1.35 for women with one, two, and three or more miscarriages, respectively.
Infertility is associated with an increased risk of nonfatal ischemic stroke, and stillbirth is associated with fatal hemorrhagic stroke. While late miscarriage increased the risk of two types of stroke at once.
The risk of fatal stroke was higher in women with a stillbirth, and it increased with the number of stillbirths (hazard ratio 0.97 and 1.26 for women with one stillbirth and two or more, respectively).
Endothelial dysfunction can lead to pregnancy loss due to placenta-related defects, persist after complicated pregnancies, and contribute to the development of stroke due to decreased vasodilation, proinflammatory status, and prothrombotic properties, the authors report.
The authors also believe that pregnancy outcomes have a major impact on future health. Clinicians need to take into account patients’ obstetric history to reduce the risk of stroke. Early monitoring of women with a history of recurrent miscarriages and stillbirths for stroke risk factors such as high blood pressure, blood sugar, and lipid levels is recommended.