Miscarriage is linked to an increased risk of stroke, a new study published in the British Medical Journal suggests.
Experts examined global data and found that women who had had recurrent miscarriages appeared to have a 35 per cent higher risk of non-fatal and fatal stroke.
The risk of non-fatal stroke increased with the number of miscarriages, the researchers found, with one miscarriage being linked to a 7 per cent increased risk and two with a 12 per cent increased risk.
For fatal stroke, women who suffered one miscarriage had an 8 per cent increased risk, while two was linked to a 26 per cent increased risk and three was linked to an 82 per cent increased risk.
The study, by researchers at the University of Queensland in Australia and University College London, also found that women who had suffered a stillbirth saw their risk of a non-fatal stroke increase by 31 per cent, along with a 7 per cent increased risk of fatal stroke.
Meanwhile, recurrent stillbirths were linked to a 26 per cent higher risk of fatal stroke.
Infertility was also linked to a 14 per cent higher risk of non-fatal stroke compared to women who were fertile.
Researchers suggested possible reasons for the findings, including that the link between infertility and increased stroke risk may be due to conditions such as polycystic ovary syndrome (PCOS) and premature ovarian insufficiency (POI).
A narrowing of the heart's blood vessels may also explain the increased risk of stroke among women with a history of recurrent stillbirths or miscarriages.
However, the team noted that unhealthy lifestyles also contribute to stroke risk and called for more research into the area.
Writing in the BMJ, the experts concluded: “A history of recurrent miscarriages and death or loss of a baby before or during birth could be considered a female-specific risk factor for stroke, with differences in risk according to stroke subtypes.
They added that the findings could “contribute to improved monitoring and stroke prevention for women with such a history”.
The researchers looked at eight studies carried out in Australia, China, Japan, the Netherlands, Sweden, the United Kingdom and the US.
Overall, more than 600,000 women aged 32 to 73 at the start of the study were included, of which 9,265 experienced a first non-fatal stroke (2.8 per cent), typically aged 62, and 4,003 (0.7 per cent) experienced a fatal stroke, typically aged 71.
Strokes were identified through self-reported questionnaires, hospital data or national patient registers. Fatal strokes were recorded through death registries.
Factors that may influence the results - such as body mass index and smoking status - were also taken into account. Women with non-fatal stroke before the age of 40 were excluded.